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  • 1.
    Abdelmoumene, Youcef
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Luftfiltermätningar av atmosfärisk radioaktivitet: Mätningar av luftfilter med gammaspektroskopi2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Projektet handlar om att mäta atmosfärisk radioaktivitet och utforma en procedur för hur en luftfiltermaskin och en detektor kan användas för att samla in och mäta atmosfärisk radioaktivitet. Det innehåller luftinsamling, förberedelse av prov, mätning och analys. Varierande mättider och inställningar undersöktes hur det påverkar resultaten som redogör metoden för en kvalitativ mätning. För att kunna tolka resultaten är det viktigt att förstå detektorns samt luftfiltermaskinens egenskaper. Projektet har krävt luftinsamling och långa mätningar i syfte att ta reda på vilka luftburna isotoper som kan insamlas från atmosfären, och för att förstå detektorn och luftfiltrets känslighet har olika långa luftinsamlingsperioder och mätningar använts.

     Resultatet visar hur mätosäkerheten påverkas av subtraktionen av bakgrunden. Dessutom beskriver resultaten från analysen att det finns en begränsad tid som filtren kan samla in partiklar från luften. Resultaten visar också att längre mätningar med detektorn resulterar i tydligare toppar i ett spektrum och kortare mätningar resulterar i högre mätosäkerhet. De radioaktiva isotoper som identifierades var beryllium-7, radondöttrar från bakgrunden och cesium-137. Dessa isotoper var förväntade och inga isotoper hittades som tyder på att ett utsläpp från Forsmarks kärnkraftverk har skett.  

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  • 2. Ablikim, M.
    et al.
    Adlarson, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Biernat, Jacek
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Ikegami Andersson, Walter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Johansson, Tord
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Kupsc, Andrzej
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Li, Cui
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Papenbrock, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Pettersson, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Schönning, Karin
    Thorén, Viktor
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Wolke, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Zou, J. H.
    Search for the decay eta ' -> gamma gamma eta (Search for the decay η′→γγη)2019In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 100, no 5, article id 052015Article in journal (Refereed)
    Abstract [en]

    Using a data sample of 1.31 x 10(9) J/psi events collected with the BESIII detector, a search for eta' -> gamma gamma eta via J/psi ->gamma eta' is performed for the first time. No significant eta' signal is observed in the gamma gamma eta invariant mass spectrum, and the branching fraction of eta' -> gamma gamma eta is determined to be less than 1.33 x 10(-4) at the 90% confidence level.

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  • 3.
    Acciarri, R.
    et al.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Adams, C.
    Yale Univ, New Haven, CT 06520 USA.
    Asaadi, J.
    Univ Texas Arlington, Arlington, TX 76019 USA.
    Baller, B.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Bolton, T.
    Kansas State Univ, Manhattan, KS 66506 USA.
    Bromberg, C.
    Michigan State Univ, E Lansing, MI 48824 USA.
    Cavanna, F.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Church, E.
    Pacific Northwest Natl Lab, Richland, WA 99354 USA.
    Edmunds, D.
    Michigan State Univ, E Lansing, MI 48824 USA.
    Ereditato, A.
    Univ Bern, CH-3012 Bern, Switzerland.
    Farooq, S.
    Kansas State Univ, Manhattan, KS 66506 USA.
    Ferrari, A.
    CERN, CH-1211 Geneva 23, Switzerland.
    Fitzpatrick, R. S.
    Univ Michigan, Ann Arbor, MI 48109 USA.
    Fleming, B.
    Yale Univ, New Haven, CT 06520 USA.
    Hackenburg, A.
    Yale Univ, New Haven, CT 06520 USA.
    Horton-Smith, G.
    Kansas State Univ, Manhattan, KS 66506 USA.
    James, C.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Lang, K.
    Univ Texas Austin, Austin, TX 78712 USA.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lepetic, I.
    IIT, Chicago, IL 60616 USA.
    Littlejohn, B. R.
    IIT, Chicago, IL 60616 USA.
    Luo, X.
    Yale Univ, New Haven, CT 06520 USA.
    Mehdiyev, R.
    Univ Texas Austin, Austin, TX 78712 USA.
    Page, B.
    Michigan State Univ, E Lansing, MI 48824 USA.
    Palamara, O.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Rebel, B.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Sala, P. R.
    INFN Milano, INFN Sez Milano, I-20133 Milan, Italy.
    Scanavini, G.
    Yale Univ, New Haven, CT 06520 USA.
    Schukraft, A.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Smirnov, G.
    CERN, CH-1211 Geneva 23, Switzerland.
    Soderberg, M.
    Syracuse Univ, Syracuse, NY 13244 USA.
    Spitz, J.
    Univ Michigan, Ann Arbor, MI 48109 USA.
    Szelc, A. M.
    Univ Manchester, Manchester M13 9PL, Lancs, England.
    Weber, M.
    Univ Bern, CH-3012 Bern, Switzerland.
    Wu, W.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Yang, T.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Zeller, G. P.
    Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA.
    Demonstration of MeV-scale physics in liquid argon time projection chambers using ArgoNeuT2019In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 99, no 1, article id 012002Article in journal (Refereed)
    Abstract [en]

    MeV-scale energy depositions by low-energy photons produced in neutrino-argon interactions have been identified and reconstructed in ArgoNeuT liquid argon time projection chamber (LArTPC) data. ArgoNeuT data collected on the NuMI beam at Fermilab were analyzed to select isolated low-energy depositions in the TPC volume. The total number, reconstructed energies, and positions of these depositions have been compared to those from simulations of neutrino-argon interactions using the FLUKA Monte Carlo generator. Measured features are consistent with energy depositions from photons produced by deexcitation of the neutrino's target nucleus and by inelastic scattering of primary neutrons produced by neutrino-argon interactions. This study represents a successful reconstruction of physics at the MeV scale in a LArTPC, a capability of crucial importance for detection and reconstruction of supernova and solar neutrino interactions in future large LArTPCs.

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  • 4.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Karimi Aghda, Soheil
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Miljanovic, Danilo J.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Low temperature oxidation behavior of Mo2BC coatings2020In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, no 2, article id 023403Article in journal (Refereed)
    Abstract [en]

    Mo2BC exhibits a unique combination of high stiffness and moderate ductility, enabling the application as a protective and wear resistant coating. As the low temperature oxidation behavior of Mo2BC coatings is unexplored, direct current magnetron sputtered Mo2BC coatings were oxidized at temperatures ranging from 500 to 100 degrees C for up to 28 days. Time-of-flight elastic recoil detection analysis reveals that the onset of oxidation takes place at approximately 300 degrees C as a significant increase in the O content was observed. Crystalline oxide scales containing orthorhombic MoO3 were identified after oxidation for 15 min at 500 degrees C and 10 days at 200 degrees C. Isothermal oxidation at 200 and 100 degrees C exhibits oxide scale thicknesses of 401 +/- 33 and 22 +/- 10 nm after 14 days. Oxidation for 28 days at 100 degrees C exhibits an oxide scale thickness of 13 +/- 3 nm, which is comparable to the aforementioned oxide scale thickness after oxidation for 14 days at 100 degrees C. Based on the combination of mechanical properties and the here reported low temperature oxidation behavior, Mo2BC coatings qualify for applications in solid wood machining and low temperature forming processes at temperatures close to 100 degrees C or below.

  • 5.
    Achenbach, Jan-Ole
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Aachen, Germany.
    Mraz, Stanislav
    Rhein Westfal TH Aachen, Mat Chem, Aachen, Germany.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Aachen, Germany.
    Correlative Experimental and Theoretical Investigation of the Angle-Resolved Composition Evolution of Thin Films Sputtered from a Compound Mo2BC Targe2019In: Coatings, ISSN 2079-6412, Vol. 9, no 3, article id 206Article in journal (Refereed)
    Abstract [en]

    The angle-resolved composition evolution of Mo-B-C thin films deposited from a Mo2BC compound target was investigated experimentally and theoretically. Depositions were carried out by direct current magnetron sputtering (DCMS) in a pressure range from 0.09 to 0.98 Pa in Ar and Kr. The substrates were placed at specific angles α with respect to the target normal from 0 to ±67.5°. A model based on TRIDYN and SIMTRA was used to calculate the influence of the sputtering gas on the angular distribution function of the sputtered species at the target, their transport through the gas phase, and film composition. Experimental pressure- and sputtering gas-dependent thin film chemical composition data are in good agreement with simulated angle-resolved film composition data. In Ar, the pressure-induced film composition variations at a particular α are within the error of the EDX measurements. On the contrary, an order of magnitude increase in Kr pressure results in an increase of the Mo concentration measured at α = 0° from 36 at.% to 43 at.%. It is shown that the mass ratio between sputtering gas and sputtered species defines the scattering angle within the collision cascades in the target, as well as for the collisions in the gas phase, which in turn defines the angle- and pressure-dependent film compositions.

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  • 6.
    Adalsteinsson, Sigurbjörn Már
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Moro, Marcos V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moldarev, Dmitrii
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Moscow Engn Phys Inst, Dept Mat Sci, Moscow 115409S, Russia..
    Droulias, Sotiris
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Wolff, Max
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Moscow Engn Phys Inst, Dept Mat Sci, Moscow 115409S, Russia..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Sweden.;Uppsala Univ, Tandem Lab, Box 529, S-75120 Uppsala, Sweden..
    Correlating chemical composition and optical properties of photochromic rare-earth oxyhydrides using ion beam analysis2020In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 485, p. 36-40Article in journal (Refereed)
    Abstract [en]

    We relate the photochromic response of rare-earth oxyhydride thin films (YHO, NdHO, GdHO and DyHO) synthesized by reactive magnetron sputtering to chemical composition. Depth profiles of the sample composition are extracted by a multi-method ion beam analysis approach. The total areal density of the thin films is deduced from Rutherford Backscattering Spectrometry while coincidence Time-of-Flight/Energy Elastic Recoil Detection Analysis provides depth-profiles of the film constituents. High-resolution depth profiles of the concentration of light species, i.e. hydrogen and oxygen, are additionally extracted from Nuclear Reaction Analysis and Elastic Backscattering Spectrometry, respectively. The photochromic response of the films is measured by optical transmission spectroscopy before and after illumination. We report photochromic properties for YHO, NdHO, GdHO and DyHO for chemical compositions described by the formula REH2-delta O delta in the range of 0.45 < 6 < 1.5.

  • 7.
    Adlarson, Patrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Augustyniak, W.
    Natl Ctr Nucl Res, Dept Nucl Phys, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Bardan, W.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Bashkanov, M.
    Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England..
    Bergmann, F. S.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Berlowski, M.
    Natl Ctr Nucl Res, High Energy Phys Dept, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Bhatt, H.
    Indian Inst Technol, Dept Phys, Mumbai 400076, Maharashtra, India..
    Buescher, M.
    Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich, Germany.;Heinrich Heine Univ Dusseldorf, Inst Laser & Plasmaphys, D-40225 Dusseldorf, Germany..
    Calén, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Ciepal, I
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Clement, H.
    Eberhard Karls Univ Tubingen, Phys Inst, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Tubingen, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany..
    Coderre, D.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;Ruhr Univ Bochum, Inst Expt Phys 1, Univ Str 150, D-44780 Bochum, Germany.;Univ Bern, Albert Einstein Ctr Fundamental Phys, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Czerwinski, E.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Demmich, K.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Doroshkevich, E.
    Eberhard Karls Univ Tubingen, Phys Inst, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Tubingen, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany..
    Engels, R.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Erven, A.
    Forschungszentrum Julich, Zent Inst Engn Elekt & Analyt, D-52425 Julich, Germany..
    Erven, W.
    Forschungszentrum Julich, Zent Inst Engn Elekt & Analyt, D-52425 Julich, Germany..
    Eyrich, W.
    Friedrich Alexander Univ Erlangen Nurnberg, Phys Inst, Erwin Rommel Str 1, D-91058 Erlangen, Germany..
    Fedorets, P.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;State Sci Ctr Russian Federat, Inst Theoret & Expt Phys, Bolshaya Cheremushkinskaya 25, Moscow 117218, Russia..
    Foehl, K.
    Justus Liebig Univ Giessen, Phys Inst 2, Heinrich Buff Ring 16, D-35392 Giessen, Germany..
    Fransson, K.
    Uppsala Univ, Dept Phys & Astron, Div Nucl Phys, Box 516, S-75120 Uppsala, Sweden..
    Goldenbaum, F.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Goslawski, P.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Goswami, A.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;Indian Inst Technol Indore, Dept Phys, Khandwa Rd, Indore 452017, Madhya Pradesh, India..
    Grigoryev, K.
    Rhein Westfal TH Aachen, Phys Inst B 3, Phys Zentrum, D-52056 Aachen, Germany.;Petersburg Nucl Phys Inst, High Energy Phys Div, Orlova Rosha 2, Gatchina 188300, Leningrad Distr, Russia..
    Gullström, C-O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Hauenstein, F.
    Friedrich Alexander Univ Erlangen Nurnberg, Phys Inst, Erwin Rommel Str 1, D-91058 Erlangen, Germany..
    Heijkenskjöld, L.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hejny, V
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Hodana, M.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Höistad, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Huesken, N.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Jany, A.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Jany, B. R.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Johansson, T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kamys, B.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Kemmerling, G.
    Forschungszentrum Julich, Zent Inst Engn Elekt & Analyt, D-52425 Julich, Germany..
    Khan, F. A.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Khoukaz, A.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Kirillov, D. A.
    Joint Inst Nucl Phys, Veksler & Baldin Lab High Energiy Phys, Joliot Curie 6, Dubna 141980, Russia..
    Kistryn, S.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Kleines, H.
    Forschungszentrum Julich, Zent Inst Engn Elekt & Analyt, D-52425 Julich, Germany..
    Klos, B.
    Univ Silesia, August Chelkowski Inst Phys, Uniwersytecka 4, PL-40007 Katowice, Poland..
    Krapp, M.
    Friedrich Alexander Univ Erlangen Nurnberg, Phys Inst, Erwin Rommel Str 1, D-91058 Erlangen, Germany..
    Krzemien, W.
    Natl Ctr Nucl Res, High Energy Phys Div, PL-05400 Otwock, Poland..
    Kulessa, P.
    Polish Acad Sci, Henryk Niewodniczanski Inst Nucl Phys, 152 Radzikowskiego St, PL-31342 Krakow, Poland..
    Kupsc, Andrzej
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Lalwani, K.
    Indian Inst Technol, Dept Phys, Mumbai 400076, Maharashtra, India.;Univ Delhi, Dept Phys & Astrophys, Delhi 110007, India..
    Lersch, D.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Lorentz, B.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Magiera, A.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Maier, R.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Marciniewski, Pawel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Marianski, B.
    Natl Ctr Nucl Res, Dept Nucl Phys, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Mikirtychiants, M.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;Ruhr Univ Bochum, Inst Expt Phys 1, Univ Str 150, D-44780 Bochum, Germany.;Petersburg Nucl Phys Inst, High Energy Phys Div, Orlova Rosha 2, Gatchina 188300, Leningrad Distr, Russia..
    Morsch, H-P
    Natl Ctr Nucl Res, Dept Nucl Phys, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Moskal, P.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Ohm, H.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Ozerianska, I
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    del Rio, E. Perez
    Eberhard Karls Univ Tubingen, Phys Inst, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Tubingen, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Sapienza, Dipartimento Fis, Rome, Italy.;Ist Nazl Fis Nucl, Sez Roma, Rome, Italy..
    Piskunov, N. M.
    Joint Inst Nucl Phys, Veksler & Baldin Lab High Energiy Phys, Joliot Curie 6, Dubna 141980, Russia..
    Podkopal, P.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Prasuhn, D.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Pricking, A.
    Eberhard Karls Univ Tubingen, Phys Inst, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Tubingen, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany..
    Pszczel, D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Natl Ctr Nucl Res, High Energy Phys Dept, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Pysz, K.
    Polish Acad Sci, Henryk Niewodniczanski Inst Nucl Phys, 152 Radzikowskiego St, PL-31342 Krakow, Poland..
    Pyszniak, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala Univ, Dept Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Redmer, C. F.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala Univ, Dept Phys & Astron, Div Nucl Phys, Box 516,Johannes Gutenberg Univ Mainz, Inst Kernphys, Johann Joachim Becher Weg 45, D-55128 Mainz, Germany..
    Ritman, J.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;Ruhr Univ Bochum, Inst Expt Phys 1, Univ Str 150, D-44780 Bochum, Germany..
    Roy, A.
    Indian Inst Technol Indore, Dept Phys, Khandwa Rd, Indore 452017, Madhya Pradesh, India..
    Rudy, Z.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Sawant, S.
    Indian Inst Technol, Dept Phys, Mumbai 400076, Maharashtra, India.;Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Schadmand, S.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Sefzick, T.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Serdyuk, V
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany.;Joint Inst Nucl Phys, Dzhelepov Lab Nucl Problems, Joliot Curie 6, Dubna 141980, Russia..
    Siudak, R.
    Polish Acad Sci, Henryk Niewodniczanski Inst Nucl Phys, 152 Radzikowskiego St, PL-31342 Krakow, Poland..
    Skorodko, T.
    Eberhard Karls Univ Tubingen, Phys Inst, Morgenstelle 14, D-72076 Tubingen, Germany.;Univ Tubingen, Kepler Ctr Astro & Particle Phys, Morgenstelle 14, D-72076 Tubingen, Germany.;Tomsk State Univ, Dept Phys, 36 Lenin Ave, Tomsk 634050, Russia..
    Skurzok, M.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Smyrski, J.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Sopov, V
    State Sci Ctr Russian Federat, Inst Theoret & Expt Phys, Bolshaya Cheremushkinskaya 25, Moscow 117218, Russia..
    Stassen, R.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Stepaniak, J.
    Natl Ctr Nucl Res, High Energy Phys Dept, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Stephan, E.
    Univ Silesia, August Chelkowski Inst Phys, Uniwersytecka 4, PL-40007 Katowice, Poland..
    Sterzenbach, G.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Stockhorst, H.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Stroeher, H.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Szczurek, A.
    Polish Acad Sci, Henryk Niewodniczanski Inst Nucl Phys, 152 Radzikowskiego St, PL-31342 Krakow, Poland..
    Taeschner, A.
    Westfalische Wilhelms Univ Munster, Inst Kernphys, Wilhelm Klemm Str 9, D-48149 Munster, Germany..
    Trzcinski, A.
    Natl Ctr Nucl Res, Dept Nucl Phys, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Varma, R.
    Indian Inst Technol, Dept Phys, Mumbai 400076, Maharashtra, India..
    Wolke, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Wronska, A.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Wuestner, P.
    Forschungszentrum Julich, Zent Inst Engn Elekt & Analyt, D-52425 Julich, Germany..
    Wurm, P.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Yamamoto, A.
    High Energy Accelerator Res Org KEK, Tsukuba, Ibaraki 3050801, Japan..
    Yurev, L.
    Joint Inst Nucl Phys, Dzhelepov Lab Nucl Problems, Joliot Curie 6, Dubna 141980, Russia.;Univ Sheffield, Dept Phys & Astron, Hounsfield Rd, Sheffield S3 7RH, S Yorkshire, England..
    Zabierowski, J.
    Natl Ctr Nucl Res, Astrophys Div, Box 447, PL-90950 Lodz, Poland..
    Zielinski, M. J.
    Jagiellonian Univ, Inst Phys, Ul Reymonta 4, PL-30059 Krakow, Poland..
    Zink, A.
    Friedrich Alexander Univ Erlangen Nurnberg, Phys Inst, Erwin Rommel Str 1, D-91058 Erlangen, Germany..
    Zlomanczuk, Jozef
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
    Zupranski, P.
    Natl Ctr Nucl Res, Dept Nucl Phys, Ul Hoza 69, PL-00681 Warsaw, Poland..
    Zurek, M.
    Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany..
    Workman, R. L.
    George Washington Univ, Dept Phys, Data Anal Ctr, Inst Nucl Studies, Washington, DC 20052 USA..
    Briscoe, W. J.
    George Washington Univ, Dept Phys, Data Anal Ctr, Inst Nucl Studies, Washington, DC 20052 USA..
    Strakovsky, I. I.
    George Washington Univ, Dept Phys, Data Anal Ctr, Inst Nucl Studies, Washington, DC 20052 USA..
    Svarc, A.
    Rudjer Boskovic Inst, Bijenicka Cesta 54,POB 180, Zagreb 10002, Croatia.;Tesla Biotech, Mandlova 7, Zagreb 10002, Croatia..
    Differential cross sections for neutron-proton scattering in the region of the d* (2380) dibaryon resonance2020In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 102, no 1, article id 015204Article in journal (Refereed)
    Abstract [en]

    Differential cross sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized (n) over barp scattering performed in the energy region of the d* (2380) dibaryon resonance covering the range of beam energies T-n = 0.98-1.29 GeV (root s = 2.32-2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp -> np + p(spectator). In this way the np differential cross section sigma (Theta) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power A(y)(Theta) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D-3(3) - (3)G(3) waves.

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  • 8. Adoo, N.A.
    et al.
    Nyarko, B.J.B.
    Akaho, E.H.K.
    Alhassan, Erwin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Agbodemegbe, V.Y.
    Bansah, C.Y.
    Della, R.
    Determination of thermal hydraulic data of GHARR-1 under reactivity insertion transients using the PARET/ANL code2011In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 241, p. 5303-5210Article in journal (Refereed)
    Abstract [en]

    The PARET/ANL code has been adapted by the IAEA for testing transient behaviour in research reactors since it provides a coupled thermal hydrodynamic and point kinetics capability for estimating thermalhydraulic margins. A two-channel power peaking profile of the Ghana Research Reactor-1 (GHARR-1) has been developed for the PARET/ANL (Version 7.3; 2007) using the Monte Carlo N-Particle code (MCNP) to determine the thermal hydraulic data for reactivity insertion transients in the range of 2.0×10^−3k/k to 5.5×10^−3k/k. Peak clad and coolant temperatures ranged from 59.18 ◦C to 112.36 ◦C and 42.95 ◦C to 79.42 ◦C respectively. Calculated safety margins (DNBR) satisfied the MNSR thermal hydraulic design criteria for which no boiling occurs in the reactor core. The generated thermal hydraulic data demonstrated a high inherent safety feature of GHARR-1 for which the high negative reactivity feedback of the moderator limits power excursion and consequently the escalation of the clad temperature.

  • 9.
    Aghda, Soheil Karimi
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Bogdanovski, Dimitri
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Löfler, Lukas
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.
    Sua, Heng Han
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Patterer, Lena
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    le Febvrier, Arnaud
    Linköping Univ, Dept Phys Chem & Biol IFM, Thin Film Phys Div, SE-58183 Linköping, Sweden..
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Valence electron concentration- and N vacancy-induced elasticity in cubic early transition metal nitrides2023In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 255, article id 119078Article in journal (Refereed)
    Abstract [en]

    Motivated by frequently reported deviations from stoichiometry in cubic transition metal nitride (TMNx) thin films, the effect of N-vacancy concentration on the elastic properties of cubic TiNx, ZrNx, VNx, NbNx, and MoNx (0.72 & LE; x & LE; 1.00) is systematically studied by density functional theory (DFT) calculations. The predictions are validated experimentally for VNx (0.77 & LE; x & LE; 0.97). The DFT results indicate that the elastic behavior of the TMNx depends on both the N-vacancy concentration and the valence electron concentration (VEC) of the transition metal: While TiNx and ZrNx exhibit vacancy-induced reductions in elastic modulus, VNx and NbNx show an increase. These trends can be rationalized by considering vacancy-induced changes in elastic anisotropy and bonding. While introduction of N-vacancies in TiNx results in a significant reduction of elastic modulus along all directions and a lower average bond strength of Ti-N, the vacancy-induced reduction in [001] direction of VNx is overcompensated by the higher stiffness along [011] and [111] directions, resulting in a higher average bond strength of V-N. To validate the predicted vacancy-induced changes in elasticity experimentally, close-to-singlecrystal VNx (0.77 & LE; x & LE; 0.97) are grown on MgO(001) substrates. As the N-content is reduced, the relaxed lattice parameter a0, as probed by X-ray diffraction, decreases from 4.128 & ANGS; to 4.096 & ANGS;. This reduction in lattice parameter is accompanied by an anomalous 11% increase in elastic modulus, as determined by nanoindentation. As the experimental data agree with the predictions, the elasticity enhancement in VNx upon N-vacancy formation can be understood based on the concomitant changes in elastic anisotropy and bonding.

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  • 10.
    Aghda, Soheil Karimi
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Music, Denis
    Malmö Univ, Dept Mat Sci & Appl Math, S-20506 Malmö, Sweden..
    Unutulmazsoy, Yeliz
    Leibniz Inst Surface Engn IOM, Permoserstr 15, D-04318 Leipzig, Germany..
    Mraz, Stanislav
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Bogdanovski, Dimitri
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Fidanboy, Gonenc
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Mendez, Alba San Jose
    Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Anders, Andre
    Leibniz Inst Surface Engn IOM, Permoserstr 15, D-04318 Leipzig, Germany.;Univ Leipzig, Felix Bloch Inst, Linnestr 5, D-04103 Leipzig, Germany..
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Ion kinetic energy- and ion flux-dependent mechanical properties and thermal stability of (Ti,Al)N thin films2023In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 250, article id 118864Article in journal (Refereed)
    Abstract [en]

    Ion-irradiation-induced changes in structure, elastic properties, and thermal stability of metastable c-(Ti,Al)N thin films synthesized by high-power pulsed magnetron sputtering (HPPMS) and cathodic arc deposition (CAD) are systematically investigated by experiments and density functional theory (DFT) simulations. While films deposited by HPPMS show a random orientation at ion kinetic energies (Ek)>105 eV, an evolution towards (111) orientation is observed in CAD films for Ek>144 eV. The measured ion energy flux at the growing film surface is 3.3 times larger for CAD compared to HPPMS. Hence, it is inferred that formation of the strong (111) texture in CAD films is caused by the ion flux-and ion energy-induced strain energy minimization in defective c-(Ti,Al)N. The ion energy-dependent elastic modulus can be rationalized by considering the ion energy-and orientation -dependent formation of point defects from DFT predictions: The balancing effects of bombardment-induced Frenkel defects formation and the concurrent evolution of compressive intrinsic stress result in the apparent independence of the elastic modulus from Ek for HPPMS films without preferential orientation. However, an ion energy-dependent elastic modulus reduction of similar to 18% for the CAD films can be understood by considering the 34% higher Frenkel pair concentration formed at Ek=182 eV upon irradiation of the experimentally observed (111)-oriented (Ti,Al)N in comparison to the (200)-configuration at similar Ek. Moreover, the effect of Frenkel pair concentration on the thermal stability of metastable c-(Ti,Al)N is investigated by differential scanning calorimetry: Ion-irradiation-induced increase in Frenkel pairs concentration retards the wurtzite formation temperature by up to 206 degrees C.

  • 11.
    Ahnesjö, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tomographic reconstruction of subchannel void measurements of nuclear fuel geometries2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Westinghouse FRIGG loop in Västerås, Sweden, has been used to study the distribution of steam in the coolant flow of nuclear fuel elements, which is known as the void distribution. For this purpose, electrically heated mock-ups of a quarter BWR fuel bundles in the SVEA-96 geometry were studied by means of gamma tomography in the late 1990s. Several test campaigns were conducted, with good results, but not all the collected data was evaluated at the time. In this work, tomographic raw data of SVEA-96 geometry is evaluated using two different tomographic reconstruction methods, an algebraic (iterative) method and filtered back-projection. Reference objects of known composition (liquid water) are used to quantify the decrease in attenuation arising from the presence of the void, which is used to create a map of the void in the horizontal cross sections of the fuel at various axial locations. The resulting detailed void distributions are averaged over subchannels and the subchannel steam core for comparison with simulations. The focus of this work is on the void distribution at high axial locations in the fuel, in fuel bundles with part-length fuel-rods. Measurements in the region above the part-length rods are compared with simulations and the reliability of each method is discussed. The algebraic method is found to be more reliable than the filtered back-projection method for this setup. A reasonable agreement between measurements and predictions is shown. The void, in both cases, appears to be slightly lower in the corner downstream the part-length rods.

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  • 12.
    Ahnesjö, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Le Corre, Jean-Marie
    Westinghouse Electric Sweden AB.
    Andersson, Stig
    Westinghouse Electric Sweden AB.
    Tomographic reconstructions and predictions of radial void distribution in BWR fuel bundle with part-length rods2015Conference paper (Refereed)
    Abstract [en]

    The Westinghouse FRIGG facility, in Västerås/Sweden, is dedicated to the measurement of critical power,stability and pressure drop in fuel rod bundles under BWR operating conditions (steady-state andtransient). Capability to measure cross-sectional void and radial void distributions during steady-stateoperation was already considered when the facility was built in the late 1960s, using gamma transmissionmeasurements. In the 1990s, redesigned equipment was installed to allow for full 2D tomography andsome test campaigns were successfully run where the void was measured in the Westinghouse SVEA-96fuel bundle geometry with and without part-length rods.

    In this paper, the tomographic raw data from the SVEA-96 void measurement campaigns are revisitedusing various tomographic reconstruction techniques. This includes an algebraic method and a filteredback-projection method. Challenges, for example due to artifacts created by high difference in gammaabsorption, or to accurately identify the location of the bundle structure, are resolved. The resultingdetailed void distributions are then averaged over entire sub-channels or within the steam core only, forcomparison against sub-channel simulations.

    The resulting void distributions are compared against sub-channel void predictions using the VIPREW/MEFISTO code. The region downstream the part-length rods are of particular interest to investigatehow the void in the steam core is redistributed within the open region of the bundle. The comparisonshows a reasonable agreement between the measurements and the predictions.

  • 13. Aho-Mantila, L.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Asp, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET2017In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 3, article id 035003Article in journal (Refereed)
    Abstract [en]

    The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.

  • 14.
    Aiba, N.
    et al.
    Natl Inst Quantum & Radiol Sci & Technol, Rokkasho, Aomori, Japan.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res, Otwock, Poland.
    Analysis of ELM stability with extended MHD models in JET, JT-60U and future JT-60SA tokamak plasmas2018In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 60, no 1, article id 014032Article in journal (Refereed)
    Abstract [en]

    The stability with respect to a peeling-ballooning mode (PBM) was investigated numerically with extended MHD simulation codes in JET, JT-60U and future JT-60SA plasmas. The MINERVA-DI code was used to analyze the linear stability, including the effects of rotation and ion diamagnetic drift (omega(*i)), in JET-ILW and JT-60SA plasmas, and the JOREK code was used to simulate nonlinear dynamics with rotation, viscosity and resistivity in JT-60U plasmas. It was validated quantitatively that the ELM trigger condition in JET-ILW plasmas can be reasonably explained by taking into account both the rotation and omega(*i) effects in the numerical analysis. When deuterium poloidal rotation is evaluated based on neoclassical theory, an increase in the effective charge of plasma destabilizes the PBM because of an acceleration of rotation and a decrease in omega(*i). The difference in the amount of ELM energy loss in JT-60U plasmas rotating in opposite directions was reproduced qualitatively with JOREK. By comparing the ELM affected areas with linear eigenfunctions, it was confirmed that the difference in the linear stability property, due not to the rotation direction but to the plasma density profile, is thought to be responsible for changing the ELM energy loss just after the ELM crash. A predictive study to determine the pedestal profiles in JT-60SA was performed by updating the EPED1 model to include the rotation and w*i effects in the PBM stability analysis. It was shown that the plasma rotation predicted with the neoclassical toroidal viscosity degrades the pedestal performance by about 10% by destabilizing the PBM, but the pressure pedestal height will be high enough to achieve the target parameters required for the ITER-like shape inductive scenario in JT-60SA.

  • 15. Aiba, N.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Numerical analysis of ELM stability with rotation and ion diamagnetic drift effects in JET2017In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 57, no 12, article id 126001Article in journal (Refereed)
    Abstract [en]

    Stability to the type-I edge localized mode (ELM) in JET plasmas was investigated numerically by analyzing the stability to a peeling-ballooning mode with the effects of plasma rotation and ion diamagnetic drift. The numerical analysis was performed by solving the extended Frieman-Rotenberg equation with the MINERVA-DI code. To take into account these effects in the stability analysis self-consistently, the procedure of JET equilibrium reconstruction was updated to include the profiles of ion temperature and toroidal rotation, which are determined based on the measurement data in experiments. With the new procedure and MINERVA-DI, it was identified that the stability analysis including the rotation effect can explain the ELM trigger condition in JET with ITER like wall (JET-ILW), though the stability in JET with carbon wall (JET-C) is hardly affected by rotation. The key difference is that the rotation shear in JET-ILW plasmas analyzed in this study is larger than that in JET-C ones, the shear which enhances the dynamic pressure destabilizing a peeling-ballooning mode. In addition, the increase of the toroidal mode number of the unstable MHD mode determining the ELM trigger condition is also important when the plasma density is high in JET-ILW. Though such modes with high toroidal mode number are strongly stabilized by the ion diamagnetic drift effect, it was found that plasma rotation can sometimes overcome this stabilizing effect and destabilizes the peeling-ballooning modes in JET-ILW.

  • 16.
    Akansel, Serkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Kumar, Ankit
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Venugopal, Vijayaharan A.
    Seagate Technol, Londonderry BT48 0BF, North Ireland.
    Esteban-Puyuelo, Raquel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Banerjee, Rudra
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Autieri, Carmine
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Brucas, Rimantas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Behera, Nilamani
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Sortica, Mauricio A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Basu, Swaraj
    Seagate Technol, Londonderry BT48 0BF, North Ireland.
    Gubbins, Mark A.
    Seagate Technol, Londonderry BT48 0BF, North Ireland.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Enhanced Gilbert damping in Re-doped FeCo films: Combined experimental and theoretical study2019In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 17, article id 174408Article in journal (Refereed)
    Abstract [en]

    The effects of rhenium doping in the range 0-10 at.% on the static and dynamic magnetic properties of Fe65Co35 thin films have been studied experimentally as well as with first-principles electronic structure calculations focusing on the change of the saturation magnetization (M-s) and the Gilbert damping parameter (alpha). Both experimental and theoretical results show that M-s decreases with increasing Re-doping level, while at the same time alpha increases. The experimental low temperature saturation magnetic induction exhibits a 29% decrease, from 2.31 to 1.64 T, in the investigated doping concentration range, which is more than predicted by the theoretical calculations. The room temperature value of the damping parameter obtained from ferromagnetic resonance measurements, correcting for extrinsic contributions to the damping, is for the undoped sample 2.1 x 10(-3), which is close to the theoretically calculated Gilbert damping parameter. With 10 at.% Re doping, the damping parameter increases to 7.8 x 10(-3), which is in good agreement with the theoretical value of 7.3 x 10(-3). The increase in damping parameter with Re doping is explained by the increase in the density of states at the Fermi level, mostly contributed by the spin-up channel of Re. Moreover, both experimental and theoretical values for the damping parameter weakly decrease with decreasing temperature.

  • 17.
    Akser, Marielle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Detections of nuclear explosions by triple coincidence2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When a nuclear explosion occurs certain radionuclides are emitted, notably xenon. Due to the fact that xenon is a noble gas, it is hard to contain and can therefore be detected far from the explosion site. There are four isotopes of xenon that are of interest in the detection of a nuclear explosion: 131mXe, 133mXe, 133Xe and 135Xe. By constantly measuring the amount of these isotopes in the air, changes in the concentration in an indication that a nuclear explosion has occurred. In this thesis a detector was modelled in GEANT4 and focuses on one kind of noble gas detector: SAUNA - the Swedish Automatic Unit for Noble gas Acquisition. SAUNA uses the coincidence technique in order to determine the concentration of xenon there is in the air. By using the coincidence technique, it is possible to reduce the impact of the background radiation and therefore increase the efficiency of the detector. 133Xe has a coincidence when it first undergoes beta decay, with an endpoint energy of 346 keV, and then emits a 80 keV gamma particle. 135Xe has also a dual coincidence, a beta decay with an endpoint energy of 910 keV together with a 250 keV gamma-ray. However both these isotopes have a triple coincidence decay that also can be exploited: for 133Xe, a beta particle with endpoint energy of 346 keV, a 30 keV X-ray and a 45 keV conversion electron, while for 135Xe there is instead of the gamma particle a 30 keV X-ray and a 214keV conversion electron that can be emitted together with the beta particle. The 30 keV X-ray together with the beta particle for 133Xe can also be used as a dual coincidence, in that case the conversion electron is ignored. For 133Xe, when a beta particle, a 45 keV conversion electron, and a 30 keV X-ray are emitted, the model was able to detect all three particles in 69.2% ± 0.1 of the cases. However, when only the particles with a detected energy within a 5 keV interval of their generated energies are considered to be in coincidence, then for 133Xe triple coincidence occurs in 22.9% ± 0.2 of the cases. For 135Xe the model was able to detect the triple coincidence (between a beta, 214 keV CE and 30 keV X-ray) in 63.5% ± 0.1 of the cases. This work shows that adding another particle in a coincidence reduces the chance to detect the coincidence. The positive effect of adding another particle in a coincidence is that the minimum detectable concentration of xenon should be smaller. The goal for future detectors should be to make it possible for the detector to take advantage of the triple coincidences but at the same time be also able to use the dual coincidences.

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  • 18.
    Al-Adili, Ali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Measurements of the 234U(n,f) Reaction with a Frisch-Grid Ionization Chamber up to En=5 MeV2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This study on the neutron-induced fission of 234U was carried out at the 7 MV Van de Graaff accelerator of IRMM in Belgium. A Twin Frisch-Grid Ionization Chamber (TFGIC) was used to study 234U(n,f) between En = 0.2 and 5.0 MeV. The reaction is important for fission modelling of the second-chance fission in 235U(n,f). The fission fragment (FF) angular-, energy and mass distributions were determined using the 2E-method highlighting especially the region of the vibrational resonance at En = 0.77 MeV.

    The experiment used both conventional analogue and modern digital acquisition systems in parallel. Several advantages were found in the digital case, especially a successful pile-up correction. The shielding limitations of the Frisch-grid, called "grid-inefficiency", result in an angular-dependent energy signal. The correction of this effect has been a long-standing debate and a solution was recently proposed using the Ramo-Shockley theorem. Theoretical predictions from the latter were tested and verified in this work using two different grids. Also the neutron-emission corrections as a function of excitation energy were investigated. Neutron corrections are crucial for the determination of FF masses. Recent theoretical considerations attribute the enhancement of neutron emission to the heavier fragments exclusively, contrary to the average increase assumed earlier. Both methods were compared and the impact of the neutron multiplicities was assessed. The effects found are significant and highlight the importance of further experimental and theoretical investigation.

    In this work, the strong angular anisotropy of 234U(n,f ) was confirmed. In addition, and quite surprisingly, the mass distribution was found to be angular-dependent and correlated to the vibrational resonances. The anisotropy found in the mass distribution was consistent with an anisotropy in the total kinetic energy (TKE), also correlated to the resonances. The experimental data were parametrized assuming fission modes based on the Multi-Modal Random Neck-Rupture model. The resonance showed an increased yield from the Standard-1 fission mode and a consistent increased TKE. The discovered correlation between the vibrational resonances and the angular-dependent mass distributions for the asymmetric fission modes may imply different outer fission-barrier heights for the two standard modes.

    List of papers
    1. Comparison of digital and analogue data acquisition systems for nuclear spectroscopy
    Open this publication in new window or tab >>Comparison of digital and analogue data acquisition systems for nuclear spectroscopy
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    2010 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 624, no 3, p. 684-690Article in journal (Refereed) Published
    Abstract [en]

    In the present investigation the performance of digital data acquisition (DA) and analogue data acquisition (AA) systems are compared in neutron-induced fission experiments. The DA results are practically identical to the AA results in terms of angular-, energy- and mass-resolution, and both compare very well with literature data. However, major advantages were found with the digital techniques. DA allows for a very efficient αparticle pile-up correction. This is important when considering the accurate measurement of fission-fragment characteristics of highly αactive actinide isotopes relevant for the safe operation of Generation IV reactors and the successful reduction of long-lived radioactive nuclear waste. In case of a strong αemitter, when applying the αparticle pile-up correction, the peak-to-valley ratio of the energy distribution was significantly improved. In addition, DA offers a very flexible expanded off-line analysis and reduces the number of electronic modules drastically, leading to an increased stability against electronic drifts when long measurement times are required.

    Keywords
    Fission, 234-U(n, f), 235-U(n, f), Digital, Analogue, Ionization chambers
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-142438 (URN)10.1016/j.nima.2010.09.126 (DOI)000285370600019 ()
    Available from: 2011-01-14 Created: 2011-01-14 Last updated: 2022-01-28Bibliographically approved
    2. Ambiguities in the grid-inefficiency correction for Frisch-Grid Ionization Chambers
    Open this publication in new window or tab >>Ambiguities in the grid-inefficiency correction for Frisch-Grid Ionization Chambers
    Show others...
    2012 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 673, p. 116-121Article in journal (Refereed) Published
    Abstract [en]

    Ionization chambers with Frisch grids have been very successfully applied to neutron-induced fission-fragment studies during the past 20 years. They are radiation resistant and can be easily adapted to the experimental conditions. The use of Frisch grids has the advantage to remove the angular dependency from the charge induced on the anode plate. However, due to the Grid Inefficiency (GI) in shielding the charges, the anode signal remains slightly angular dependent. The correction for the GI is, however, essential to determine the correct energy of the ionizing particles. GI corrections can amount to a few percent of the anode signal. Presently, two contradicting correction methods are considered in literature. The first method adding the angular-dependent part of the signal to the signal pulse height; the second method subtracting the former from the latter. Both additive and subtractive approaches were investigated in an experiment where a Twin Frisch-Grid Ionization Chamber (TFGIC) was employed to detect the spontaneous fission fragments (FF) emitted by a 252Cf source. Two parallel-wire grids with different wire spacing (1 and 2 mm, respectively), were used individually, in the same chamber side. All the other experimental conditions were unchanged. The 2 mm grid featured more than double the GI of the 1 mm grid. The induced charge on the anode in both measurements was compared, before and after GI correction. Before GI correction, the 2 mm grid resulted in a lower pulse-height distribution than the 1 mm grid. After applying both GI corrections to both measurements only the additive approach led to consistent grid independent pulse-height distributions. The application of the subtractive correction on the contrary led to inconsistent, grid-dependent results. It is also shown that the impact of either of the correction methods is small on the FF mass distributions of 235U(nth, f).

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Grid Inefficiency, 252Cf(sf), Ionization chambers, Fission
    National Category
    Physical Sciences
    Research subject
    Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-172205 (URN)10.1016/j.nima.2011.01.088 (DOI)000301813500016 ()
    Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2017-12-07Bibliographically approved
    3. On the Frisch–Grid signal in ionization chambers
    Open this publication in new window or tab >>On the Frisch–Grid signal in ionization chambers
    Show others...
    2012 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 671, p. 103-107Article in journal (Refereed) Published
    Abstract [en]

    A recent theoretical approach concerning the grid-inefficiency (GI) problem in Twin Frisch–Grid Ionization Chambers was validated experimentally. The experimental verification focused on the induced signal on the anode plate. In this work the investigation was extended by studying the grid signal. The aim was to verify the grid-signal dependency on the grid inefficiency σ. The measurements were made with fission fragments from 252Cf(sf), using two different grids, with 1 and 2 mm wire distances, leading to the GI values: σ=0.031 and σ=0.083, respectively. The theoretical grid signal was confirmed because the detected grid pulse-height distribution was smaller for the larger σ. By applying the additive GI correction approach, the two grid pulse heights were consistent.

    In the second part of the work, the corrected grid signal was used to deduce emission angles of the fission fragments. It is inconvenient to treat the grid signal by means of conventional analogue electronics, because of its bipolarity. Therefore, the anode and grid signals were summed to create a unipolar, angle-dependent pulse height. Until now the so-called summing method has been the well-established approach to deduce the angle from the grid signal. However, this operation relies strongly on an accurate and stable calibration between the two summed signals. By application of digital-signal processing, the grid signal's bipolarity is no longer an issue. Hence one can bypass the intermediate summation step of the two different pre-amplifier signals, which leads to higher stability. In this work the grid approach was compared to the summing method in three cases: 252Cf(sf), 235U(n,f) and 234U(n,f). By using the grid directly, the angular resolution was found equally good in the first case but gave 7% and 20% improvements, respectively, in the latter cases.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Grid inefficiency, Ionization chambers, Summing method
    National Category
    Natural Sciences
    Research subject
    Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-172203 (URN)10.1016/j.nima.2011.12.047 (DOI)000301474600012 ()
    Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2017-12-07Bibliographically approved
    4. Impact of prompt-neutron corrections on final fission-fragment distributions
    Open this publication in new window or tab >>Impact of prompt-neutron corrections on final fission-fragment distributions
    2012 (English)In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 5, p. 054601-Article in journal, Editorial material (Refereed) Published
    Abstract [en]

    Background: One important quantity in nuclear fission is the average number of prompt neutrons emitted from the fission fragments, the prompt neutron multiplicity, ν . The total number of prompt fission neutrons, νtot, increases with increasing incident neutron energy. The prompt-neutron multiplicity is also a function of the fragment mass and the total kinetic energy of the fragmentation. Those data are only known in sufficient detail for a few thermal-neutron-induced fission reactions on, for example, 233,235U and 239Pu. The enthralling question has always been asked how the additional excitation energy is shared between the fission fragments. The answer to this question is important in the analysis of fission-fragment data taken with the double-energy technique. Although in the traditional approach the excess neutrons are distributed equally across the mass distribution, a few experiments showed that those neutrons are predominantly emitted by the heavy fragments.

    Purpose: We investigated the consequences of the ν(A,TKE,En) distribution on the fission fragment observables.

    Methods: Experimental data obtained for the 234U(n, f) reaction with a Twin Frisch Grid Ionization Chamber, were analyzed assuming two different methods for the neutron evaporation correction. The effect of the two different methods on the resulting fragment mass and energy distributions is studied.

    Results: We found that the preneutron mass distributions obtained via the double-energy technique become slightly more symmetric, and that the impact is larger for postneutron fission-fragment distributions. In the most severe cases, a relative yield change up to 20–30% was observed.

    Conclusions: We conclude that the choice of the prompt-neutron correction method has strong implications on the understanding and modeling of the fission process and encourages new experiments to measure fission fragments in coincidence with prompt fission neutrons. Even more, the correct determination of postneutron fragment yields has an impact on the reliable assessment of the nuclear waste inventory, as well as on the correct prediction of delayed neutron precursor yields.

    Keywords
    Fission, Neutron
    National Category
    Subatomic Physics
    Research subject
    Physics with specialization in Applied Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-185076 (URN)10.1103/PhysRevC.86.054601 (DOI)000310685400003 ()
    Available from: 2012-11-21 Created: 2012-11-19 Last updated: 2017-12-07Bibliographically approved
    5. Indication of anisotropic TKE and mass emission in 234U(n,f)
    Open this publication in new window or tab >>Indication of anisotropic TKE and mass emission in 234U(n,f)
    2012 (English)In: Physics Procedia / [ed] Stephan Oberstedt, 2012, p. 158-164Conference paper, Oral presentation only (Refereed)
    Abstract [en]

    The neutron-induced fission of 234U has been studied for neutron energies ranging from 200 keV to 5 MeV. Special focus was put around the prominent vibrational resonance in the sub-barrier region around 800 keV incident neutron energy. The aim was to investigate the fission fragment (FF) characteristics and search for fluctuations in energy and mass distributions. The strong angular anisotropy in the case of 234U(n,f) was verified and correlations with changes in energy and mass distributions were found. The TKE around the resonance increases contrary to earlier literature data. Furthermore, the TKE and mass distribution were found to be dependent on emission angle. At the resonance, the TKE was smallest near the 0° emission of the FF. This effect was consistent and coherent with a change in the mass distribution around the resonance. The mass distribution was observed to be less asymmetric near 0° emission. From a fitting analysis based on the Multi-Modal Random Neck-Rupture (MMRNR) model, we found the yield of the standard-1 mode increasing around the resonance. Because the TKE is increasing at larger angles and the mass distribution becomes more symmetric also at larger angles, we conclude that this behavior is due to an increase of the standard-1 mode at these larger angles. Based on the formalism of MMRNR, such difference in angular distribution may be an indication of a different outer barrier height for the standard-1 and standard-2 modes.

    Series
    Physics Procedia, ISSN 1875-3892 ; 31
    Keywords
    Fission, U-234, Neutron
    National Category
    Subatomic Physics
    Research subject
    Physics with specialization in Applied Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-185303 (URN)10.1016/j.phpro.2012.04.021 (DOI)000309656300020 ()
    Conference
    GAMMA-1 Emission of Prompt Gamma-Rays in Fission and Related Topics, nov 22-21, 2011, Navi Sad, Serbia
    Available from: 2012-11-21 Created: 2012-11-21 Last updated: 2013-02-11
    6. First evidence of correlation between vibrational resonances and an anisotropy in the fission mass distribution
    Open this publication in new window or tab >>First evidence of correlation between vibrational resonances and an anisotropy in the fission mass distribution
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    In this work we present evidence of anisotropic emission of fragment masses in 234U(n,f). The discovered mass anisotropy is correlated with the prominent vibrational resonances at En = 0.5 and 0.77 MeV and coincides with a verified strong angular anisotropy. From the outcome of this experimental work one may infer unequal fission barrier heights for different degrees of fission asymmetry.

    Keywords
    U-234, Fission, Neutron, Resonance, Anisotropy
    National Category
    Subatomic Physics
    Research subject
    Physics with specialization in Applied Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-185307 (URN)
    Available from: 2012-11-28 Created: 2012-11-21 Last updated: 2013-02-11
    7. Fragment mass-, kinetic energy- and angular distributions for 234U(n, f) at incident neutron energies from En = 0.2 to 5.0 MeV
    Open this publication in new window or tab >>Fragment mass-, kinetic energy- and angular distributions for 234U(n, f) at incident neutron energies from En = 0.2 to 5.0 MeV
    Show others...
    2016 (English)In: Physical review C, ISSN 2469-9985, Vol. 93, no 3, article id 034603Article in journal (Refereed) Published
    Abstract [en]

    This work investigates the neutron-induced fission of U-234 and the fission-fragment properties for neutron energies between E-n = 0.2 and 5.0 MeV with a special highlight on the prominent vibrational resonance at E-n = 0.77 MeV. Angular, energy, and mass distributions were determined based on the double-energy technique by means of a twin Frisch-grid ionization chamber. The experimental data are parametrized in terms of fission modes based on the multimodal random neck-rupture model. The main results are a verified strong angular anisotropy and fluctuations in the energy release as a function of incident-neutron energy.

    Keywords
    234U, Neutron, Fission, Resonance, Frisch-Grid
    National Category
    Subatomic Physics
    Research subject
    Physics with specialization in Applied Nuclear Physics
    Identifiers
    urn:nbn:se:uu:diva-185332 (URN)10.1103/PhysRevC.93.034603 (DOI)000371409000006 ()
    Available from: 2012-11-29 Created: 2012-11-22 Last updated: 2016-04-13Bibliographically approved
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  • 19.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Alhassan, Erwin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Helgesson, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Koning, Arjan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Nucl Res & Consultancy Grp NRG, Petten, Netherlands.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fission Activities of the Nuclear Reactions Group in Uppsala2015In: Scientific Workshop on Nuclear Fission Dynamics and the Emission of Prompt Neutrons and Gamma Rays, THEORY-3 / [ed] Franz-Josef Hambsch and Nicolae Carjan, 2015, p. 145-149Conference paper (Refereed)
    Abstract [en]

    This paper highlights some of the main activities related to fission of the nuclear reactions group at Uppsala University. The group is involved for instance in fission yield experiments at the IGISOL facility, cross-section measurements at the NFS facility, as well as fission dynamics studies at the IRMM JRC-EC. Moreover, work is ongoing on the Total Monte Carlo (TMC) methodology and on including the GEF fission code into the TALYS nuclear reaction code. Selected results from these projects are discussed.

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  • 20.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gao, Zhihao
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Isomer yields in nuclear fission2021In: EPJ Web of Conferences, E-ISSN 2100-014X, Vol. 256, article id 00002Article in journal (Refereed)
    Abstract [en]

    The generation of angular momentum in the fission process is still an open question. To shed light on this topic, we started a series of measurements at the IGISOL-JYFLTRAP facility in Finland. Highprecision measurements of isomeric yield ratios (IYR) are performed with a Penning trap, partly with the aim to extract average root-mean-square (rms) quantities of fragment spin distributions. The newly installed Phase-Imaging Ion-Cyclotron Resonance (PI-ICR) technique allows the separation of masses down to tens of keV, which is suffcient to disentangle many isomers. In this paper, we first summarize the previous measurements on the neutron and proton-induced fission of uranium and thorium, e.g. the odd cadmium and indium isotopes (119 ≤ A ≤ 127). The measurements revealed systematic trends as function of mass number, which stimulated further exploration. A recent measurement was performed at IGISIOL and several new IYR data will soon be published, for the first time. Secondly, we employ the TALYS nuclear-reaction code to model one of the newly measured isomer yields. Detailed GEF and TALYS calculations are discussed for the fragment angular momentum distribution in 134I.

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  • 21.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, F. -J
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, S.
    Sensitivity of Measured Fission Yields on Prompt-neutron Corrections2014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. 342-345Article in journal (Refereed)
    Abstract [en]

    Although the number of emitted prompt neutrons from the fission fragments increases as a function of excitation energy, it is not fully understood whether the increase in (nu) over bar (A) as a function of E-n is mass dependent. The share of excitation energies among the fragments is still under debate, but there are reasons to believe that the excess in neutron emission originates only from the heavy fragments, leaving (nu) over bar (light) (A) almost unchanged. We have investigated the consequences of a mass-dependent increase in (nu) over bar (A) on the final mass and energy distributions. The analysis have been performed on experimentally measured data on U-234(n, f). The assumptions concerning (nu) over bar (A) are essential when analysing measurements based on the 2E-technique, and impact significantly on the measured observables. For example, the post-neutron emission mass yield distribution revealed changes up to 10-30 %. The outcome of this work pinpoints the urgent need to determine (nu) over bar (A) experimentally, and in particular, how (nu) over bar (A) changes as a function of incident neutron energy. Many fission yields in the data libraries could be largely affected, since their analysis is based on a different assumption concerning the neutron emission.

  • 22.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, F.-J.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, S.
    Corrections of Prompt-neutron Emission in Fission-fragment Experiments2013In: Physics Procedia, Vol 47, 2013, 2013, p. 131-136Conference paper (Refereed)
    Download full text (pdf)
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  • 23.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, F.-J.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, S.
    Sensitivity of measured fission yields on prompt-neutron corrections2014Conference paper (Refereed)
  • 24.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM JRC EC.
    Bencardino, Raffaele
    IRMM JRC EC.
    Oberstedt, Stephan
    IRMM JRC EC.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ambiguities in the grid-inefficiency correction for Frisch-Grid Ionization Chambers2012In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 673, p. 116-121Article in journal (Refereed)
    Abstract [en]

    Ionization chambers with Frisch grids have been very successfully applied to neutron-induced fission-fragment studies during the past 20 years. They are radiation resistant and can be easily adapted to the experimental conditions. The use of Frisch grids has the advantage to remove the angular dependency from the charge induced on the anode plate. However, due to the Grid Inefficiency (GI) in shielding the charges, the anode signal remains slightly angular dependent. The correction for the GI is, however, essential to determine the correct energy of the ionizing particles. GI corrections can amount to a few percent of the anode signal. Presently, two contradicting correction methods are considered in literature. The first method adding the angular-dependent part of the signal to the signal pulse height; the second method subtracting the former from the latter. Both additive and subtractive approaches were investigated in an experiment where a Twin Frisch-Grid Ionization Chamber (TFGIC) was employed to detect the spontaneous fission fragments (FF) emitted by a 252Cf source. Two parallel-wire grids with different wire spacing (1 and 2 mm, respectively), were used individually, in the same chamber side. All the other experimental conditions were unchanged. The 2 mm grid featured more than double the GI of the 1 mm grid. The induced charge on the anode in both measurements was compared, before and after GI correction. Before GI correction, the 2 mm grid resulted in a lower pulse-height distribution than the 1 mm grid. After applying both GI corrections to both measurements only the additive approach led to consistent grid independent pulse-height distributions. The application of the subtractive correction on the contrary led to inconsistent, grid-dependent results. It is also shown that the impact of either of the correction methods is small on the FF mass distributions of 235U(nth, f).

  • 25.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM JRC EC .
    Bencardino, Raffaele
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, Stephan
    Zeynalov, Shakir
    JINR.
    On the Frisch–Grid signal in ionization chambers2012In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 671, p. 103-107Article in journal (Refereed)
    Abstract [en]

    A recent theoretical approach concerning the grid-inefficiency (GI) problem in Twin Frisch–Grid Ionization Chambers was validated experimentally. The experimental verification focused on the induced signal on the anode plate. In this work the investigation was extended by studying the grid signal. The aim was to verify the grid-signal dependency on the grid inefficiency σ. The measurements were made with fission fragments from 252Cf(sf), using two different grids, with 1 and 2 mm wire distances, leading to the GI values: σ=0.031 and σ=0.083, respectively. The theoretical grid signal was confirmed because the detected grid pulse-height distribution was smaller for the larger σ. By applying the additive GI correction approach, the two grid pulse heights were consistent.

    In the second part of the work, the corrected grid signal was used to deduce emission angles of the fission fragments. It is inconvenient to treat the grid signal by means of conventional analogue electronics, because of its bipolarity. Therefore, the anode and grid signals were summed to create a unipolar, angle-dependent pulse height. Until now the so-called summing method has been the well-established approach to deduce the angle from the grid signal. However, this operation relies strongly on an accurate and stable calibration between the two summed signals. By application of digital-signal processing, the grid signal's bipolarity is no longer an issue. Hence one can bypass the intermediate summation step of the two different pre-amplifier signals, which leads to higher stability. In this work the grid approach was compared to the summing method in three cases: 252Cf(sf), 235U(n,f) and 234U(n,f). By using the grid directly, the angular resolution was found equally good in the first case but gave 7% and 20% improvements, respectively, in the latter cases.

  • 26.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM - JRC - EC.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, Stephan
    IRMM - JRC - EC.
    Indication of anisotropic TKE and mass emission in 234U(n,f)2012In: Physics Procedia / [ed] Stephan Oberstedt, 2012, p. 158-164Conference paper (Refereed)
    Abstract [en]

    The neutron-induced fission of 234U has been studied for neutron energies ranging from 200 keV to 5 MeV. Special focus was put around the prominent vibrational resonance in the sub-barrier region around 800 keV incident neutron energy. The aim was to investigate the fission fragment (FF) characteristics and search for fluctuations in energy and mass distributions. The strong angular anisotropy in the case of 234U(n,f) was verified and correlations with changes in energy and mass distributions were found. The TKE around the resonance increases contrary to earlier literature data. Furthermore, the TKE and mass distribution were found to be dependent on emission angle. At the resonance, the TKE was smallest near the 0° emission of the FF. This effect was consistent and coherent with a change in the mass distribution around the resonance. The mass distribution was observed to be less asymmetric near 0° emission. From a fitting analysis based on the Multi-Modal Random Neck-Rupture (MMRNR) model, we found the yield of the standard-1 mode increasing around the resonance. Because the TKE is increasing at larger angles and the mass distribution becomes more symmetric also at larger angles, we conclude that this behavior is due to an increase of the standard-1 mode at these larger angles. Based on the formalism of MMRNR, such difference in angular distribution may be an indication of a different outer barrier height for the standard-1 and standard-2 modes.

  • 27.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM-JRC-EC.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, Stephan
    IRMM-JRC-EC.
    Possible anisotropy in the emission of fission fragments2012In: Conference: 13th international conference on nuclear reaction mechanisms, At Villa Monastero, Varenna, Italy, Volume: pp. 223-225 / [ed] F. Cerutti, 2012, p. 223-225Conference paper (Refereed)
    Abstract [en]

    This study on 234U(n,f) focused on the vibrational resonance at the incident neutron energy En=770 keV. Due to the strong angular anisotropy, Fluctuations of the fission fragment (FF) properties were predicted. The bipolar angular anisotropy was verified in this work and a possible new correlation to anisotropic FF emission has been observed. The mass distribution was found to have the biggest difference in asymmetry, at the vibrational resonance and was less asymmetric in emission along the axis of the beam direction. A corresponding anisotropy in the total kinetic energy was also observed. The observed effect was consistent with the change in the mass distribution. At last, the experimental data were fitted based on the Multi-Modal Random Neck Rupture (MM-RNR) model. The yield of the standard-1 mode was found to increase at the resonance.

  • 28.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM - JRC - EC.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stephan, Oberstedt
    IRMM - JRC - EC.
    First evidence of correlation between vibrational resonances and an anisotropy in the fission mass distributionManuscript (preprint) (Other academic)
    Abstract [en]

    In this work we present evidence of anisotropic emission of fragment masses in 234U(n,f). The discovered mass anisotropy is correlated with the prominent vibrational resonances at En = 0.5 and 0.77 MeV and coincides with a verified strong angular anisotropy. From the outcome of this experimental work one may infer unequal fission barrier heights for different degrees of fission asymmetry.

  • 29.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    IRMM - JRC - EC.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stephan, Oberstedt
    IRMM - JRC - EC.
    Impact of prompt-neutron corrections on final fission-fragment distributions2012In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 86, no 5, p. 054601-Article in journal (Refereed)
    Abstract [en]

    Background: One important quantity in nuclear fission is the average number of prompt neutrons emitted from the fission fragments, the prompt neutron multiplicity, ν . The total number of prompt fission neutrons, νtot, increases with increasing incident neutron energy. The prompt-neutron multiplicity is also a function of the fragment mass and the total kinetic energy of the fragmentation. Those data are only known in sufficient detail for a few thermal-neutron-induced fission reactions on, for example, 233,235U and 239Pu. The enthralling question has always been asked how the additional excitation energy is shared between the fission fragments. The answer to this question is important in the analysis of fission-fragment data taken with the double-energy technique. Although in the traditional approach the excess neutrons are distributed equally across the mass distribution, a few experiments showed that those neutrons are predominantly emitted by the heavy fragments.

    Purpose: We investigated the consequences of the ν(A,TKE,En) distribution on the fission fragment observables.

    Methods: Experimental data obtained for the 234U(n, f) reaction with a Twin Frisch Grid Ionization Chamber, were analyzed assuming two different methods for the neutron evaporation correction. The effect of the two different methods on the resulting fragment mass and energy distributions is studied.

    Results: We found that the preneutron mass distributions obtained via the double-energy technique become slightly more symmetric, and that the impact is larger for postneutron fission-fragment distributions. In the most severe cases, a relative yield change up to 20–30% was observed.

    Conclusions: We conclude that the choice of the prompt-neutron correction method has strong implications on the understanding and modeling of the fission process and encourages new experiments to measure fission fragments in coincidence with prompt fission neutrons. Even more, the correct determination of postneutron fragment yields has an impact on the reliable assessment of the nuclear waste inventory, as well as on the correct prediction of delayed neutron precursor yields.

  • 30.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    European Commiss, Joint Res Ctr, IRMM, B-2440 Geel, Belgium.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stephan, Oberstedt
    European Commiss, Joint Res Ctr, IRMM, B-2440 Geel, Belgium.
    Vidali, M.
    European Commiss, Joint Res Ctr, IRMM, B-2440 Geel, Belgium.
    Fragment mass-, kinetic energy- and angular distributions for 234U(n, f) at incident neutron energies from En = 0.2 to 5.0 MeV2016In: Physical review C, ISSN 2469-9985, Vol. 93, no 3, article id 034603Article in journal (Refereed)
    Abstract [en]

    This work investigates the neutron-induced fission of U-234 and the fission-fragment properties for neutron energies between E-n = 0.2 and 5.0 MeV with a special highlight on the prominent vibrational resonance at E-n = 0.77 MeV. Angular, energy, and mass distributions were determined based on the double-energy technique by means of a twin Frisch-grid ionization chamber. The experimental data are parametrized in terms of fission modes based on the multimodal random neck-rupture model. The main results are a verified strong angular anisotropy and fluctuations in the energy release as a function of incident-neutron energy.

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  • 31.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wiberg, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ion counting efficiencies at the IGISOL facility2014Report (Other academic)
    Abstract [en]

    At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.

  • 32.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattias, Lantz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, Dmitry
    Department of Physics, FI-40014 University of Jyväskylä, Finland.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moore, Iain
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Penttilä, Heikki
    Department of Physics, FI-40014 University of Jyväskylä, Finland.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wiberg, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simulations of the fission-product stopping efficiency in IGISOL2015In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, no 59, p. 1-7Article in journal (Refereed)
    Abstract [en]

    At the Jyväskylä Ion Guide Isotope Separator On-Line (IGISOL) facility, independent fission yields are measured employing the Penning-trap technique. Fission products are produced, e.g. by impinging protons on a uranium target, and are stopped in a gas-filled chamber. The products are collected by a flow of He gas and guided through a mass separator to a Penning trap, where their masses are identified. This work investigates how fission-product properties, such as mass and energy, affect the ion stopping efficiency in the gas cell. The study was performed using the Geant4 toolkit and the SRIM code. The main results show a nearly mass-independent ion stopping with regard to the wide spread of ion masses and energies, with a proper choice of uranium target thickness. Although small variations were observed, in the order of 5%, the results are within the systematic uncertainties of the simulations. To optimize the stopping efficiency while reducing the systematic errors, different experimental parameters were varied; for instance material thicknesses and He gas pressure. Different parameters influence the mass dependence and could alter the mass dependencies in the ion stopping efficiency.

  • 33.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrio, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    European Commiss, Joint Res Ctr, Directorate G2, Geel, Belgium..
    Gook, Alf
    European Commiss, Joint Res Ctr, Directorate G2, Geel, Belgium..
    Oberstedt, Stephan
    European Commiss, Joint Res Ctr, Directorate G2, Geel, Belgium..
    Fregeau, Marc Olivier
    GANIL CEA DRF CNRS IN2P3, Caen, France..
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Vidali, Marzio
    European Commiss, Joint Res Ctr, Directorate G2, Geel, Belgium..
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Studying fission neutrons with 2E-2v and 2E2018In: SCIENTIFIC WORKSHOP ON NUCLEAR FISSION DYNAMICS AND THE EMISSION OF PROMPT NEUTRONS AND GAMMA RAYS (THEORY-4) / [ed] Hambsch, FJ Carjan, N Rusko, I, 2018, article id UNSP 00002Conference paper (Refereed)
    Abstract [en]

    This work aims at measuring prompt-fission neutrons at different excitation energies of the nucleus. Two independent techniques, the 2E-2v and the 2E techniques, are used to map the characteristics of the mass-dependent prompt fission neutron multiplicity, 7(A), when the excitation energy is increased. The VERDI 2E-2v spectrometer is being developed at JRC-GEEL. The Fission Fragment (FF) energies are measured using two arrays of 16 silicon (Si) detectors each. The FFs velocities are obtained by time-of-flight, measured between micro-channel plates (MCP) and Si detectors. With MCPs placed on both sides of the fission source, VERDI allows for independent timing measurements for both fragments. Cf-252(sf) was measured and the present results revealed particular features of the 2E-2v technique. Dedicated simulations were also performed using the GEF code to study important aspects of the 2E-2v technique. Our simulations show that prompt neutron emission has a non-negligible impact on the deduced fragment data and affects also the shape of 17(A). Geometrical constraints lead to a total-kinetic energy-dependent detection efficiency. The 2E technique utilizes an ionization chamber together with two liquid scintillator detectors. Two measurements have been performed, one of Cf-252(sf) and another one of thermal-neutron induced fission in U-235(n,f). Results from Cf-252(sf) are reported here.

  • 34.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Extraction of angular momenta from isomeric yield ratios - assessment of TALYS as a fission fragment de-excitation codeManuscript (preprint) (Other academic)
  • 35.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Extraction of angular momenta from isomeric yield ratios: Employing TALYS to de-excite primary fission fragments2019In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, no 4, article id 61Article in journal (Refereed)
    Abstract [en]

    The generation of angular momentum in fission is difficult to model, in particular at higher excitation energies where data are scarce. Isomeric yield ratios (IYR) play an important role in deducing angular momentum properties of fission fragments (FF), albeit this requires some assumptions and simplifications. To estimate FF angular momentum, fission codes can be used to calculate IYRs and compare them to experimental data. Such measurements have systematically been performed at the IGISOL facility using novel experimental techniques. In conjunction, a new method has been developed to infer the angular momentum of the primary FF using the nuclear reaction code TALYS. In this work, we evaluate this new method by comparing our TALYS calculations with values found in the literature and with results from the GEF fission code, for a few well-studied reactions. The overall results show a consistent performance of TALYS and GEF, as well as of many reported literature values. However, some deviations were found, possibly pinpointing the need to re-examine some of the reported literature values. A sensitivity analysis was also performed, in which the role of excitation energy, neutron emission, discrete level structure and level density models were studied. Finally, the role of multiple chance fission, of relevance for the reactions studied at IGISOL, is discussed. Some literature data for this reaction were also re-analyzed using TALYS, revealing significant differences.

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  • 36.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Employing TALYS to deduce angular momentum rootmean-square values, J(rms), in fission fragments2020In: ND 2019: International Conference On Nuclear Data For Science And Technology / [ed] Ge, Z; Shu, N; Chen, Y; Wang, W; Zhang, H, E D P SCIENCES , 2020, article id 03019Conference paper (Refereed)
    Abstract [en]

    Fission fragments exhibit large angular momenta J, which constitutes a challenge for fission models to fully explain. Systematic measurements of isomeric yield ratios (IYR) are needed for basic nuclear reaction physics and nuclear applications, especially as a function of mass number and excitation energy. One goal is to improve the current understanding of the angular momentum generation and sharing in the fission process. To do so, one needs to improve the modeling of nuclear de-excitation. In this work, we have used the TALYS nuclear-reaction code to relax excited fission fragments and to extract root-mean-square (rms) values of initial spin distributions, after comparison with experimentally determined IYRs. The method was assessed by a comparative study on Cf-252(sf) and (235)(nth,f). The results show a consistent performance of TALYS, both in comparison to reported literature values and to other fission codes. A few discrepant Jrms values were also found. The discrepant literature values could need a second consideration as they could possibly be caused by outdated models. Our TALYS method will be refined to better comply with contemporary sophisticated models and to reexamine older deduced values in literature.

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  • 37.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, F. -J
    EC JRC Inst Reference Mat & Measurements IRMM, Geel, Belgium.
    Gook, A.
    EC JRC Inst Reference Mat & Measurements IRMM, Geel, Belgium..
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, S.
    EC JRC Inst Reference Mat & Measurements IRMM, Geel, Belgium..
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Vidali, M.
    EC JRC Inst Reference Mat & Measurements IRMM, Geel, Belgium..
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Analysis of prompt fission neutrons in U-235(nth,f) and fission fragment distributions for the thermal neutron induced fission of U-2342016In: CNR*15 - 5th International Workshop On Compound-Nuclear Reactions And Related Topics, 2016, article id 01007Conference paper (Refereed)
    Abstract [en]

    This paper presents the ongoing analysis of two fission experiments. Both projects are part of the collaboration between the nuclear reactions group at Uppsala and the JRC-IRMM. The first experiment deals with the prompt fission neutron multiplicity in the thermal neutron induced fission of U-235(n,f). The second, on the fission fragment properties in the thermal fission of U-234(n,f). The prompt fission neutron multiplicity has been measured at the JRC-IRMM using two liquid scintillators in coincidence with an ionization chamber. The first experimental campaign focused on U-235(nth,f) whereas a second experimental campaign is foreseen later for the same reaction at 5.5 MeV. The goal is to investigate how the so-called saw-tooth shape changes as a function of fragment mass and excitation energy. Some harsh experimental conditions were experienced due to the large radiation background. The solution to this will be discussed along with preliminary results. In addition, the analysis of thermal neutron induced fission of U-234(n,f) will be discussed. Currently analysis of data is ongoing, originally taken at the ILL reactor. The experiment is of particular interest since no measurement exist of the mass and energy distributions for this system at thermal energies. One main problem encountered during analysis was the huge background of U-235(nth, f). Despite the negligible isotopic traces in the sample, the cross section difference is enormous. Solution to this parasitic background will be highlighted.

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  • 38.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hambsch, Franz-Josef
    European Commission, Joint Research Centre, Directorate G, Geel, Belgium.
    Göök, Alf
    European Commission, Joint Research Centre, Directorate G, Geel, Belgium.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Oberstedt, Stephan
    European Commission, Joint Research Centre, Directorate G, Geel, Belgium.
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sundén, Erik A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Vidali, Marzio
    European Commission, Joint Research Centre, Directorate G, Geel, Belgium.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Neutron-multiplicity experiments for enhanced fission modelling2017In: EPJ Web of Conferences / [ed] Plompen, A.; Hambsch, FJ.; Schillebeeckx, P.; Mondelaers, W.; Heyse, J.; Kopecky, S.; Siegler, P.; Oberstedt, S., 2017, Vol. 146, article id 04056Conference paper (Refereed)
    Abstract [en]

    The nuclear de-excitation process of fission fragments (FF) provides fundamental information for the understanding of nuclear fission and nuclear structure in neutron-rich isotopes. The variation of the prompt-neutron multiplicity, ν(A), as a function of the incident neutron energy (En) is one of many open questions. It leads to significantly different treatments in various fission models and implies that experimental data are analyzed based on contradicting assumptions. One critical question is whether the additional excitation energy (Eexc) is manifested through an increase of ν(A) for all fragments or for the heavy ones only. A systematic investigation of ν(A) as a function of En has been initiated. Correlations between prompt-fission neutrons and fission fragments are obtained by using liquid scintillators in conjunction with a Frisch-grid ionization chamber. The proof-of-principle has been achieved on the reaction 235U(nth,f) at the Van De Graff (VdG) accelerator of the JRC-Geel using a fully digital data acquisition system. Neutrons from 252Cf(sf) were measured separately to quantify the neutron-scattering component due to surrounding shielding material and to determine the intrinsic detector efficiency. Prelimenary results on ν(A) and spectrum in correlation with FF properties are presented.

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  • 39.
    Al-Adili, Ali
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Göök, A.
    Hambsch, F.-J.
    Oberstedt, S.
    Vidali, M.
    Prompt fission neutron yields in thermal fission of 235U and spontaneous fission of 252Cf2020In: Physical Review C: Covering Nuclear Physics, ISSN 2469-9985, E-ISSN 2469-9993, Vol. 102, no 6, article id 064610Article in journal (Refereed)
    Abstract [en]

    Background: The sharing of excitation energy between the fission fragments is one of the key issues in studying nuclear fission. One way to address this is by studying prompt-fission neutron multiplicities as a function of other fission observables such as the mass, ¯ν(A). These are vital benchmark data for both fission and nuclear deexcitation models, putting constrains on the fragment excitation energy and hence on the competing prompt neutron/γ-ray emission. Despite numerous detailed studies, recent measurements done at JRC-Geel with the SCINTIA array in the epithermal region show surprisingly strong discrepancies to earlier thermal fission data and the Wahl systematics.

    Purpose: The purpose was to perform measurements of the prompt-fission neutron multiplicity, as a function of fragment mass and total kinetic energy (TKE), in 235U(nth,f) and 252Cf(sf), to verify and extend the SCINTIA results. Another goal was to validate the analysis methods, and prepare for planned investigations at excitation energies up to 5.5 MeV.

    Methods: The experiments were conducted at the former 7 MV Van de Graaff facility in JRC-Geel, using a Twin Frisch-Grid Ionization Chamber and two liquid scintillation detectors. A neutron beam with an average energy of 0.5 MeV was produced via the 7Li(p,n) reaction. The neutrons were thermalized by a 12 cm thick block of paraffin. Digital data acquisition systems were utilized. Comprehensive simulations were performed to verify the methodology and to investigate the role of the mass and energy resolution on measured ¯ν(A) and ¯ν(TKE) values. The simulation results also revealed that the ∂¯ν(A)/∂A and ∂¯TKE/∂¯ν are affected by the mass and energy resolution. However, the effect is small for the estimated resolutions of this work. Detailed Fluka simulations were performed to calculate the fraction of thermal neutron-induced fission, which was estimated to be about 98%.

    Results: The experimental results on ¯ν(A) are in good agreement with earlier data for 252Cf(sf). For 235U(nth,f), the ¯ν(A) data is very similar to the data obtained with SCINTIA, and therefore we verify these disclosed discrepancies to earlier thermal data and to the Wahl evaluation. The experimental results on ¯ν(TKE) are also in agreement with the data at epithermal energies. For 252Cf(sf) a slope value of ∂¯TKE/∂¯ν=(−12.9±0.2)MeV/n was obtained. For 235U(nth,f) the value is (−12.0±0.1)MeV/n. Finally, the neutron spectrum in the center-of-mass system was derived and plotted as a function of fragment mass.

    Conclusions: This work clearly proves the lack of accurate correlation between fission fragment and neutron data even in the best-studied reactions. The new results highlight the need of a new evaluation of the prompt-fission multiplicity for 235U(nth,f).

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  • 40. Alam, Syed Bahauddin
    et al.
    Almutairi, B.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. CEA Cadarache.
    Goodwin, C. S.
    Ameri, S. A.
    Convergence Studies Using Method Of Characteristics Solver For The Reduced-Moderation Water Reactor Model.2018Conference paper (Other academic)
  • 41.
    Alam, Syed Bahauddin
    et al.
    CEA Cadarache.
    Almutairi, B.
    Ridwan, T.
    Cambridge Univeristy.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Goodwin, C.
    Uncertainty Quantification on Core Input Parameter for SFR Core Using Polynomial Chaos2019In: Transactions of the American Nuclear Society, ISSN 0003-018X, Vol. 120, no 1, p. 871-874Article in journal (Refereed)
  • 42.
    Alam, Syed Bahauddin
    et al.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Almutairi, Bader
    Missouri S&T, Dept Min & Nucl Engn, Rolla, MO USA.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tanim, Shakhawat H.
    Univ S Florida, Sch Geosci, Tampa, FL 33620 USA.
    Jaradat, Safwan
    Higher Coll Technol, Abu Dhabi, U Arab Emirates.
    Goodwin, Cameron S.
    Rhode Isl Atom Energy Commiss, Narragansett, RI USA.
    Atkinson, Kirk D.
    Univ Ontario, Inst Technol, Oshawa, ON, Canada.
    Parks, Geoffrey T.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Neutronic feasibility of civil marine small modular reactor core using mixed D-2 O+ H2O coolant2020In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 359, article id 110449Article in journal (Refereed)
    Abstract [en]

    In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not to use highly enriched uranium, but it is then a challenge to achieve long core lifetime while maintaining reactivity control and acceptable power distributions in the core. The objective of this study is to design a civil marine core type of single batch small modular reactor (SMR) with low enriched uranium (LEU) (20% U-235 enrichment), a soluble-boron-free (SBF) and using mixed D-2 O+ H2O coolant for operation period over a 20 years life at 333 MWth. Changing the coolant properties is the way to alter the neutron energy spectrum in order to achieve a self-sustaining core design of higher burnup. Two types of LEU fuels were used in this study: micro-heterogeneous ThO2-UO2 duplex fuel (18% U-235 enriched) and all-UO2 fuel (15% U-235 enriched). 2D Assembly designs are developed using WIMS and 3D whole-core model is developed using PANTHER code. The duplex option shows greater promise in the final burnable poison design with high thickness ZrB2 integral fuel burnable absorber (IFBA) while maintaining low, stable reactivity with minimal burnup penalty. For the final poison design with ZrB2, the duplex contributes (similar to)2.5% more initial reactivity suppression, although the all-UO2 design exhibits lower reactivity swing. Three types of candidate control rod materials: hafnium, boron carbide (B4C) and 80% silver + 15% indium + 5% cadmium (Ag-In-Cd) are examined and duplex fuel exhibits higher control rod worth with the candidate materials. B4C shows the greatest control reactivity worth for both the candidate fuels, providing (similar to)3% higher control rod worth for duplex fuel than all-UO2. Finally, 3D whole-core results from PANTHER show that the use of the mixed coolant contributes to (similar to)21.5 years core life, which is a (similar to)40% increase in core life compared to H2O coolant ((similar to)15.5 years) while using the same fuel candidates and fissile enrichment. The mixed coolant provides excellent core lifetimes comparable to those of HEU military naval vessels ((similar to)25 years vs. (similar to)21.5 years) while utilizing LEU candidate fuels.

  • 43.
    Alam, Syed Bahauddin
    et al.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Almutairi, Bader
    Missouri S&T, Dept Nucl Engn, Rolla, MO USA.
    Ridwan, Tuhfatur
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Goodwin, Cameron S.
    Rhode Isl Nucl Sci Ctr, 16 Reactor Rd, Narragansett, RI 02882 USA.
    Atkinson, Kirk D.
    Univ Ontario Inst Technol, 2000 Simcoe St North, Oshawa, ON L1G 0C5, Canada.
    Parks, Geoffrey T.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Neutronic investigation of alternative & composite burnable poisons for the soluble-boron-free and long life civil marine small modular reactor cores2019In: Scientific Reports, E-ISSN 2045-2322, Vol. 9, article id 19591Article in journal (Refereed)
    Abstract [en]

    Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to combat global warming, and that also includes the commercial freight shipping sector. In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not use soluble boron for reactivity control, but it is then a challenge to achieve an adequate shutdown margin throughout the core life while maintaining reactivity control and acceptable power distributions in the core. High-thickness ZrB2 150 mu m Integral Fuel Burnable Absorber (IFBA) is an excellent burnable poison (BP) candidate for long life soluble-boron-free core. However, in this study, we want to minimize the use of 150 mu m IFBA since B-10 undergoes an (n, alpha) capture reaction, and the resulting helium raises the pressure within the plenum and in the cladding. Therefore, we have considered several alternative and novel burnable BP design strategies to minimize the use of IFBA for reactivity control in this study: (Case 1) a composite BP: gadolinia (Gd2O3) or erbia (Er2O3) with 150 mu m thickness ZrB2 IFBA; (Case 2) Pu-240 or Am-241 mixed homogeneously with the fuel; and (Case 3) another composite BP: Pu-240 or Am-241 with 150 mu m thickness ZrB2 IFBA. The results are compared against those for a high-thickness 150 mu m 25 IFBA pins design from a previous study. The high-thickness 150 mu m 25 IFBA pins design is termed the "IFBA-only" BP design throughout this study. We arrive at a design using 15% U-235 fuel loaded into 13 x 13 assemblies with Case 3 BPs (IFBA+Pu-240 or IFBA+Am-241) for reactivity control while reducing 20% IFBA use. This design exhibits lower assembly reactivity swing and minimal burnup penalty due to the self-shielding effect. Case 3 provides similar to 10% more initial (beginning-of-life) reactivity suppression with similar to 70% less reactivity swing compared to the IFBA-only design for UO2 fuel while achieving almost the same core lifetime. Finally, optimized Case 3 assemblies were loaded in 3D nodal diffusion and reactor model code. The results obtained from the 3D reactor model confirmed that the designed core with the proposed Case 3 BPs can achieve the target lifetime of 15 years while contributing to similar to 10% higher BOL reactivity suppression, similar to 70% lower reactivity swings, similar to 30% lower radial form factor and similar to 28% lower total peaking factor compared to the IFBA-only core.

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  • 44.
    Alam, Syed Bahauddin
    et al.
    Univ Cambridge, Dept Engn, Cambridge, England; Rhode Isl Nucl Sci Ctr, Narragansett, RI USA; French Alternat Energies & Atom Energy Commiss, St Paul Les Durance, France.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. French Alternat Energies & Atom Energy Commiss, St Paul Les Durance, France.
    Almutairi, B.
    Rhode Isl Nucl Sci Ctr, Narragansett, RI USA; Missouri S&T, Dept Nucl Engn, Rolla, MO USA.
    Bhowmik, P. K.
    Missouri S&T, Dept Nucl Engn, Rolla, MO USA.
    Goodwin, C.
    Rhode Isl Nucl Sci Ctr, Narragansett, RI USA.
    Parks, G. T.
    Univ Cambridge, Dept Engn, Cambridge, England.
    Small modular reactor core design for civil marine propulsion using micro-heterogeneous duplex fuel. Part I: Assembly-level analysis2019In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 346, p. 157-175Article in journal (Refereed)
    Abstract [en]

    In an effort to de-carbonise commercial freight shipping, there is growing interest in the possibility of using nuclear propulsion systems. In this reactor physics study, we seek to design a soluble-boron-free (SBF) and low-enriched uranium (LEU) (<20% U-235 enrichment) civil nuclear marine propulsion small modular reactor (SMR) core that provides at least 15 effective full-power-years (EFPY) life at 333 MWth using 18% U-235 enriched micro-heterogeneous ThO2-UO2 duplex fuel and 15% U-235 enriched homogeneously mixed all-UO2 fuel. We use WIMS to develop subassembly designs and PANTHER to examine whole-core arrangements.

    The assembly-level behaviours of candidate burnable poison (BP) materials and control rods are investigated. We examine gadolinia (Gd2O3), erbia (Er2O3) and ZrB2 integral fuel burnable absorber (IFBA) as BPs. We arrive at a design with the candidate fuels loaded into 13 x 13 assemblies using IFBA pins for reactivity control. Taking advantage of self-shielding effects, this design maintains low and stable assembly reactivity with relatively little burnup penalty. Thorium-based duplex fuel offers better performance than all-UO2 fuel with all BP options considered. Duplex fuel has similar to 20% lower reactivity swing and, in consequence, lower initial reactivity than all-UO2 fuel. The lower initial reactivity and smaller reactivity swing make the task of reactivity control through BP design easier in the thorium-rich duplex core. For control rod design, we examine boron carbide (B4C), hafnium, and Ag-In-Cd alloy. All the candidate materials exhibit greater rod worth for the duplex design. For both fuels, B4C has the highest rod worth. In particular, one of the major objectives of this study is to offer/explore a thorium-based candidate alternative fuel platform for the proposed marine core. It is proven by literature reviews that the ability of the duplex fuel was never explored in the context of a single-batch, LEU, SBF, long-life SMR core. In this regard, the motivation of this paper is to observe the neutronic performance of the proposed duplex fuel with respect to the UO2 fuel and 'open the option' of designing the functional cores with both the duplex and UO2 fuel cores.

  • 45.
    Alam, Syed Bahauddin
    et al.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Almutairi, Bader
    Missouri S&T, Dept Nucl Engn, Rolla, MO USA.
    Ridwan, Tuhfatur
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Goodwin, Cameron
    Rhode Isl Nucl Sci Ctr, 16 Reactor Rd, Narragansett, RI 02882 USA.
    Parks, Geoffrey T.
    Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England.
    Lattice benchmarking of deterministic, Monte Carlo and hybrid Monte Carlo reactor physics codes for the soluble-boron-free SMR cores2020In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 356, article id 110350Article in journal (Refereed)
    Abstract [en]

    Since the use of deterministic transport code WIMS can significantly reduce the computational time compared to the Monte Carlo (MC) code Serpent and hybrid MC code MONK, one of the major objectives of this study is to observe whether deterministic code WIMS can provide accuracy in reactor physics calculations while comparing Serpent and MONK. Therefore, numerical benchmark calculations for a soluble-boron-free (SBF) small modular reactor (SMR) assembly have been performed using the WIMS, Serpent and MONK. Although computationally different in nature, these codes can solve the neutronic transport equations and calculate the required neutronic parameters. A comparison in neutronic parameters between the three codes has been carried out using two types of candidate fuels: 15% U-235 enriched homogeneously mixed all-UO2 fuel and 18% U-235 enriched micro-heterogeneous ThO2-UO2 duplex fuel in a 2D fuel assembly model using a 13x13 arrangement. The eigenvalue/ reactivity (k(infinity)) and 2D assembly pin power distribution at different burnup states in the assembly depletion are compared using three candidate nuclear data files: ENDF/B-VII, JEF2.2 and JEF3.1. A good agreement in k(infinity) values was observed among the codes for both the candidate fuels. The differences in k(infinity) between the codes are similar to 200 pcm when cross-sections based on the same nuclear data file are used. A higher difference (up to similar to 450 pcm) in the k(infinity) values is observed among the codes using cross-sections based on different data files. Finally, it can be concluded from this study that the good agreement in the results between the codes found provides enhanced confidence that modeling of SBF, SMR propulsion core systems with micro-heterogeneous duplex fuel can be performed reliably using deterministic neutronics code WIMS, offering the advantage of less expensive computation than that of the MC Serpent and hybrid MC MONK codes.

  • 46.
    Alam, Syed Bahauddin
    et al.
    Univ Cambridge, Dept Engn, Cambridge, England; Rhode Isl Nucl Sci Ctr, Narragansett, RI USA; French Alternat Energies & Atom Energy Commiss, Saint Paul Lez Durance, France.
    Ridwan, T.
    Univ Cambridge, Dept Engn, Cambridge, England.
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. French Alternat Energies & Atom Energy Commiss, Saint Paul Lez Durance, France.
    Almutairi, B.
    Rhode Isl Nucl Sci Ctr, Narragansett, RI USA; Missouri S&T, Dept Nucl Engn, Rolla, MO USA.
    Goodwin, C.
    Rhode Isl Nucl Sci Ctr, Narragansett, RI USA.
    Parks, G. T.
    Univ Cambridge, Dept Engn, Cambridge, England.
    Small modular reactor core design for civil marine propulsion using micro-heterogeneous duplex fuel. Part II: whole-core analysis2019In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 346, p. 176-191Article in journal (Refereed)
    Abstract [en]

    Civil marine reactors face a unique set of design challenges. These include requirements for a small core size and long core lifetime, a 20% cap on fissile loading, and limitations on using soluble neutron absorbers. In this reactor physics study, we seek to design a core that meets these requirements over a 15 effective full-power-years (EFPY) life at 333 MWth using homogeneously mixed all-UO2 and micro-heterogeneous ThO2-UO2 duplex fuels. In a companion (Part I) paper, we found assembly designs using 15% and 18% U-235 for UO2 and duplex fuels, respectively, loaded into 13 x 13 pin arrays. High thickness (150 mu m) ZrB2 integral fuel burnable absorber (IFBA) pins and boron carbide (B4C) control rods are used for reactivity control. Taking advantage of self-shielding effects, these designs maintain low and stable assembly reactivity with little burnup penalty.

    In this paper (Part II), whole-core design analyses are performed for small modular reactor (SMR) to determine whether the core remains critical for at least 15 EFPY with a reactivity swing of less than 4000 pcm, subject to appropriate constraints. The main challenge is to keep the radial form factor below its limit (1.50). Burnable poison radial-zoning is examined in the quest for a suitable arrangement to control power peaking. Optimized assemblies are loaded into a 3D reactor model in PANTHER. The PANTHER results confirm that the fissile loadings of both fuels are well-designed for the target lifetime: at the end of the (similar to)15-year cycle, the cores are on the border of criticality. The duplex fuel core can achieve (similar to)4% longer core life, has a (similar to)3% lower initial reactivity and (similar to)30% lower reactivity swing over life than the final UO2 core design. The duplex core is therefore the more successful design, giving a core life of (similar to)16 years and a reactivity swing of less than 2500 pcm, while satisfying all the neutronic safety parameters. In particular, one of the major objectives of this study is to offer/explore a thorium-based candidate alternative fuel platform for the proposed marine core. It is proven by literature reviews that the ability of the duplex fuel was never explored in the context of a single-batch, LEU, SBF, long-life SMR core. In this regard, the motivation of this paper is to understand the underlying physics of the duplex fuel and 'open the option' of designing the functional cores with both the duplex and UO2 fuel cores.

  • 47.
    Alam, Syed Bahauddin
    et al.
    CEA Cadarache.
    Tao, Feng
    Kumar, Dinesh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. CEA Cadarache.
    Ridwan, T.
    Almutairi, B.
    Goodwin, C.
    Computational Modeling of Doppler Coefficient For 3D AGR Pin-Cell using the Coupling of Deterministic Method & Matlab2019Conference paper (Other academic)
  • 48.
    Alcayne, V.
    et al.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Cano-Ott, D.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Garcia, J.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Gonzalez-Romero, E.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Martinez, T.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Mendoza, E.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Sanchez, A.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Plaza, J.
    Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain..
    Balibrea-Correa, J.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Casanovas, A.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Univ Lodz, Lodz, Poland..
    Domingo-Pardo, C.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Univ Lodz, Lodz, Poland..
    Lerendegui-Marco, J.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Univ Lodz, Lodz, Poland..
    Aberle, O.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Altieri, S.
    European Org Nucl Res CERN, Geneva, Switzerland.;Ist Nazl Fis Nucl, Sez Pavia, Pavia, Italy..
    Amaducci, S.
    Univ Pavia, Dept Phys, Pavia, Italy..
    Es-Sghir, H. Amar
    INFN Lab Nazl Sud, Catania, Italy..
    Andrzejewski, J.
    Univ Granada, Granada, Spain..
    Babiano-Suarez, V.
    Univ Lodz, Lodz, Poland..
    Bacak, M.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Balibreas, J.
    Univ Lodz, Lodz, Poland..
    Bennett, S.
    Univ Manchester, Manchester, Lancs, England..
    Bernardes, A. P.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Berthoumieux, E.
    Univ Paris Saclay, CEA Irfu, F-91191 Gif Sur Yvette, France..
    Bosnar, D.
    Univ Zagreb, Dept Phys, Fac Sci, Zagreb, Croatia..
    Busso, M.
    Ist Nazl Fis Nucl, Sez Perugia, Perugia, Italy.;Univ Perugia, Dipartimento Fis & Geol, Perugia, Italy..
    Caamano, M.
    Univ Santiago Compostela, Santiago, Spain..
    Calvino, F.
    Univ Politecn Cataluna, Barcelona, Spain..
    Calviani, M.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Cano-Ottl, D.
    Castelluccio, D. M.
    Agenzia Nazl Nuove Tecnol ENEA, Portici, Italy.;Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy..
    Cerutti, F.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Cescutti, G.
    Ist Nazl Fis Nucl, Sez Trieste, Trieste, Italy.;Univ Trieste, Dept Phys, Trieste, Italy..
    Chasapoglou, S.
    Natl Tech Univ Athens, Athens, Greece..
    Chiaveri, E.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Univ Manchester, Manchester, Lancs, England..
    Colombetti, P.
    Ist Nazl Fis Nucl, Sez Torino, Turin, Italy.;Univ Torino, Dept Phys, Turin, Italy..
    Colonna, N.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy..
    Camprini, P. C. Console
    Agenzia Nazl Nuove Tecnol ENEA, Portici, Italy.;Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy..
    Cortes, G.
    Univ Politecn Cataluna, Barcelona, Spain..
    Cortes-Giraldo, M. A.
    Univ Seville, Seville, Spain..
    Cosentino, L.
    Univ Pavia, Dept Phys, Pavia, Italy..
    Cristallo, S.
    Ist Nazl Fis Nucl, Sez Perugia, Perugia, Italy.;Ist Nazl Astrofis, Osservatorio Astron Teramo, Teramo, Italy..
    Di Castro, M.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Diacono, D.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy..
    Diakaki, M.
    Natl Tech Univ Athens, Athens, Greece..
    Dietz, M.
    Phys Tech Bundesanstalt PTB, Bundesallee 100, D-38116 Braunschweig, Germany..
    Dressler, R.
    Paul Scherrer Inst PSI, Villigen, Switzerland..
    Dupont, E.
    Univ Paris Saclay, CEA Irfu, F-91191 Gif Sur Yvette, France..
    Duran, I.
    Univ Santiago Compostela, Santiago, Spain..
    Eleme, Z.
    Univ Ioannina, Ioannina, Greece..
    Fargier, S.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Fernandez-Dominguez, B.
    Univ Santiago Compostela, Santiago, Spain..
    Finocchiaro, P.
    Univ Pavia, Dept Phys, Pavia, Italy..
    Fiore, S.
    Agenzia Nazl Nuove Tecnol ENEA, Portici, Italy.;Ist Nazl Fis Nucl, Sez Roma1, Rome, Italy..
    Furman, V.
    Joint Inst Nucl Res JINR, Dubna, Russia..
    Garcia-Infantes, F.
    INFN Lab Nazl Sud, Catania, Italy..
    Gawlik-Ramiega, A.
    Univ Granada, Granada, Spain..
    Gervino, G.
    Ist Nazl Fis Nucl, Sez Torino, Turin, Italy.;Univ Torino, Dept Phys, Turin, Italy..
    Gilardoni, S.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Guerrero, C.
    Univ Seville, Seville, Spain..
    Gunsing, F.
    Univ Paris Saclay, CEA Irfu, F-91191 Gif Sur Yvette, France..
    Gustavino, C.
    Ist Nazl Fis Nucl, Sez Roma1, Rome, Italy..
    Heyse, J.
    European Commiss, Joint Res Ctr JRC, Geel, Belgium..
    Jenkins, D. G.
    Univ York, York, N Yorkshire, England..
    Jericha, E.
    TU Wien, Atominst, Stadionallee 2, A-1020 Vienna, Austria..
    Junghans, A.
    Helmholtz Zentrum Dresden Rossendorf, Dresden, Germany..
    Kadi, Y.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Katabuchi, T.
    Tokyo Inst Technol, Tokyo, Japan..
    Knapova, I.
    Charles Univ Prague, Prague, Czech Republic..
    Kokkoris, M.
    Natl Tech Univ Athens, Athens, Greece..
    Kopatch, Y.
    Joint Inst Nucl Res JINR, Dubna, Russia..
    Krticka, M.
    Charles Univ Prague, Prague, Czech Republic..
    Kurtulgil, D.
    Goethe Univ Frankfurt, Frankfurt, Germany..
    Ladarescu, I.
    Univ Lodz, Lodz, Poland..
    Lederer-Woods, C.
    Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland..
    Lerner, G.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Manna, A.
    Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy.;Univ Bologna, Dipartimento Fis & Astron, Bologna, Italy..
    Masi, A.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Massimi, C.
    Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy.;Univ Bologna, Dipartimento Fis & Astron, Bologna, Italy..
    Mastinu, P.
    INFN Lab Nazl Legnaro, Legnaro, Italy..
    Mastromarco, M.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy.;Univ Bari, Dipartimento Interateneo Fis, Bari, Italy..
    Matteucci, F.
    Ist Nazl Fis Nucl, Sez Trieste, Trieste, Italy.;Univ Trieste, Dept Phys, Trieste, Italy..
    Maugeri, E. A.
    Paul Scherrer Inst PSI, Villigen, Switzerland..
    Mazzone, A.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy.;CNR, Bari, Italy..
    Mengoni, A.
    Agenzia Nazl Nuove Tecnol ENEA, Portici, Italy.;Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy..
    Michalopoulou, V.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Natl Tech Univ Athens, Athens, Greece..
    Milazzo, P. M.
    Ist Nazl Fis Nucl, Sez Trieste, Trieste, Italy..
    Mucciola, R.
    Ist Nazl Fis Nucl, Sez Perugia, Perugia, Italy.;Univ Perugia, Dipartimento Fis & Geol, Perugia, Italy..
    Murtas, F.
    INFN Lab Nazl Frascati, Frascati, Italy..
    Musacchio-Gonzalez, E.
    INFN Lab Nazl Legnaro, Legnaro, Italy..
    Musumarra, A.
    Ist Nazl Fis Nucl, Catania, Italy.;Univ Catania, Dept Phys & Astron, Catania, Italy..
    Negret, A.
    Horia Hulubei Natl Inst Phys & Nucl Engn, Magurele, Romania..
    Oprea, A.
    Horia Hulubei Natl Inst Phys & Nucl Engn, Magurele, Romania..
    Perez-Maroto, P.
    Univ Seville, Seville, Spain..
    Patronis, N.
    Univ Ioannina, Ioannina, Greece..
    Pavon-Rodriguez, J. A.
    Pellegriti, M. G.
    Ist Nazl Fis Nucl, Catania, Italy..
    Perkowski, J.
    Univ Granada, Granada, Spain..
    Petrone, C.
    Horia Hulubei Natl Inst Phys & Nucl Engn, Magurele, Romania..
    Piersanti, L.
    Ist Nazl Fis Nucl, Sez Perugia, Perugia, Italy.;Ist Nazl Astrofis, Osservatorio Astron Teramo, Teramo, Italy..
    Pirovano, E.
    Phys Tech Bundesanstalt PTB, Bundesallee 100, D-38116 Braunschweig, Germany..
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Porras, I.
    INFN Lab Nazl Sud, Catania, Italy..
    Praena, J.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;INFN Lab Nazl Sud, Catania, Italy..
    Protti, N.
    European Org Nucl Res CERN, Geneva, Switzerland.;Ist Nazl Fis Nucl, Sez Pavia, Pavia, Italy..
    Quesada, J. M.
    Univ Seville, Seville, Spain..
    Rauscher, T.
    Univ Basel, Dept Phys, Basel, Switzerland..
    Reifarth, R.
    Goethe Univ Frankfurt, Frankfurt, Germany..
    Rochman, D.
    Paul Scherrer Inst PSI, Villigen, Switzerland..
    Romanets, Y.
    Inst Super Tecn, Lisbon, Portugal..
    Romano, F.
    Ist Nazl Fis Nucl, Catania, Italy..
    Rubbia, C.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Sabate-Gilarte, M.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Schillebeeckx, P.
    European Commiss, Joint Res Ctr JRC, Geel, Belgium..
    Schumann, D.
    Paul Scherrer Inst PSI, Villigen, Switzerland..
    Sekhar, A.
    Univ Manchester, Manchester, Lancs, England..
    Smith, A. G.
    Univ Manchester, Manchester, Lancs, England..
    Sosnin, N. V.
    Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland..
    Spelta, M.
    Ist Nazl Fis Nucl, Sez Bologna, Bologna, Italy.;Univ Bologna, Dipartimento Fis & Astron, Bologna, Italy..
    Stamati, M. E.
    Univ Ioannina, Ioannina, Greece..
    Tagliente, G.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy..
    Tarifeno-Saldivia, A.
    Univ Politecn Cataluna, Barcelona, Spain..
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Terranova, N.
    Agenzia Nazl Nuove Tecnol ENEA, Portici, Italy.;INFN Lab Nazl Frascati, Frascati, Italy..
    Torres-Sanchez, P.
    INFN Lab Nazl Sud, Catania, Italy..
    Urlass, S.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain.;Helmholtz Zentrum Dresden Rossendorf, Dresden, Germany..
    Valenta, S.
    Charles Univ Prague, Prague, Czech Republic..
    Variale, V.
    Ist Nazl Fis Nucl, Sez Bari, Bari, Italy..
    Vaz, P.
    Inst Super Tecn, Lisbon, Portugal..
    Vescovi, D.
    Goethe Univ Frankfurt, Frankfurt, Germany..
    Vlachoudis, V.
    Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain..
    Vlastou, R.
    Natl Tech Univ Athens, Athens, Greece..
    Wallner, A.
    Australian Natl Univ, Canberra, ACT, Australia..
    Woods, P. J.
    Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland..
    Wright, T.
    Univ Manchester, Manchester, Lancs, England..
    Zugec, P.
    Univ Zagreb, Dept Phys, Fac Sci, Zagreb, Croatia..
    A segmented total energy detector (sTED) for (n, gamma) cross section measurements at n_TOF EAR22023In: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022 / [ed] Mattoon, CM Vogt, R Escher, J Thompson, I, EDP Sciences, 2023, Vol. 284, article id 01043Conference paper (Refereed)
    Abstract [en]

    The neutron time-of-flight facility n_TOF is characterised by its high instantaneous neutron intensity, high resolution and broad neutron energy spectra, specially conceived for neutron-induced reaction cross section measurements. Two Time-Of-Flight (TOR) experimental areas are available at the facility: experimental area 1 (EAR1), located at the end of the 185 m horizontal flight path from the spallation target, and experimental area 2 (EAR2), placed at 20 m from the target in the vertical direction. The neutron fluence in EAR2 is similar to 300 times more intense than in EARL in the relevant time-of-flight window. EAR2 was designed to carry out challenging cross-section measurements with low mass samples (approximately 1 mg), reactions with small cross-sections or/and highly radioactive samples. The high instantaneous fluence of EAR2 results in high counting rates that challenge the existing capture systems. Therefore, the sTED detector has been designed to mitigate these effects. In 2021, a dedicated campaign was done validating the performance of the detector up to at least 300 keV neutron energy. After this campaign, the detector has been used to perform various capture cross section measurements at n_TOF EAR2.

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  • 49.
    Aldahan, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svensson Grape, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Beräkning av kostnader för lågaktiv kärnavfallshantering2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The surtax in Sweden, which exclusively applies for nuclear power plants, in conjunction with low electricity prices, has forced Swedish nuclear power plants to minimize their expenses.

    At Oskarshamn power plant, estimation of cost, associated with low-level nuclear waste management has been conducted several years ago, but with lacking knowledge about how the calculations were performed. Therefore, the purpose of this project was to establish an independent cost estimation for compactible and non-compactible, low level and medium level nuclear waste. Cost estimates for free released low-level nuclear waste was also performed.

    By analyzing average economic figures from year 2014-2015 and visits on-site, an excel-based calculation template was accomplished. During the on-site studies, several visits to the low-level nuclear waste management facilities at Oskarshamn power plant were made, in order to get an overview of how the handling process works.

    By following the staff around, it was possible to estimate some of the time durations for the different parts in the handling process for compactible lowlevel nuclear waste, that were used in the calculations.

    The price for compactible low-level nuclear waste was calculated to 6,72 - 6,97 kr/kg, depending on the activity level. The non-compactible low-level nuclear waste price was found to vary between 4 – 48 kr/kg.

    The large fluctuations are due to different activity levels and associated additional costs in handling, measuring, final deposition etc.

    For both compactible and non-compactible nuclear waste, the storage cost is a factor that dominates the total cost and that could be minimized. Based on the analysis presented in this work, the cost can be decreased by reducing the storage time and/or store the nuclear waste in a more space efficient way.

    The cost estimate for free released material is low (5,94 – 8,74 kr/kg), which concludes that Oskarshamn power plant may profit from free releasing as much material as possible, due to the fact that it is highly profitable to recycle metals.

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    fulltext
  • 50.
    Alfheim, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Definition and evaluation of a dynamic source term module for use within RASTEP: A feasibility study2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    RASTEP (RApid Source TErm Prediction) is a computerized tool for use in the fast diagnosis of accidents in nuclear power plants and analysis of the subsequent radiological source term. The tool is based on a Bayesian Belief Network that is used to determine the most likely plant state which in turn is associated with a pre-calculated source term from level 2 PSA. In its current design the source term predicting abilities of RASTEP are not flexible enough. Therefore, the purpose of this thesis is to identify and evaluate different approaches of enhancing the source term module of RASTEP and provide the foundation for future implementations. Literature studies along with interviews and analysis have been carried out in order to identify possible methods and also to rank them according to feasibility. 4 main methods have been identified of which 2 are considered the most feasible in the short term. The other 2 might prove useful when their maturity level is strengthened. It is concluded from the study that the identified methods can be used in order to enhance RASTEP.

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    fulltext
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