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  • 1. Baron-Wiechec, A.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, F.
    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, N.
    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, C.
    Hjalmarsson, Anders
    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, Physics, Department of Physics and Astronomy, The Svedberg Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. 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, M.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Thermal desorption spectrometry of beryllium plasma facing tiles exposed in the JET tokamak2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 133, p. 135-141Article in journal (Refereed)
    Abstract [en]

    The phenomena of retention and de-trapping of deuterium (D) and tritium (T) in plasma facing components (PFC) and supporting structures must be understood in order to limit or control total T inventory in larger future fusion devices such as ITER, DEMO and commercial machines. The goal of this paper is to present details of the thermal desorption spectrometry (TDS) system applied in total fuel retention assessment of PFC at the Joint European Torus (JET). Examples of TDS results from beryllium (Be) wall tile samples exposed to JET plasma in PFC configuration mirroring the planned ITER PFC is shown for the first time. The method for quantifying D by comparison of results from a sample of known D content was confirmed acceptable. The D inventory calculations obtained from Ion Beam Analysis (IBA) and TDS agree well within an error associated with the extrapolation from very few data points to a large surface area.

  • 2. Batistoni, P.
    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.
    Technical preparations for the in-vessel 14 MeV neutron calibration at JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 117, p. 107-114Article in journal (Refereed)
    Abstract [en]

    The power output of fusion devices is measured from their neutron yields which relate directly to the fusion yield. In this paper we describe the devices and methods that have been prepared to perform a new in situ 14 MeV neutron calibration at JET in view of the new DT campaign planned at JET in the next years. The target accuracy of this calibration is 10% as required for ITER, where a precise neutron yield measurement is important, e.g., for tritium accountancy. In this paper, the constraints and early decisions which defined the main calibration approach are discussed, e.g., the choice of 14 MeV neutron source and the deployment method. The physics preparations, source issues, safety and engineering aspects required to calibrate directly the JET neutron detectors are also discussed. The existing JET remote-handling system will be used to deploy the neutron source inside the JET vessel. For this purpose, compatible tooling and systems necessary to ensure safe and efficient deployment have been developed. The scientific programme of the preparatory phase is devoted to fully characterizing the selected 14 MeV neutron generator to be used as the calibrating source, obtain a better understanding of the limitations of the calibration, optimise the measurements and other provisions, and to provide corrections for perturbing factors (e.g., anisotropy of the neutron generator, neutron energy spectrum dependence on emission angle). Much of this work has been based on an extensive programme of Monte-Carlo calculations which provide support and guidance in developing the calibration strategy. i3/4 (C) 2017 EURATOM. 

  • 3.
    Batistoni, P.
    et al.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Campling, D.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Croft, D.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Giegerich, T.
    Karlsruhe Inst Technol, POB 3640, D-76021 Karlsruhe, Germany..
    Huddleston, T.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Lefebvre, X.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Lengar, I.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia..
    Lilley, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Peacock, A.
    Culham Sci Ctr, JET Exploitat Unit, Abingdon OX14 3DB, Oxon, England..
    Pillon, M.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Popovichev, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Reynolds, S.
    CCFE, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Vila, R.
    CIEMAT, Lab Nacl Fus, Madrid, Spain..
    Villari, R.
    ENEA, Dipartimento Fus & Sicurezza Nucl, Via E Fermi 45, I-00044 Frascati, Roma, Italy..
    Bekris, N.
    EUROfus Consortium, Culham Sci Ctr, ITER Phys Dept, Abingdon OX14 3DB, Oxon, England..
    Technological exploitation of Deuterium-Tritium operations at JET in support of ITER design, operation and safety2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 278-285Article in journal (Refereed)
    Abstract [en]

    Within the framework of the EUROfusion programme, a work-package of technology projects (WPJET3) is being carried out in conjunction with the planned Deuterium-Tritium experiment on JET (DTE2) with the objective of maximising the scientific and technological return of DT operations at JET in support of ITER. This paper presents the progress since the start of the project in 2014 in the preparatory experiments, analyses and studies in the areas of neutronics, neutron induced activation and damage in ITER materials, nuclear safety, tritium retention, permeation and outgassing, and waste production in preparation of DTE2.

  • 4.
    Biel, W.
    et al.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany;Univ Ghent, Dept Appl Phys, Ghent, Belgium.
    Albanese, R.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy.
    Ambrosino, R.
    Univ Napoli Parthenope, Consorzio CREATE, Naples, Italy.
    Ariola, M.
    Univ Napoli Parthenope, Consorzio CREATE, Naples, Italy.
    Berkel, M. , V
    Bolshakova, I
    Magnet Sensor Lab, Lvov, Ukraine.
    Brunner, K. J.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Cavazzana, R.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    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.
    Dinklage, A.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Duran, I
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Dux, R.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Eade, T.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.
    Entler, S.
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fable, E.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Farina, D.
    CNR, IFP, Milan, Italy.
    Figini, L.
    CNR, IFP, Milan, Italy.
    Finotti, C.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Franke, Th
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Giacomelli, L.
    CNR, IFP, Milan, Italy.
    Giannone, L.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Gonzalez, W.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hron, M.
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic.
    Janky, F.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Kallenbach, A.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Kogoj, J.
    Cosylab, Ljubljana, Slovenia.
    Koenig, R.
    Max Planck Inst Plasma Phys, Greifswald, Germany.
    Kudlacek, O.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Luis, R.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Malaquias, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Marchuk, O.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Marchiori, G.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Mattei, M.
    Univ Campania Luigi Vanvitelli, Consorzio CREATE, Caserta, Italy.
    Maviglia, F.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    De Masi, G.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Mazon, D.
    CEA, IRFM, F-13108 St Paul Les Durance, France.
    Meister, H.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Meyer, K.
    Cosylab, Ljubljana, Slovenia.
    Micheletti, D.
    CNR, IFP, Milan, Italy.
    Nowak, S.
    CNR, IFP, Milan, Italy.
    Piron, Ch
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy.
    Pironti, A.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy.
    Rispoli, N.
    CNR, IFP, Milan, Italy.
    Rohde, V
    Max Planck Inst Plasma Phys, Garching, Germany.
    Sergienko, G.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    El Shawish, S.
    Jozef Stefan Inst, Ljubljana, Slovenia.
    Siccinio, M.
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Silva, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    da Silva, F.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal.
    Sozzi, C.
    CNR, IFP, Milan, Italy.
    Tardocchi, M.
    CNR, IFP, Milan, Italy.
    Tokar, M.
    Forschungszentrum Julich, Inst Energie & Klimaforschurg, Julich, Germany.
    Treutterer, W.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Zohm, H.
    Max Planck Inst Plasma Phys, Garching, Germany.
    Diagnostics for plasma control -: From ITER to DEMO2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, no A, p. 465-472Article in journal (Refereed)
    Abstract [en]

    The plasma diagnostic and control (D&C) system for a future tokamak demonstration fusion reactor (DEMO) will have to provide reliable operation near technical and physics limits, while its front-end components will be subject to strong adverse effects within the nuclear and high temperature plasma environment. The ongoing developments for the ITER D&C system represent an important starting point for progressing towards DEMO. Requirements for detailed exploration of physics are however pushing the ITER diagnostic design towards using sophisticated methods and aiming for large spatial coverage and high signal intensities, so that many front-end components have to be mounted in forward positions. In many cases this results in a rapid aging of diagnostic components, so that additional measures like protection shutters, plasma based mirror cleaning or modular approaches for frequent maintenance and exchange are being developed. Under the even stronger fluences of plasma particles, neutron/gamma and radiation loads on DEMO, durable and reliable signals for plasma control can only be obtained by selecting diagnostic methods with regard to their robustness, and retracting vulnerable front-end components into protected locations. Based on this approach, an initial DEMO D&C concept is presented, which covers all major control issues by signals to be derived from at least two different diagnostic methods (risk mitigation).

    Download full text (pdf)
    FULLTEXT01
  • 5.
    Biel, W.
    et al.
    Forschungszentrum Julich, Inst Energie & Klimaforsch, Julich, Germany.;Univ Ghent, Dept Appl Phys, Ghent, Belgium..
    Ariola, M.
    Univ Napoli Parthenope, Consorzio Create, Naples, Italy..
    Bolshakova, I
    Magnet Sensor Lab, Lvov, Ukraine..
    Brunner, K. J.
    Max Planck Inst Plasma Phys, Greifswald, Germany..
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Duran, I
    Czech Acad Sci, Inst Plasma Phys, Prague, Czech Republic..
    Franke, Th
    Max Planck Inst Plasma Phys, Garching, Germany.;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany..
    Giacomelli, L.
    Ist Sci & Tecnol Plasmi, ISTP CNR, Milan, Italy..
    Giannone, L.
    Max Planck Inst Plasma Phys, Garching, Germany..
    Janky, F.
    Max Planck Inst Plasma Phys, Garching, Germany..
    Krimmer, A.
    Forschungszentrum Julich, Inst Energie & Klimaforsch, Julich, Germany..
    Luis, R.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal..
    Malaquias, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal..
    Marchiori, G.
    Univ Padua, Ist Nazl Fis Nucl, ENEA, Consorzio RFX,CNR, Padua, Italy..
    Marchuk, O.
    Forschungszentrum Julich, Inst Energie & Klimaforsch, Julich, Germany..
    Mazon, D.
    IRFM, CEA, F-13108 St Paul Les Durance, France..
    Pironti, A.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy..
    Quercia, A.
    Univ Napoli Federico II, Consorzio CREATE, Naples, Italy..
    Rispoli, N.
    Ist Sci & Tecnol Plasmi, ISTP CNR, Milan, Italy..
    El Shawish, S.
    Jozef Stefan Inst, Ljubljana, Slovenia..
    Siccinio, M.
    Max Planck Inst Plasma Phys, Garching, Germany.;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany..
    Silva, A.
    Univ Lisbon, Inst Plasmas & Fusao Nucl, IST, Lisbon, Portugal..
    Sozzi, C.
    Ist Sci & Tecnol Plasmi, ISTP CNR, Milan, Italy..
    Tartaglione, G.
    Univ Napoli Parthenope, Consorzio Create, Naples, Italy..
    Todd, T.
    UKAEA, Abingdon, Oxon, England..
    Treutterer, W.
    Max Planck Inst Plasma Phys, Garching, Germany..
    Zohm, H.
    Max Planck Inst Plasma Phys, Garching, Germany..
    Development of a concept and basis for the DEMO diagnostic and control system2022In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 179, article id 113122Article in journal (Refereed)
    Abstract [en]

    An initial concept for the plasma diagnostic and control (D&C) system has been developed as part of European studies towards the development of a demonstration tokamak fusion reactor (DEMO). The main objective is to develop a feasible, integrated concept design of the DEMO D&C system that can provide reliable plasma control and high performance (electricity output) over extended periods of operation. While the fusion power is maximized when operating near to the operational limits of the tokamak, the reliability of operation typically improves when choosing parameters significantly distant from these limits. In addition to these conflicting requirements, the D&C development has to cope with strong adverse effects acting on all in vessel components on DEMO (harsh neutron environment, particle fluxes, temperatures, electromagnetic forces, etc.). Moreover, space allocation and plasma access are constrained by the needs for first wall integrity and optimization of tritium breeding. Taking into account these boundary conditions, the main DEMO plasma control issues have been formulated, and a list of diagnostic systems and channels needed for plasma control has been developed, which were selected for their robustness and the required coverage of control issues. For a validation and refinement of this concept, simulation tools are being refined and applied for equilibrium, kinetic and mode control studies.

    Download full text (pdf)
    fulltext
  • 6.
    Binda, Federico
    et al.
    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.
    Conroy, Sean
    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.
    Calculation of the profile-dependent neutron backscatter matrix for the JET neutron camera system2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 865-868Article in journal (Refereed)
    Abstract [en]

    We investigated the dependence of the backscatter component of the neutron spectrum on the emissivity profile. We did so for the JET neutron camera system, by calculating a profile-dependent backscatter matrix for each of the 19 camera channels using a MCNP model of the JET tokamak. We found that, when using a low minimum energy for the summation of the counts in the neutron pulse height spectrum, the backscatter contribution can depend significantly on the emissivity profile. The maximum variation in the backscatter level was 24% (8.0% when compared to the total emission). This effect needs to be considered when a correction for the backscatter contribution is applied to the measured profile.

    Download full text (pdf)
    fulltext
  • 7. Boltruczyk, G.
    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.
    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.
    Zoletnik, S.
    Development of MPPC-based detectors for high count rate DT campaigns at JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 940-944Article in journal (Refereed)
    Abstract [en]

    The products of fusion reactions at JET are measured using different diagnostic techniques. One of the methods is based on measurements of gamma-rays, originating from reactions between fast ions and plasma impurities. During the forthcoming deuterium-tritium (DT) campaign a particular attention will be paid to 4.44 MeV gamma-rays emitted in the Be-9(alpha,n gamma)C-12 reaction. Gamma-ray detectors foreseen for measurements in DT campaigns have to be able to register spectra at high count rates, up to approximately 500 kHz. For the Gamma-ray Camera at JET a new setup will be based on scintillators with a short decay time, e.g., CeBr3, and a multi-pixel photon counter (MPPC). We present two methods of output signal shortening in modules based on MPPC. A short detector output signal is necessary in order to minimize the number of pile up events at high count rates. One method uses a passive RC circuit with a pole zero cancellation, whereas an active transimpedance amplifier is used in the other one. Due to the strong dependence of MPPC properties on temperature variation, a special device MTCD@NCBJ was designed and produced to stabilize the gain in MPPC-based scintillation detectors. We show that this device guarantees stable working conditions.

  • 8. Boyer, Helen
    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.
    JET Tokamak, preparation of a safety case for tritium operations2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 1308-1312Article in journal (Refereed)
    Abstract [en]

    A new Safety Case is required to permit tritium operations on JET during the forthcoming DTE2 campaign. The outputs, benefits and lessons learned associated with the production of this Safety Case are presented. The changes that have occurred to the Safety Case methodology since the last JET tritium Safety Case are reviewed. Consideration is given to the effects of modifications, particularly ITER related changes, made to the JET and the impact these have on the hazard assessments as well as normal operations. Several specialized assessments, including recent MELCOR modelling, have been undertaken to support the production of this Safety Case and the impact of these assessments is outlined. Discussion of the preliminary actions being taken to progress implementation of this Safety Case is provided, highlighting new methods to improve the dissemination of the key Safety Case results to the plant operators. Finally, the work required to complete this Safety Case, before the next tritium campaign, is summarized. (C) 2016 EURATOM. Published by Elsevier B.V. All rights reserved.

  • 9.
    Calabro, G.
    et al.
    Department of Economics, Engineering, Society and Business Organization (DEIm), University of Tuscia, Largo dell’Università snc, Viterbo, Italy.
    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.
    Natl Ctr Nucl Res, Otwock, Poland.
    Divertor currents optimization procedure for JET-ILW high flux expansion experiments2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 129, p. 115-119Article in journal (Refereed)
    Abstract [en]

    This paper deals with a divertor coil currents optimized procedure to design High Flux Expansion (HFE) configurations in the JET tokamak aimed to study the effects of flux expansion variation on the radiation fraction and radiated power re-distribution. A number of benefits of HFE configuration have been experimentally demonstrated on TCV, EAST, NSTX and DIII-D tokamaks and are under investigation for next generation devices, as DEMO and DTT. The procedure proposed here exploits the linearized relation between the plasma-wall gaps and the Poloidal Field (PF) coil currents. Once the linearized model is provided by means of CREATE-NL code, the divertor coils currents are calculated using a constrained quadratic programming optimization procedure, in order to achieve HFE configuration. Flux expanded configurations have been experimentally realized both in ohmic and heated plasma with and without nitrogen seeding. Preliminary results on the effects of the flux expansion variation on total power radiation increase will be also briefly discussed.

  • 10.
    Cecconello, Marco
    et al.
    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.
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sperduti, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Casiraghi, Irene
    Mantica, Paola
    Vincenzi, Pietro
    Bolzonella, Tommaso
    Agostinetti, Piero
    Villari, Rosaria
    Conceptual design of a collimated neutron flux monitor and spectrometer for DTT2021In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 167, article id 112382Article in journal (Refereed)
    Abstract [en]

    A conceptual design and performance studies for a collimated neutron flux monitor and neutron spectrometer for the Divertor Tokamak Test (DTT) facility are presented. This study is based on the single-null divertor configuration and for “Half Power” and “Full power” scenarios with 15 MW of negative-ion NBI, 29 MW of ECH and 3 MW of ICRF heating with a maximum neutron yield of 1.5 × 1017 s−1. Fast ion distributions (both from auxiliary heating systems and fusion born) have been simulated in TRANSP/NUBEAM and the corresponding neutron energy spectra have been calculated using DRESS. Synthetic diagnostics have been implemented to determine the neutron fluxes and spectra at the detector location. Neutron emissivity profiles, plasma position, core ion temperature and the ratio of thermal and non-thermal D ion populations can be obtained with good accuracy and time resolution.

  • 11.
    Cecconello, Marco
    et al.
    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.
    Marocco, D.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Moro, F.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Esposito, B.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Neural network implementation for ITER neutron emissivity profile recognition2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 637-640Article in journal (Refereed)
    Abstract [en]

    The ITER Radial Neutron Camera (RNC) is a neutron diagnostic intended for the measurement of the neutron emissivity radial profile and the estimate of the total fusion power. This paper presents a proof of-principle method based on neural networks to estimate the neutron emissivity profile in different ITER scenarios and for different RNC architectures. The design, optimization and training of the implemented neural network is presented together with a decision algorithm to select, among the multiple trained neural networks, which one provides the inverted neutron emissivity profile closest to the input one. Examples are given for a selection of ITER scenarios and RNC architectures. The results from this study indicate that neural networks for the neutron emissivity recognition in ITER can achieve an accuracy and precision within the spatial and temporal requirements set by ITER for such a diagnostic.

  • 12.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Miklaszewski, R.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Marocco, D.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moro, F.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Esposito, B.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Podda, S.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy.
    Bienkowska, B.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Szydlowski, A.
    Inst Plasma Phys & Laser Microfus, Hery St 23, PL-01497 Warsaw, Poland.
    Strategy and guidelines for the calibration of the ITER Radial Neutron Camera2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, p. 2049-2052Article in journal (Refereed)
    Abstract [en]

    A calibration procedure is proposed for ITER Radial Neutron Camera that relies on embedded sources, reference ITER pulses and cross-calibration with ITER fission chambers and activation system coupled to Monte Carlo simulations of radiation transport. The proposed procedure would allow to measure the neutron emissivity profile and of the fusion power with 10 % accuracy and precision, a time resolution of 10 ms and a spatial resolution of a/10 for ITER entire life-time.

  • 13. Chiariello, Andrea Gaetano
    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.
    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.
    A 3D electromagnetic model of the iron core in JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 527-531Article in journal (Refereed)
    Abstract [en]

    The Magnet and Power Supplies system in JET includes a ferromagnetic core able to increase the transformer effect by improving the magnetic coupling with the plasma. The iron configuration is based on an inner cylindrical core and eight returning limbs; the ferromagnetic circuit is designed in such a way that the inner column saturates during standard operations [1]. The modelling of the magnetic circuit is a critical issue because of its impact on several applications, including equilibrium and reconstruction analysis required for control applications. The most used model in present applications is based on Equivalent Currents (ECs) placed on the iron boundary together with additional specific constraints, in a 2D axisymmetric frame. The (circular) ECs are chosen, by using the available magnetic measurements, to best represent the magnetic polarization effect [1]. Due to the axisymmetric assumption such approach is not well suited to deal with significant 3D effects, e.g. arising in operations with Error Field Correction Coils (EFCC). In this paper a new methodology is proposed, based on a set of 3D-shaped ECs and able to better model the actual 3D magnetization giving rise to a linear system to be solved. According to a well assessed approach [2], the 3D shape of ECs is represented by a set of elementary sources. The methodology has been successfully validated in a number of JET dry-run experiments where 3D effects are generated by EFCC currents. The new procedure has been designed to be easily coupled with equilibrium or reconstruction codes such as EFIT/V3FIT. The proposed model resulted to be very effective in representing 3D iron magnetization, especially if compared with typical 2D models. 

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  • 14. Coad, J. P.
    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.
    Material migration and fuel retention studies during the JET carbon divertor campaigns2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 138, p. 78-108Article in journal (Refereed)
    Abstract [en]

    The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994-5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favouring the inner divertor region result from drift in the scrape-off layer. A new monolithic divertor structure was installed in 1996 which produced heavy deposition at shadowed areas in the inner divertor corner, which is where the majority of the tritium was trapped by co-deposition during the deuterium-tritium experiment in 1997. Different divertor geometries have been tested since such as the Gas-Box and High-Delta divertors; a principle objective has been to predict plasma behaviour, transport and tritium retention in ITER. Transport modelling experiments were carried out at the end of four campaigns by puffing C-13-labelled methane, and a range of diagnostics such as quartz-microbalance and rotating collectors have been installed to add time resolution to the post-mortem analyses. The study of material migration after D-D and D-T campaigns clearly revealed important consequences of fuel retention in the presence of carbon walls. They gave a strong impulse to make a fundamental change of wall materials. In 2010 the carbon divertor and wall tiles were removed and replaced with tiles with Be or W surfaces for the ITER-Like Wall Project.

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  • 15. Coiling, Bethany
    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.
    Testing of tritium breeder blanket activation foil spectrometer during JET operations2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 258-264Article in journal (Refereed)
    Abstract [en]

    Accurate measurement of the nuclear environment within a test tritium breeding-blanket module of a fusion reactor is crucial to determine tritium production rates which are relevant to self-sufficiency of tritium fuel supply, tritium accountancy and also to the evaluation of localised power levels produced in blankets. This requires evaluation of the time-dependent spectral neutron flux within the test tritium breeding-blanket module under harsh radiation and temperature environments. The application of an activation foil-based spectrometer system to determine neutron flux density using a pneumatic transfer system in ITER has been studied, deployed and tested on the Joint European Torus (JET) machine in a recent deuterium - deuterium campaign for a selection of high purity activation foils. Deployment of the spectrometer system has provided important functional and practical testing of the detector measurement system, associated hardware and post processing techniques for the analysis of large data sets produced through the use of list mode data collection. The testing is invaluable for the optimisation of systems for future planned testing in tritium - tritium and deuterium - tritium conditions. Analysis of the time and energy spectra collected to date and the status of the development of methods for post processing are presented in this paper.

  • 16.
    Cruz, N.
    et al.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Pereira, R. C.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Santos, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Fernandes, A.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Sousa, J.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Marocco, D.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Riva, M.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Centioli, C.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Correia, C. M. B.
    Univ Coimbra, Dept Fis, LIBPhys UC, P-3004516 Coimbra, Portugal..
    Goncalves, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Esposito, B.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Real-time software tools for the performance analysis of the ITER Radial Neutron Camera2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1001-1005Article in journal (Refereed)
    Abstract [en]

    The Radial Neutron Camera (RNC) diagnostic is a neutron detection system with multiple collimators aiming at characterizing the neutron emission that will be produced by the ITER tokamak. The RNC plays a primary role for basic and advanced plasma control measurements and acts as backup for system machine protection measurements. During the RNC system level design phase the following real-time data processing algorithms were developed to assess RNC data throughput needs and measurement performances: (i) real-time data compression block (ii) real-time calculation of the neutron emissivity radial profile, based on Tikhonov regularization, starting from the line-integrated measurements, the line-of-sight geometry and using the magnetic flux information [1] (iii) real-time calculation of the neutron emissivity profile using a priori trained neural networks, the line-integrated measurements and the magnetic flux information (the best output from different neural networks being evaluated by a figure of merit that maps the neutron emissivity profile to the original line-integrated measurements) [21]. This paper presents results for the processing times of the various algorithms and their minimum control cycle for different conditions, such as number of lines of sight, number of magnetic flux surfaces and measurement error on the line integrated RNC measurements.

  • 17. Cufar, Aljaz
    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.
    Modelling of the neutron production in a mixed beam DT neutron generator2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1089-1093Article in journal (Refereed)
    Abstract [en]

    Compact DT neutron generators based on accelerators are often built on the principle of a mixed beam operation, meaning that deuterium (D) and tritium (T) are both present in the ion beam and in the target. Moreover, the beam consists of a mixture of ions and ionized molecules (D, T ions, and ionized D-D, T-T and D-T molecules) so the relevant source components come from T(d, n), D(t, n), D(d, n) and T(t, 2n) reactions at different ion energies. The method for assessing the relative amplitudes of different source components (DD, DT, TT) is presented. The assessment relies on the measurement of the neutron spectrum of different DT components (T(d, n) and D(t, n) at different energies) using a high resolution neutron spectrometer, e.g. a diamond detector, fusion reaction cross-sections, and simulations of neutron generation in the target. Through this process a complete description of the neutron source properties of the mixed beam neutron generator can be made and a neutron source description card, in a format suitable for Monte Carlo code MCNP, produced.

  • 18.
    Cufar, Aljaz
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Kodeli, Ivan
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Milocco, Alberto
    Culham Sci Ctr, Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Sauvan, Patrick
    UNED, ETS Ingn Ind, Dept Ingn Energet, C Juan del Rosal 12, Madrid 28040, Spain..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Comparison of DT neutron production codes MCUNED, ENEA-JSI source subroutine and DDT2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 164-168Article in journal (Refereed)
    Abstract [en]

    As the DT fusion reaction produces neutrons with energies significantly higher than in fission reactors, special fusion-relevant benchmark experiments are often performed using DT neutron generators. However, commonly used Monte Carlo particle transport codes such as MCNP or TRIPOLI cannot be directly used to analyze these experiments since they do not have the capabilities to model the production of DT neutrons. Three of the available approaches to model the DT neutron generator source are the MCUNED code, the ENEA-JSI DT source subroutine and the DDT code. The MCUNED code is an extension of the well-established and validated MCNPX Monte Carlo code. The ENEA-JSI source subroutine was originally prepared for the modelling of the FNG experiments using different versions of the MCNP code (-4, -5, -X) and was later extended to allow the modelling of both DT and DD neutron sources. The DDT code prepares the DT source definition file (SDEF card in MCNP) which can then be used in different versions of the MCNP code. In the paper the methods for the simulation of the DT neutron production used in the codes are briefly described and compared for the case of a simple accelerator-based DT neutron source.

  • 19. Curuia, Marian
    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.
    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.
    Upgrade of the tangential gamma-ray spectrometer beam-line for JET DT experiments2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 749-753Article in journal (Refereed)
    Abstract [en]

    The JET tangential gamma-ray spectrometer is undergoing an extensive upgrade in order to make it compatible with the forthcoming deuterium-tritium (DT) experiments. The paper presents the results of the design for the main components for the upgrade of the spectrometer beam-line: tandem collimators, gamma-ray shields, and neutron attenuators. The existing tandem collimators will be upgraded by installing two additional collimator modules. Two gamma-ray shields will define the gamma-ray field of-view at the detector end of the spectrometer line-of-sight. A set of three lithium hydride neutron attenuators will be used to control the level of the fast neutron flux on the gamma-ray detector. The design of the upgraded spectrometer beam-line has been supported by extensive radiation (neutron and photon) transport calculations using both large volume and point radiation sources.

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    FULLTEXT01
  • 20.
    Dittrich, Laura
    et al.
    KTH Royal Inst Technol, Fus Plasma Phys, S-10044 Stockholm, Sweden..
    Petersson, Per
    KTH Royal Inst Technol, Fus Plasma Phys, S-10044 Stockholm, Sweden..
    Moon, Sunwoo
    KTH Royal Inst Technol, Fus Plasma Phys, S-10044 Stockholm, Sweden..
    Rubel, Marek
    KTH Royal Inst Technol, Fus Plasma Phys, S-10044 Stockholm, Sweden..
    Tran, Tuan Thien
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Widdowson, Anna
    Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Contribuors, J E T
    Retention of noble and rare isotope gases in plasma-facing components-Experience from the JET tokamak with the ITER-like wall2023In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 192, article id 113620Article in journal (Refereed)
    Abstract [en]

    Plasma edge cooling, ion cyclotron wall conditioning and disruption mitigation techniques involve massive gas injection (by puffs or pellets) to the torus. A certain fraction remains in plasma-facing components (PFC) due to co-deposition and implantation. An uncontrolled release/desorption of such retained species affects the stability of plasma operation. The aim of this work was to determine the lateral and depth distribution of noble (3He, 4He, Ne, Ar), seeded (N2, Ne, Ar) and tracer gases (15N, 18O) in PFC retrieved from the JET tokamak with the ITER-Like Wall (JET-ILW) after three experimental campaigns (ILW-1, ILW-2, ILW-3). Results regarding the retention of those gases are shown as well as a comparison to the deuterium retention in the studied areas. Heavy ion elastic recoil detection analysis was used, being the only technique capable of detection and quantitative assessment of all elements, especially low-Z isotopes. Helium was found on the divertor Tile 5, locally up to 44.1015 3He cm-2 and 12.1015 4He cm-2, and on the limiters as well. Neon was found in two positions on the limiters, with up to 10.1015 Ne cm-2 and the 15N tracer on Be limiters exposed to ILW-3. A correlation of N retention with the N seeding rates for each campaign has also been found.

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    fulltext
  • 21.
    Drenik, A.
    et al.
    Max Planck Inst Plasma Phys, Garching, Germany; Jozef Stefan Inst, Ljubljana, Slovenia.
    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.
    Natl Ctr Nucl Res NCBJ, Otwock, Poland.
    Analysis of the outer divertor hot spot activity in the protection video camera recordings at JET2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 139, p. 115-123Article in journal (Refereed)
    Abstract [en]

    Hot spots on the divertor tiles at JET result in overestimation of the tile surface temperature which causes unnecessary termination of pulses. However, the appearance of hot spots can also indicate the condition of the divertor tile surfaces. To analyse the behaviour of the hot spots in the outer divertor tiles of JET, a simple image processing algorithm is developed. The algorithm isolates areas of bright pixels in the camera image and compares them to previously identified hot spots. The activity of the hot spots is then linked to values of other signals and parameters in the same time intervals. The operation of the detection algorithm was studied in a limited pulse range with high hot spot activity on the divertor tiles 5, 6 and 7. This allowed us to optimise the values of the controlling parameters. Then, the wider applicability of the method has been demonstrated by the analysis of the hot spot behaviour in a whole experimental campaign.

  • 22. Dumortier, P.
    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.
    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.
    Commissioning and first results of the reinstated JET ICRF ILA2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 285-288Article in journal (Refereed)
    Abstract [en]

    The JET ICRF ITER-like Antenna (ILA) has been operated at 33,42 and 47 MHz in 2008-2009 but stopped operation in 2009 due to the failure of one of the tuning capacitors inside the antenna. Tests on a spare capacitor showed that a micro-leak was caused by the cycle wear of a capacitor's internal bellows. The ILA was reinstated with a new operating scheme minimizing the full stroke requests of the capacitor. This contribution gives an overview of the works undertaken to reinstate the JET ILA up to the first results on plasma. The capacitors were replaced and high voltage tests of the capacitors were performed. An extensive calibration of all the measurements in the RF circuit was carried out. New simulation tools were created and control algorithms were implemented for the - toroidal and poloidal - phase control of the array as well as for the matching of the second stage. New protections are being implemented for the thermal and voltage protection of the capacitors. Low voltage matching tests were performed before the high power commissioning. Finally the first results on plasma are presented, showing that the new controls allow extending the range of the operation to lower (29 MHz) and higher (51 MHz) frequencies than previously achieved.

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    FULLTEXT01
  • 23. Fonnesu, N.
    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.
    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.
    The preparation of the Shutdown Dose Rate experiment for the next JET Deuterium-Tritium campaign2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1039-1043Article in journal (Refereed)
    Abstract [en]

    The assessment of the Shutdown Dose Rate (SDR) due to neutron activation is a major safety issue for fusion devices and in the last decade several benchmark experiments have been conducted at JET during Deuterium-Deuterium experiments for the validation of the numerical tools used in ITER nuclear analyses. The future Deuterium-Tritium campaign at JET (DTE2) will provide a unique opportunity to validate the codes under ITER-relevant conditions through the comparison between numerical predictions and measured quantities (C/E). For this purpose, a novel SDR experiment, described in the present work, is in preparation in the frame of the WPJET3-NEXP subproject within EUROfusion Consortium. The experimental setup has been accurately designed to reduce measurement uncertainties; spherical air-vented ionization chambers (ICs) will be used for on-line ex-vessel decay gamma dose measurements during JET shutdown following DT operations and activation foils have been selected for measuring the neutron fluence near ICs during operations. Active dosimeters (based on ICs) have been calibrated over a broad energy range (from about 30 keV to 1.3 MeV) with X and gamma reference beam qualities. Neutron irradiation tests confirmed the capability of active dosimeters of performing on-line decay gamma dose rate measurements, to follow gamma dose decay at the end of neutron irradiation as well as insignificant activation of the ICs. 

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    FULLTEXT01
  • 24. Fonnesu, 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.
    Shutdown dose rate measurements after the 2016 Deuterium-Deuterium campaign at JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1348-1353Article in journal (Refereed)
    Abstract [en]

    The EUROfusion Work Package JET3 programme, established to enable the technological exploitation of the JET experiments over the next years, includes, within the NEXP subproject, a novel Shutdown Dose Rate (SDR) experiment. Considering its ITER-relevance, SDR experiments at JET represent a unique opportunity to validate the numerical tools for ITER nuclear analysis, through the comparison between numerical predictions and measured quantities (C/E). Within this framework, two active gamma dosimeters based on spherical air-vented ionization chambers (ICs) have been installed in ex-vessel positions close to the horizontal ports of the tokamak in Octants 1 and 2. The first JET campaign exploited in the novel SDR experiment is the latest 5-week Deuterium-Deuterium campaign (c36b), which achieved the best results in recent years in terms of high power operation. The present work is dedicated to the analysis of dose rate measurements carried out during this campaign and after shutdown. Proper correction factors are evaluated and applied to the instrument reading, while influence quantities and error sources are analyzed in order to calculate the overall experimental uncertainty.

  • 25. Ghani, Z.
    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.
    Characterisation of neutron generators and monitoring detectors for the in-vessel calibration of JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 233-238Article in journal (Refereed)
    Abstract [en]

    A calibration of the JET neutron detectors was carried out prior to the upcoming deuterium-tritium experimental campaign. Two Compact DT neutron generators (NGs) were purchased for this purpose from VNIIA, Russia. These generators are capable of producing approximately 2 x 10(8) neutrons/s with a DT fusion energy spectrum. Preceding the in-vessel calibration measurements, these compact generators were tested and fully characterised at the UK's National Physical Laboratory (NPL). In order to support the characterisation measurements, detailed neutronics models were developed of the NGs, monitoring detectors and remote handling (RH) apparatus. Neutron spectra calculated from these models have been used to help determine NPL long counter efficiencies and effective centres, as well as NPL reference iron and aluminium activation foil reaction rates. The neutron emission rate has been measured for both generators as a function of angle using absolutely calibrated long counters and the relative emission rate by monitoring single crystal diamond detectors. The measured anisotropy profile is shown to be reproducible with a detailed NG MCNP model. Consequently, the neutron source routine and the MCNP model of the NGs can be reliably used for the analysis of the in-vessel calibration at JET.

  • 26.
    Giacomelli, L.
    et al.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Rigamonti, D.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Nocente, M.
    Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy.
    Rebai, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Tardocchi, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Franke, T.
    Max Planck Inst Plasma Phys, Garching, Germany;EUROfus Power Plant Phys & Technol PPPT Dept, Garching, Germany.
    Biel, W.
    Forschungszentrum Julich, Inst Energy & Climate Res, Julich, Germany;Univ Ghent, Dept Appl Phys, Ghent, Belgium.
    Conceptual studies of gamma ray diagnostics for DEMO control2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1494-1498Article in journal (Refereed)
    Abstract [en]

    The future tokamak demonstration fusion reactor (DEMO) will operate at unprecedented physical and technological conditions where high reliability of the system components is required. The conceptual study of a suite of DEMO diagnostics is on-going. Among these, a Gamma-Ray Spectrometric Instrument (GRSI) is being investigated to assess its performance and information quality in view of DEMO control. The GRSI foresees radial orthogonal multi-line of sight viewing DEMO plasma across its poloidal section as a further development of the Gamma-Ray Camera of JET and of the Radial Gamma-Ray Spectrometers proposed for ITER but with stricter technological constraints. These include surface availability in the Tritium Breeding Blankets of DEMO vessel inner wall for diagnostics collimators openings, diagnostics distance from the plasma, neutron irradiation and activation of the reactor structures. On DEMO the gamma-ray (gamma) emission from DT plasmas consists of T(d,gamma)He-5 (E gamma = 16.63 MeV) and T(p,gamma)He-4 (E gamma = 19.81 MeV) reactions which for their high E gamma would allow in principle for background-free measurements. This work reports the assessment on the GRSI diagnostic capability. Reactions cross sections are assessed and used for the calculations of the reactions gamma emission energy spectrum under DEMO DT plasma conditions and compared with 14 MeV neutron emissions before and after the GRSI collimator. Investigation of the GRSI gamma spectrometers performance is also presented. Measurement of the gamma emission intensity of T(d,gamma)He-5 can be in principle used as an independent assessment of DEMO DT plasmas fusion power.

  • 27. Giegerich, T.
    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.
    Advanced design of the Mechanical Tritium Pumping System for JET DTE22016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109-111, p. 359-364Article in journal (Refereed)
    Abstract [en]

    For tritium processing in JET during the next Deuterium-Tritium-Experiment (DTE2), a fully tritium compatible and continuously working vacuum pumping system has been developed. This pump train will be used as roughing pump to cover a pressure regime between 10(-1) Pa and ambient pressure. Therefore, a two-stage liquid ring pump in combination with a booster vapor diffusion pump will be applied. In this paper, a close-to-final design of the pumps is being described. Finite element (FEM) simulation results of components where high mechanical stresses due to thermal gradients are expected are presented. Furthermore, the final design of the control and data acquisition system is shown and explained.

  • 28. Glazunov, G.P.
    et al.
    Baron, D.I.
    Maznichenko, S.M.
    Moiseyenko, Volodymyr
    Institute of Plasma Physics of the National Science Center “Kharkov Institute of Physics and Technology”, 1, Academichna Street, 61108 Kharkiv, Ukraine.
    Bondarenko, M.N.
    Gnidenko, M.V.
    Gribanov, V.Yu.
    Konotopskiy, A.L.
    Kovtun, Yu.V.
    Kozulya, M.M.
    Yu Krasyuk, A.
    Listopad, V.M.
    Limar, N.V.
    Lozin, A.V.
    Ozherelev, F.I.
    Pashnev, V.K.
    Pavlichenko, R.O.
    Ponomarenko, N.P.
    Syusko, E.V.
    Lyssoivan, A.I.
    Wauters, T.
    Goriaev, A.
    Garkusha, I.E.
    Thermal desorption diagnostics in the Uragan-2M stellarator2021In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 170, article id 112716Article in journal (Refereed)
  • 29. Glazunov, G.P.
    et al.
    Baron, D.I.
    Moiseyenko, Volodymyr
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Bondarenko, M.N.
    Konotopskiy, A.L.
    Lozin, A.V.
    Lyssoivan, A.I.
    Wauters, T.
    Garkusha, I.E.
    Characterization of wall conditions in Uragan-2M stellarator using stainless steel thermal desorption probe2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 137, p. 196-201Article in journal (Refereed)
  • 30. Horton, Lorne
    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.
    JET experiments with tritium and deuterium-tritium mixtures2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109-111, p. 925-936Article in journal (Refereed)
    Abstract [en]

    Extensive preparations are now underway for an experiment in the Joint European Torus QET) using tritium and deuterium tritium mixtures. The goals of this experiment are described as well as the progress that has been made in developing plasma operational scenarios and physics reference pulses for use in deuterium tritium and full tritium plasmas. At present, the high performance plasmas to be tested with tritium are based on either a conventional ELMy H-mode at high plasma current and magnetic field (operation at up to 4 MA and 4T is being prepared) or the so-called improved H-mode or hybrid regime of operation in which high normalised plasma pressure at somewhat reduced plasma current results in enhanced energy confinement. Both of these regimes are being re-developed in conjunction with JET's ITER-like Wall (ILW) of beryllium and tungsten. The influence of the ILW on plasma operation and performance has been substantial. Considerable progress has been made on optimising performance with the all-metal wall. Indeed, operation at the (normalised) ITER reference confinement and pressure has been re-established in JET albeit not yet at high current. In parallel with the physics development, extensive technical preparations are being made to operate JET with tritium. The state and scope of these preparations is reviewed, including the work being done on the safety case for DT operation and on upgrading machine infrastructure and diagnostics. A specific example of the latter is the planned calibration at 14 MeV of JET neutron diagnostics.

  • 31.
    Huber, Alexander
    et al.
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Sergienko, Gennady
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Kinna, David
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Huber, Valentina
    Forschungszentrum Julich, Supercomp Ctr, D-52425 Julich, Germany..
    Milocco, Alberto
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Univ Milano Bicocca, Piazza Sci 3, I-20126 Milan, Italy..
    Mercadier, Laurent
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Balboa, Itziar
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cramp, Simon
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Kiptily, Vasili
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Kruezi, Uron
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Lambertz, Horst Toni
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Linsmeier, Christian
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Matthews, Guy
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Mertens, Philippe
    Forschungszentrum Julich, Inst Energie & Klimaforsch Plasmaphys, Trilateral Euregio Cluster, D-52425 Julich, Germany..
    Silburn, Scott
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Zastrow, Klaus-Dieter
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Response of the imaging cameras to hard radiation during JET operation2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 669-673Article in journal (Refereed)
    Abstract [en]

    The analysis of the radiation damage of imaging systems is based on all different types-of aiialoiue/digital cameras with uncooled as well as actively cooled image sensors in the VIS/NIR/MWIR spectral ranges. The Monte Carlo N-Particle (MCNP) code has been used to determine the neutron fluence at different camera locations in JET. An explicit link between the sensor damage and the neutron fluence has been observed. Sensors show an increased dark-current and increased numbers of hot-pixels. Uncooled cameras must be replaced once per year after exposure to a neutron fluence of similar to 1.9-3.2 x 10(12)neutrons/cm(2). Such levels of fluence will be reached after approximate to 14-22 ELMy H-mode pulses during the future D-T campaign. Furthermore, dynamical noise seen as a random pattern of bright pixels was observed in the presence of hard radiation (neutrons and gammas). Failure of the digital electronics inside the cameras as well as of industrial controllers is observed beyond a neutron fluence of about similar to 4 x 10(9) neutrons/cm(2). The impact of hard radiation on the different types of electronics and possible application of cameras during future D-T campaign is discussed.

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  • 32. Jednorog, S.
    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.
    Activation measurements in support of the 14 MeV neutron calibration of JET neutron monitors2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 125, p. 50-56Article in journal (Refereed)
    Abstract [en]

    In preparation for the upcoming deuterium-tritium campaign at the JET tokamak, the ex-vessel fission chamber neutron diagnostics and the neutron activation system will be calibrated in absolute terms at 14 MeV neutron energy, to a required accuracy of less than 10%. Two nominally identical DT neutron generators were chosen as the calibration sources, both of which were fully calibrated and characterized at the UK's National Physical Laboratory. The neutron activation method was adopted as a complementary method for the purpose of determining the absolute value of the neutron yield from the neutron generators and to provide a means of cross check for the active detection methods being employed. The work being presented here shows the derivation of the neutron emission rate from the neutron generators based upon experimental activation foil measurements.

  • 33.
    Kovtun, Yu.V.
    et al.
    Institute of Plasma Physics of the NSC KIPT, Kharkiv, Ukraine.
    Moiseyenko, Volodymyr
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Lozin, A.V.
    Kozulya, M.M.
    Pavlichenko, R.O.
    Zamanov, N.V.
    Shapoval, A.N.
    Bondarenko, V.N.
    Baron, D.I.
    Maznichenko, S.M.
    Korovin, V.B.
    Kramskoy, E.D.
    Siusko, Y.V.
    Romanov, V.S.
    Martseniuk, Yu.P.
    Krasiuk, A.Yu.
    Listopad, V.M.
    Garkusha, I.E.
    Alonso, A.
    Dinklage, A.
    Hartmann, D.
    Kazakov, Ye.
    Laqua, H.
    Ongena, J.
    Stange, T.
    Wauters, T.
    ICRF plasma production in gas mixtures in the Uragan-2M stellarator2023In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 194, article id 113887Article in journal (Refereed)
    Abstract [en]

    This paper summarizes previous results and presents new studies on the ICRF plasma creation both in pure gases and gas mixtures. In all the experiments, the two-strap antenna was operated in monopole phasing with applied RF power of ∼100 kW. The research for plasma creation was carried out at RF frequencies near the fundamental hydrogen cyclotron harmonic.

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  • 34. Kresina, Michal
    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.
    Preparation for commissioning of materials detritiation facility at Culham Science Centre2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 1391-1395Article in journal (Refereed)
    Abstract [en]

    The Materials Detritiation Facility has been designed to thermally treat solid non-combustible radioactive waste produced during operations of the Joint European Torus (JET) that is classified as Intermediate Level Waste in the UK due to its tritium inventory (> 12 kBq/g). The waste will be thermally treated in a retort furnace at temperatures up to 1000 degrees C under a flowing air atmosphere to reduce its tritium inventory sufficiently to allow its disposal at a lower waste category via existing disposal routes. The gaseous flow from the furnace will be processed via a bubbler system, where released tritium will be trapped in water. Commissioning of the facility will be divided into two main parts: inactive and active. The main purpose of the inactive commissioning is to verify that all components and safety systems of the facility are installed, tested and operated properly and within their operational limits. Several trials of the furnace with non-radioactive materials will be performed to verify its temperature profile, and to verify operation of the gaseous process line. During the active commissioning, small amounts of tritium-contaminated material will be introduced into the facility and used for active trials. The tritium inventory in this material has been selected based on the As low as reasonably practicable (ALARP) principle, to ensure that the activity levels are sufficient to fully test the control instrumentation and pose minimal risk to operators during commissioning. Overall, four active trials will be performed with carbon-based and Inconel materials with total tritium inventories of 1MBq, 3GBq, 20GBq and 26GBq. Tritium levels in the bubblers as well as in aerial discharge from the facility will be monitored. Furthermore, all materials used in the active trials will be sampled and analyzed to verify the performance of the process and confirm that a major part of tritium inventory can be removed from materials by the process.

  • 35. Kwiatkowski, R.
    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.
    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.
    Zoletnik, S.
    CeBr3-based detector for gamma-ray spectrometer upgrade at JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 986-989Article in journal (Refereed)
    Abstract [en]

    One of the important techniques used at JET for studying fast ions is based on measurements of gamma rays which are produced as a result of nuclear reactions between ions and plasma impurities. The intense neutron and gamma-ray fluxes expected during a DT campaign impose dew requirements on detector characteristics used in such experiments. In addition to good energy resolution, detectors must also be characterized by a high signal-to-noise ratio and allow to perform measurements at high counting rate about 1 Mcps. The scintillators which fulfill these requirements are, among others, LaBr3:Ce, already tested at JET, and CeBr3 with a scintillation decay time of similar to 20 ns. We report on measurements which were performed with a detector module equipped with a 3" x 3" CeBr3 scintillator and with an active voltage divider AVD@NCBJ, designed and constructed at NCBJ. Standard gamma -ray sources, as well as a PuBe source, were used for measurements. The comparison of measured and Monte Carlo simulated spectra is also presented. 

  • 36.
    Lengar, Igor
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Cufar, Aljaz
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Batistoni, Paola
    ENEA, Via E Fermi 45, I-00044 Rome, Italy.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova 39, SI-1000 Ljubljana, Slovenia.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Syme, Brian
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Vila, Rafael
    CIEMAT, Lab Nacl Fus, Madrid, Spain.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Stankunas, Gediminas
    Lithuanian Energy Inst, Lab Nucl Installat Safety, Breslaujos Str 3, LT-44403 Kaunas, Lithuania.;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England..
    Radiation damage and nuclear heating studies in selected functional materials during the JET DT campaign2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 1011-1015Article in journal (Refereed)
    Abstract [en]

    A new Deuterium-Tritium campaign (DTE2) is planned at JET in the next years, with a proposed 14 MeV neutron budget of 1.7 x 10(21), which is nearly an order of magnitude higher than any previous DT campaigns. The neutron and gamma ray fields inside the JET device during DT plasma operations at specific locations have previously been evaluated. It is estimated that a total neutron fluence on the first wall of JET of up to 10(20) n/m(2) could be achieved, which is comparable to the fluence occurring in ITER at the end of life in the rear part of the port plug, where several diagnostic components will be located. The purpose of the present work is to evaluate the radiation damage and nuclear heating in selected functional materials to be irradiated at JET during DT plasma operation. These quantities are calculated with the use of the MCNP6 code and the FISPACT II code. In particular the neutron and gamma ray fields at specific locations inside the JET device, dedicated to material damage studies, were characterized. The emphasis is on a potential longterm irradiation station located close to the first wall at outboard midplane, offering the opportunity to irradiate samples of functional materials used in ITER diagnostics, to assess the degradation of the physical properties. The radiation damage and the nuclear heating were calculated for selected materials irradiated in these positions and for the neutron flux and fluence expected in DTE2. The studied candidate functional materials include, among others, Sapphire, YAG, ZnS, Spinel, Diamond. In addition the activation of the internal irradiation holder itself was calculated with FISPACT. Damage levels in the range of 10(-5) dpa were found. 2016 EURATOM.

  • 37.
    Lengar, Igor
    et al.
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Cufar, Aljaz
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Radulovic, Vladimir
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Batistoni, Paola
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;ENEA, I-00044 Rome, Italy;CCFE, Abingdon OX14 3DB, Oxon, England.
    Popovichev, Sergey
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Packer, Lee
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Ghani, Zamir
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;CCFE, Abingdon OX14 3DB, Oxon, England.
    Kodeli, Ivan A.
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England.
    Snoj, Luka
    EUROfus Consortium, Culham Sci Ctr, Abingdon, Oxon, England;Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia.
    Activation material selection for multiple foil activation detectors in JET TT campaign2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 136, p. 988-992Article in journal (Refereed)
    Abstract [en]

    In the preparation for the Deuterium-Tritium campaign, JET will operate with a tritium plasma. The T + T reaction consists of two notable channels: (1) T + T -> He-4 + 2n, (2) T + T -> He-5 + n -> He-4 + 2n. The reaction channel (1) is the reaction with the highest branching ratio and a continuum of neutron energies being produced. Reaction channel (2) produces a spectrum with a peak at 8.8 MeV. A particular problem is the ratio between the individual TT reaction channels, which is highly dependent on the energy of the reacting tritium ions. There are very few measurements on the TT spectrum and the study at JET would be interesting. The work is focused on the determination of the spectral characteristics in the TT plasma discharges, especially on the presence of the 8.8 MeV peak, a consequence of channel (2) of the TT reaction. The possibility to use an optimized set of activation materials in order to target the measurement of the 8.8 MeV peak is studied. The lower limit of detection for the channel (2) ratio within the TT reaction is estimated and the influence of DT source neutrons, which are a consequence of deuterium traces in the plasma, is investigated.

  • 38.
    Lengar, Igor
    et al.
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, Ljubljana, Slovenia.
    Zohar, Andrej
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;Jozef Stefan Inst, Reactor Phys Div, Jamova Cesta 39, Ljubljana, Slovenia.
    Batistoni, Paola
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;ENEA, Fus Tech Unit, Via E Fermi 45, I-00044 Frascati, Italy;Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.
    Popovichev, Sergey
    Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England;Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, Abingdon, Oxon, England.
    Characterization of JET neutron field in irradiation locations for DD, DT and TT plasmas2019In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 146, p. 1967-1970Article in journal (Refereed)
    Abstract [en]

    The neutron fluxes and spectra were characterized for four locations close to the plasma and related to activation experiments, as the preparation for the upcoming experimental campaigns in JET. The focus was on the study of a variance reduction technique in order to obtain statistically significant results in the parts of the neutron energy spectra, important for irradiation experiments. The DD, DT and TT plasmas were studied with the Monte Carlo hybrid method and the use of the ADVANTG program for generation of weight windows as variance reduction method to accelerate Monte Carlo simulations. The calculations were optimized to obtain low statistical uncertainties for all energy bins in the 640 energy group structure and for all three plasma sources. This included the acceleration of calculations for reaction rates of capture reactions, i.e. in the thermal flux region in irradiation positions on the first wall. Speed-ups due to use of the hybrid method in excess of two orders of magnitude were found with respect to analog calculations despite the vicinity of the plasma source.

  • 39. Lennholm, M.
    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.
    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.
    Real time control developments at JET in preparation for deuterium-tritium operation2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 535-540Article in journal (Refereed)
    Abstract [en]

    Robust high performance plasma scenarios are being developed to exploit the unique capability of JET to operate with Tritium and Deuterium. In this context, real time control schemes are used to guide the plasma into the desired state and maintain it there. Other real time schemes detect undesirable behaviour and trigger appropriate actions to assure the best experimental results without unnecessary use of the limited neutron and Tritium budget. This paper discusses continuously active controllers and event/threshold detection algorithms triggering a variety of actions. Recent advances include: (i) Control of the degree of plasma detachment via impurity injection; (ii) ELM frequency control via gas/Pellet injection; (iii) Sawtooth pacing using ICRH modulation, (iv) control of the Hydrogen to Deuterium isotope ratio through gas injection and (v) the determination that a discharge is not evolving as desired, triggering a cascade of actions attempting to stop the plasma rapidly and safely, eventually triggering massive gas injection if a disruption is deemed unavoidable. For high power Deuterium-Tritium operation these control schemes need to be integrated into the plasma scenarios ensuring that they are mutually compatible. 

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  • 40.
    Lungaroni, M.
    et al.
    Univ Roma Tor Vergata, Dept Ind Engn, Via Politecn 1, Rome, Italy.
    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.
    Natl Ctr Nucl Res, Otwock, Poland.
    On the potential of ruled-based machine learning for disruption prediction on JET2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 130, p. 62-68Article in journal (Refereed)
    Abstract [en]

    In the last years, it has become apparent that detecting disruptions with sufficient anticipation time is an essential but not exclusive task of predictors. It is also important that the prediction is accompanied by appropriate qualifications of its reliability and it is formulated in mathematical terms appropriate for the task at hand (mitigation, avoidance, classification etc.). In this paper, a wide series of rule-based predictors, of the Classification and Regression Trees (CART) family, have been compared to assess their relative merits. An original refinement of the training, called noise-based ensembles, has allowed not only to obtain significantly better performance but also to increase the interpretability of the results. The final predictors can indeed be represented by a tree or a series of specific and clear rules. Such performance has been proved by analysing large databases of shots on JET with both the carbon wall and the ITER Like Wall. In terms of performance, the developed tools are therefore very competitive with other machine learning techniques, with the specificity of formulating the final models in terms of trees and simple rules.

  • 41.
    Marcinkevicius, Benjaminas
    et al.
    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.
    Hjalmarsson, Anders
    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.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Benjamin (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hägg, Linus (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Primetzhofer, Daniel (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sahlberg, Arne (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias (Contributor)
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fuel ion ratio determination using the 14 MeV Tandem neutron spectrometer for JET DTE1 campaign discharges2022In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 184, article id 113259Article in journal (Refereed)
    Abstract [en]

    This paper investigates the determination of the fuel ion ratio nT/ntot in fusion experiments using two different approaches. The methods are applied to plasma discharges from the deuterium-tritium campaign at the Joint European Torus (JET) in 1997. Multiple discharges have been analysed using data acquired with the Tandem (KM2) neutron spectrometer, using a new neutron spectrometer response function and improved line-of-sight information.The two different approaches were generally similar with the exception of the beam slowing down modelling, handled by two different particle transport codes, namely, TRANSP and PENCIL.The results show that nT/ntot can be determined using Tandem neutron spectrometer data; nT/ntot using both of the approaches are consistent and within the uncertainty for a range of studied discharges.The obtained results support previous studies on nT/ntot determination using neutron spectroscopy. In addition, we have shown that PENCIL can be used instead of TRANSP for a range of discharges which could simplify and speed up the estimation of nT/ntot. The possible limitations of the approach using PENCIL could be investigated using different neutron spectrometer data from the 2021 JET deuterium-tritium campaign.A similar spectrometer like Tandem is planned to be operational at ITER and the results of this paper form the first experimental verification of the capability for nT/ntot measurements with such spectrometers. Further research on this could lead to better understanding of these instruments and their limitations before the start of experiments at ITER.

  • 42. Matos, Francisco A.
    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.
    Deep learning for plasma tomography using the bolometer system at JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 114, p. 18-25Article in journal (Refereed)
    Abstract [en]

    Deep learning is having a profound impact in many fields, especially those that involve some form of image processing. Deep neural networks excel in turning an input image into a set of high-level features. On the other hand, tomography deals with the inverse problem of recreating an image from a number of projections. In plasma diagnostics, tomography aims at reconstructing the cross-section of the plasma from radiation measurements. This reconstruction can be computed with neural networks. However, previous attempts have focused on learning a parametric model of the plasma profile. In this work, we use a deep neural network to produce a full, pixel-by-pixel reconstruction of the plasma profile. For this purpose, we use the overview bolometer system at JET, and we introduce an up-convolutional network that has been trained and tested on a large set of sample tomograms. We show that this network is able to reproduce existing reconstructions with a high level of accuracy, as measured by several metrics.

  • 43. Moro, F.
    et al.
    Esposito, B.
    Marocco, D.
    Villari, R.
    Petrizzi, L.
    Andersson Sundén, Erik
    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.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dapena, M.
    Neutronic calculations in support of the design of the ITER High Resolution Neutron Spectrometer2011In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 86, no 6-8, p. 1277-1281Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of neutronic calculations performed to address important issues related to the optimization of the ITER HRNS (High resolution Neutron Spectrometer) design, in particular concerning the definition of the collimator and the choice of the detector system. The calculations have been carried out using the MCNP5 Monte Carlo code in a full 3-D geometry. The HRNS collimation system has been included in the latest MCNP ITER 40 model (Alite-4). The ITER scenario 2 reference DT plasma fusion neutron source peaked at 14.1 MeV with Gaussian energy distribution has been used. Neutron fluxes and energy spectra (>1 MeV) have been evaluated at different positions along the HRNS collimator and at the detector location. The noise-to-signal ratio (i.e. the ratio of collided to uncoilided neutrons), the breakdown of the collided spectrum into its components, the dependency on the first wall aperture and the gamma-ray spectra at the detector position have also been analyzed. The impact of the results on the design of the HRNS diagnostic system is discussed.

  • 44.
    Moro, Fabio
    et al.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Marocco, D.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Esposito, B.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Flammini, D.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Podda, S.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Villari, R.
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nuclear analysis of the ITER radial neutron camera architectural options2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1033-1038Article in journal (Refereed)
    Abstract [en]

    The ITER Radial Neutron Camera (RNC) is a multichannel detection system hosted in the Equatorial Port Plug 1 (EPP 1) designed to provide information on the neutron source total strength arid emissivity profiles. It consists of two sub-systems: the ex-port line-of-sights (LOSs), covering the plasma core, embedded in a massive shielding block located in the Port Interspace, and the in-port LOSs distributed in two removable cassettes integrated inside the Port Plug. Presently, the RNC layout development process is undergoing a System Level Design phase: several preliminary architectural options based on a System Engineering work have been defined: a detailed nuclear analysis of these options has been performed through radiation transport calculations with the MCNP Monte Carlo code. The radiation environment at the detectors positions has been fully characterized through the evaluation of the expected neutron spectra and the secondary gamma background and the analysis of the 3D radiation maps. MoreOver, the impact of a reduced ex-port shielding block on the neutron and gamma spectra has been investigated. The results of the present study provide guidelines for the development of the RNC final design and the necessary data for the measurement performance analysis.

  • 45. Obryk, Barbara
    et al.
    Batistoni, Paola
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Syme, Brian D.
    Popovichev, Sergey
    Stamatelatos, Ion E.
    Vasilopoulou, Theodora
    Bilski, Pawel
    Thermoluminescence measurements of neutron streaming through JET Torus Hall ducts2014In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 89, no 9-10, p. 2235-2240Article in journal (Refereed)
    Abstract [en]

    Thermoluminescence detectors (TLD) were used for dose measurements at JET. Several hundreds of LiF detectors of various types, standard LiF:Mg,Ti and highly sensitive LiF:Mg,Cu,P were produced. LiF detectors consisting of natural lithium are sensitive to slow neutrons, their response to neutrons being enhanced by Li-6-enriched lithium or suppressed by using lithium consisting entirely of Li-7. Pairs of (LiF)-Li-6/(LiF)-Li-7 detectors allow distinguishing between neutron/non-neutron components of a radiation field. For detection of neutrons of higher energy, polyethylene (PE-300) moderators were used. TLDs, located in the centre of cylindrical moderators, were installed at eleven positions in the JET hall and the hall labyrinth in July 2012, and exposure took place during the last two weeks of the experimental campaign. Measurements of the gamma dose were obtained for all positions over a range of about five orders of magnitude variation. As the TLDs were also calibrated in a thermal neutron field, the neutron fluence at the experimental position could be derived. The experimental results are compared with calculations using the MCNP code. The results confirm that the TLD technology can be usefully applied to measurements of neutron streaming through JET Torus Hall ducts.  

  • 46. Oya, Yasuhisa
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, F.
    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, N.
    Ericsson, G.
    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. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, The Svedberg Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy 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, M.
    Zychor, I.
    Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall2018In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 132, p. 24-28Article in journal (Refereed)
    Abstract [en]

    To understand the fuel retention mechanism correlation of surface chemical states and hydrogen isotope retention behavior determined by XPS (X-ray photoelectron spectroscopy) and TDS (Thermal desorption spectroscopy), respectively, for JET ITER-Like Wall samples from operational period 2011-2012 were investigated. It was found that the deposition layer was formed on the upper part of the inner vertical divertor area. At the inner plasma strike point region, the original surface materials, W or Mo, were found, indicating to an erosion-dominated region, but deposition of impurities was also found. Higher heat load would induce the formation of metal carbide. At the outer horizontal divertor tile, mixed material layer was formed with iron as an impurity. TDS showed the H and D desorption behavior and the major D desorption temperature for the upper part of the inner vertical tile was located at 370 degrees C and 530 degrees C. At the strike point region, the D desorption temperature was clearly shifted toward higher release temperatures, indicating the stabilization of D trapping by higher heat load

  • 47. Packer, L. W.
    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.
    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.
    Status of ITER material activation experiments at JET2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 124, p. 1150-1155Article in journal (Refereed)
    Abstract [en]

    Activities under the EURO fusion work package JET3 programme have been established to enable the technological exploitation of the planned JET experiments over the next few years, which culminates in a D-T experimental campaign, DTE-2. In the areas of nuclear technology and nuclear safety the programme offers a unique opportunity to provide experimental data that is relevant to ITER. The key purpose of the collected data will be to support bench marking and validation activities relating to neutronics and activation codes, and associated nuclear data, that are used to predict the nuclear behavior of ITER component and materials, during and after operations. This paper details the status and key issues of the ongoing ACT sub-project under work package JET3, which aims to take advantage of the large 14 MeV neutron fluence expected during JET DTE-2 to irradiate samples of real ITER materials used in the manufacturing of the main in-vessel tokamak components. The materials considered, with specified minor elemental impurity levels, include: Nb3Sn, SS316L steels from a range of manufacturers, SS304B, Alloy 660, W, CuCrZr, OF-Cu, XM-19, Al bronze, NbTi and EUROFER. The activities include provision for measurement of nuclide activities for each material and comparison against the predicted quantities through calculation with the FISPACT-II inventory code. Included here are key pre-analysis results for the selected ITER irradiation samples, and corresponding optimization of dosimetry foils (Ti, Mn, Co, Ni, Y, Fe, Co, Sc, Ta) that will be irradiated at selected positions inside JET irradiation stations in order to determine the neutron spectrum. Preliminary experimental activation results through recent JET D-D operations are discussed. 

  • 48. Pau, A.
    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.
    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.
    A tool to support the construction of reliable disruption databases2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 125, p. 139-153Article in journal (Refereed)
    Abstract [en]

    An algorithm for detection and automatic calculation of disruption main quantities has been proposed and tested on the discharges of recent campaigns in both JET and ASDEX Upgrade. The purpose of this paper is to describe a tool to support the construction of a reliable database, which is theoretically applicable to a wide variety of tokamaks and can support the operators in a very time consuming activity, reducing significantly the possibility of human errors. The algorithm performs its calculations on the basis of common and well defined criteria discussed with the Plasma and Control Operation Groups of the considered devices. Moreover, being the algorithm fully parameterized, it can be easily customized to other tokamaks and/or used for statistical purposes, according to criteria adopted in the framework of each study.

  • 49. Pillon, Mario
    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.
    Characterization of a diamond detector to be used as neutron yield monitor during the in-vessel calibration of JET neutron detectors in preparation of the DT experiment2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 106, p. 93-98Article in journal (Refereed)
    Abstract [en]

    A new Deuterium-Tritium (DT) campaign is planned at JET. An accurate calibration for the 14 MeV neutron yield monitors is necessary. In order to perform the calibration a 14 MeV Neutron Generator with suitable intensity (similar to 10(8) n/s) will be used. Due to the intensity change during the Neutron Generator lifetime it would be necessary to monitor continuously the neutron emission intensity during the calibration using a compact detector attached to it. A high quality diamond detector has been chosen as one of the monitors. This detector has been fully characterized at the 14 MeV Frascati Neutron Generator facility. The characterization procedure and the resulting 14 MeV neutron response of the detector are described in this paper together with the obtained uncertainties. (C) 2016 Elsevier B.V. All rights reserved.

  • 50. Ratta, G. A.
    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.
    Global optimization driven by genetic algorithms for disruption predictors based on APODIS architecture2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 112, p. 1014-1018Article in journal (Refereed)
    Abstract [en]

    Since year 2010, the APODIS architecture has proven its accuracy predicting disruptions in JET tokamak. Nevertheless, it has shown margins for improvements, fact indisputable after the enhanced performances achieved in posterior upgrades. In this article, a complete optimization driven by Genetic Algorithms (GA) is applied to it aiming at considering all possible combination of signals, signal features, quantity of models, their characteristics and internal parameters. This global optimization targets the creation of the best possible system with a reduced amount of required training data. The results harbor no doubts about the reliability of the global optimization method, allowing to outperform the ones of previous versions: 91.77% of predictions (89.24% with an anticipation higher than 10 ms) with a 3.55% of false alarms. Beyond its effectiveness, it also provides the potential opportunity to develop a spectrum of future predictors using different training datasets. 

12 1 - 50 of 77
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