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  • 1.
    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.

  • 2.
    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.

  • 3.
    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.

  • 4.
    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.

  • 5. Gorelov, D.
    et al.
    Hakala, J.
    Jokinen, A.
    Kolhinen, V.
    Koponen, J.
    Moore, I.
    Penttila, H.
    Pohjalainen, I.
    Reponen, M.
    Rinta-Antila, S.
    Sonnenschein, V.
    Voss, A.
    Al-Adili, Ali
    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.
    Pomp, Stephan
    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.
    Simutkin, Vasily
    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.
    Aysto, J.
    Isomeric Yield Ratios of Fission Products Measured with the Jyfltrap2014In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 45, no 2, p. 211-216Article in journal (Refereed)
    Abstract [en]

    Experimental methods to determine isomeric yield ratios usually apply gamma-spectroscopic techniques. In such methods, ground and isomeric states are distinguished by their decays. In the present work, several isomeric yield ratios of fission products have been measured by utilizing capabilities of the double Penning-trap mass spectrometer JYFLTRAP, where isomeric and ground state were separated by their masses. To verify the new experimental technique, the results were compared to those from gamma-spectroscopy measurements.

  • 6. Gorelov, D.
    et al.
    Penttilä, H.
    Al-Adili, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eronen, T.
    Hakala, J.
    Jokinen, A.
    Kankainen, A.
    Kolhinen, V. S.
    Koponen, J.
    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.
    Moore, I. D.
    Pohjalainen, I.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakoupoulos, V
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Reinikainen, J.
    Rinta-Antila, S.
    Simutkin, V.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Voss, A.
    Äystö, J.
    Developments for neutron-induced fission at IGISOL-42016In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584Article in journal (Refereed)
    Abstract [en]

    Abstract At the IGISOL-4 facility, neutron-rich, medium mass nuclei have usually been produced via charged particle-induced fission of natural uranium and thorium. Neutron-induced fission is expected to have a higher production cross section of the most neutron-rich species. Development of a neutron source along with a new ion guide continues to be one of the major goals since the commissioning of IGISOL-4. Neutron intensities at different angles from a beryllium neutron source have been measured in an on-line experiment with a 30 MeV proton beam. Recently, the new ion guide coupled to the neutron source has been tested as well. Details of the neutron source and ion guide design together with preliminary results from the first neutron-induced fission experiment at IGISOL-4 are presented in this report.

  • 7. Gorelov, D.A.
    et al.
    Eronen, T.
    Hakala, J.
    Jokinen, A.
    Kankainen, A.
    Kolhinen, V.S.
    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.
    Moore, I.
    Penttilä, H.
    Pohjalainen, I.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Reponen, M.
    Rinta-Antila, S.
    Rissanen, J.
    Rubchenya, V.
    Saastamoinen, A.
    Simutkin, V.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sonnenschein, V.
    Äysto, J.
    Independent fission yield measurements with jyfltrap2014In: Минск: Изд. центр БГУArticle in journal (Other academic)
  • 8. Kolhinen, V. S.
    et al.
    Eronen, T.
    Gorelov, D.
    Hakala, J.
    Jokinen, A.
    Jokiranta, K.
    Kankainen, A.
    Koikkalainen, M.
    Koponen, J.
    Kulmala, H.
    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.
    Moore, I. D.
    Penttilä, H.
    Pikkarainen, T.
    Pohjlainen, I.
    Reponen, M.
    Rinta-Antila, S.
    Rissanen, J.
    Rodriguez Triguero, C.
    Rytkönen, K.
    Saastamoinen, A.
    Solders, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sonnenschein, V.
    Ąystö, J.
    Recommissioning of JYFLTRAP at the new IGISOL-4 facility2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 317, no Part B, p. 506-509Article in journal (Refereed)
    Abstract [en]

    The JYFLTRAP double Penning-trap system was moved to a new location along with the Ion Guide Isotope Separator On-line (IGISOL) facility at the Accelerator Laboratory of the University of Jyväskylä. The move made it possible to upgrade various parts of the facility. For example, separate beam lines for JYFLTRAP and the collinear laser spectroscopy station were constructed after the radio-frequency quadrupole cooler and buncher. In this contribution we give an overview of the new JYFLTRAP facility and results from the first stable ion-beam tests.

  • 9.
    Lantz, Mattias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Al-Adili, Ali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, D.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Jokinen, A.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Kolhinen, V. S.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moore, I.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Penttila, H.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Pomp, Stephan
    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.
    Rinta-Antila, S.
    Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Simutkin, Vasily
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Univ Jyvaskyla, Dept Phys, SF-40351 Jyvaskyla, Finland..
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fission yield measurements at IGISOL2016In: CNR*15 - 5th International Workshop On Compound-Nuclear Reactions And Related Topics / [ed] Kawano, T; Chiba, S; Paris, MW; Talou, P, 2016, article id 01008Conference paper (Refereed)
    Abstract [en]

    The fission product yields are an important characteristic of the fission process. In fundamental physics, knowledge of the yield distributions is needed to better understand the fission process. For nuclear energy applications good knowledge of neutron-induced fission-product yields is important for the safe and efficient operation of nuclear power plants. With the Ion Guide Isotope Separator On-Line (IGISOL) technique, products of nuclear reactions are stopped in a buffer gas and then extracted and separated by mass. Thanks to the high resolving power of the JYFLTRAP Penning trap, at University of Jyvaskyla, fission products can be isobarically separated, making it possible to measure relative independent fission yields. In some cases it is even possible to resolve isomeric states from the ground state, permitting measurements of isomeric yield ratios. So far the reactions U(p,f) and Th(p,f) have been studied using the IGISOL-JYFLTRAP facility. Recently, a neutron converter target has been developed utilizing the Be(p,xn) reaction. We here present the IGISOL-technique for fission yield measurements and some of the results from the measurements on proton induced fission. We also present the development of the neutron converter target, the characterization of the neutron field and the first tests with neutron-induced fission.

  • 10.
    Lantz, Mattias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, D
    Al-Adili, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jokinen, A
    Kolhinen, V
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rinta-Antila, S
    Penttilää, H
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakoupoulos, V
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simutkin, V
    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.
    Development of a neutron converter for studies of neutron-induced fission fragments at the IGISOL facility2014In: CERN Document ServerArticle in journal (Other academic)
  • 11.
    Lantz, Mattias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorelov, Dmitry
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Penttila, Heikki
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rados, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ryzhov, Igor
    Design of a neutron converter for fission studies at the IGISOL facility2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T150, p. 014020-Article in journal (Refereed)
    Abstract [en]

    The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyvaskyla, has been supplied with a new cyclotron which will provide proton or deuteron beams of the order of 100 mu A with up to 30 MeV energy. This makes it an ideal place for measurements of neutron-induced fission fragments from various actinides, in view of proposed future nuclear fuel cycles. In the present paper, some considerations for the design of a neutron converter, based on simulations with the Monte Carlo codes MCNPX and FLUKA, are described.

  • 12.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Characterization of a Neutron Source for Fission Yields Studies2014Licentiate thesis, comprehensive summary (Other academic)
    List of papers
    1. Characterization of a Be(p,xn) neutron source for fission yields measurements
    Open this publication in new window or tab >>Characterization of a Be(p,xn) neutron source for fission yields measurements
    Show others...
    2014 (English)In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. 416-418Article in journal (Refereed) Published
    Abstract [en]

    We report on measurements performed at The Svedberg Laboratory (TSL) to characterize a proton-neutron converter for independent fission yield studies at the IGISOL-JYFLTRAP facility (Jyväskylä, Finland). A 30-MeV proton beam impinged on a 5 mm water-cooled Beryllium target. Two independent experimental techniques have been used to measure the neutron spectrum: a Time-of-Flight (TOF) system to estimate the high-energy contribution, and a Bonner Sphere Spectrometer to provide precise results from thermal energies up to 20 MeV. An overlap between the energy regions covered by the two systems will permit a cross-check of the results from the different techniques. In this paper, the measurement and the analysis technique will be presented together with some preliminary results.

    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:uu:diva-233411 (URN)10.1016/j.nds.2014.08.117 (DOI)000347706200233 ()
    Conference
    Nuclear Data for Science and Technology
    Available from: 2014-10-03 Created: 2014-10-03 Last updated: 2017-12-05Bibliographically approved
    2. Measurement of the energy spectrum from the neutron source planned for IGISOL
    Open this publication in new window or tab >>Measurement of the energy spectrum from the neutron source planned for IGISOL
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    2014 (English)In: Proceedings of the ERINDA Workshop, CERN, Geneva, Switzerland, 1-3 October 2013, CERN-Proceedings-2014-002, 2014, p. 39-45Conference paper, Published paper (Other academic)
    Series
    Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214
    National Category
    Other Physics Topics
    Identifiers
    urn:nbn:se:uu:diva-233416 (URN)978-92-9083-403-8 (ISBN)
    Conference
    The ERINDA 2013 Worskhop, Cern, Geneva, Switzerland, Oct 1-3 2013
    Available from: 2014-10-03 Created: 2014-10-03 Last updated: 2017-05-05Bibliographically approved
  • 13.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    nIGISOL 2016: Measurement of n-induced fission yields of tin and antimony2017Report (Other academic)
    Abstract [en]

    The first run of neutron-induced fission yields measurement at IGISOL-4 was performed from Friday December 9th to Monday December 12th, 2016.

    After mass separation of the fission products with the dipole magnets, ions were implanted on a movable tape and identified using γ-spectroscopy. Measurements were carried out using a Canberra GC7020 70% coaxial p-type HPGe detector.

    In this report, some details of the detector calibration and of the analysis procedure will be described.

  • 14.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Studying neutron-induced fission at IGISOL-4: From neutron source to yield measurements and model comparisons2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fission yields represent the probability of producing a certain nuclide in a fission event, and are important observables for fission research. For applications, accurate knowledge of the yields is fundamental at all stages of the fuel cycle of nuclear reactors, e.g., for reactivity calculations, or to estimate (spent) fuel inventory. Fission yields also help in the basic understanding of the fission process, for nucleosynthesis models, and for radioactive ion beam production.

    This thesis was developed in the framework of the AlFONS project, the objective of which was to measure neutron-induced fission yields of relevance for partitioning and transmutation of spent fuel. The work is performed at the IGISOL-4 facility in JYFL (University of Jyväskylä).

    The first part of this thesis work is dedicated to the development and characterisation of a suitable 9Be(p(30MeV),nx) neutron source for IGISOL-4. The neutron energy spectrum and the neutron yield from a 5mm thick converter were studied with Monte Carlo simulations. Two characterisation campaigns that validated the MCNPX code were also performed. At the maximum current available from the cyclotron at JYFL, a total neutron yield between 2 and 5×1012 neutrons/(sr s) can be obtained. This satisfies the design goal for studies of fission yields.

    The neutron source was used in the measurement of fission yields from high-energy neutron-induced fission of natU at IGISOL-4, discussed in the second part of this thesis. The fission products were online-separated with a dipole magnet. The isobars, with masses in the range A = 128-133, were identified using γ-spectroscopy. Data for the relative yields of tin and antimony, as well as isomeric yield ratios for five nuclides will be reported. The yields show trends not observed in the ENDF/B-VII.1 evaluation, and only in part confirmed by the GEF model.

    The final part of this thesis concerns a study of the performance of different nuclear model codes, that aim at describing the states of the fission fragments right after scission. Reproduction of experimental data serves to benchmark the models and it indicates, to some extent, how reliably the results can be extrapolated to regions where no data exist.

    A methodology to compare and test these models has been developed, which was implemented in the DEℓFIN code. DEℓFIN takes the excited fission fragments, defined by the model under test, and de-excites them in a standardised way using the nuclear model code TALYS. Eliminating any variability in the way the final observables are extracted helps focusing on each model's assumptions. DEℓFIN was tested on five models, and interesting features in the prompt neutron multiplicity were found for some of them. This study will promote a better understanding of the ideas used in the development of fission models.

    List of papers
    1. A neutron source for IGISOL-JYFLTRAP: Design and characterisation
    Open this publication in new window or tab >>A neutron source for IGISOL-JYFLTRAP: Design and characterisation
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    2017 (English)In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 53, no 173Article in journal (Refereed) Published
    Abstract [en]

    A white neutron source based on the Be(p,nx) reaction for fission studies at the IGISOLJYFLTRAP facility has been designed and tested. 30 MeV protons impinge on a 5mm thick water-cooled beryllium disc. The source was designed to produce at least 1012 fast neutrons/s on a secondary fission target, in order to reach competitive production rates of fission products far from the valley of stability.

    The Monte Carlo codes MCNPX and FLUKA were used in the design phase to simulate the neutron energy spectra. Two experiments to characterise the neutron field were performed: the first was carried out at The Svedberg Laboratory in Uppsala (SE), using an Extended-Range Bonner Sphere Spectrometer and a liquid scintillator which used the time-of-flight (TOF) method to determine the energy of the neutrons; the second employed Thin-Film Breakdown Counters for the measurement of the TOF, and activation foils, at the IGISOL facility in Jyväskylä (FI). Design considerations and the results of the two characterisation measurements are presented, providing benchmarks for the simulations.

    National Category
    Subatomic Physics
    Identifiers
    urn:nbn:se:uu:diva-328569 (URN)10.1140/epja/i2017-12362-x (DOI)000408661200001 ()
    Funder
    Swedish Radiation Safety AuthoritySwedish Nuclear Fuel and Waste Management Company, SKB
    Available from: 2017-08-26 Created: 2017-08-26 Last updated: 2017-12-01Bibliographically approved
    2. A methodology for the intercomparison of nuclear fission codes using TALYS
    Open this publication in new window or tab >>A methodology for the intercomparison of nuclear fission codes using TALYS