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  • 1.
    Andersson, Pernilla
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bevilacqua, Riccardo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Blomgren, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, The Svedberg Laboratory.
    Kolozhvari, A.
    LeColley, F. -R
    Marie, Nathalie
    Uppsala University, The Svedberg Laboratory.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander V.
    Uppsala University, The Svedberg Laboratory.
    Simutkin, Vasily D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tesinsky, Milan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tippawan, U.
    An upgrade of the SCANDAL setup for measurements of elastic neutron scattering at 175 MeV2010In: Radiation Measurements, ISSN 1350-4487, E-ISSN 1879-0925, Vol. 45, no 10, p. 1142-1144Article in journal (Refereed)
    Abstract [en]

    The experimental setup SCANDAL used for measurements of the differential cross section for elastic and inelastic neutron scattering, has recently been upgraded with larger CsI scintillating detectors to enable measurements at energies up to 175 MeV. Measurements on Fe. Bi and Si have been carried out using the quasi mono-energetic neutron beam at the The Svedberg Laboratory, and data is under analysis. The experimental setup can be used for measurements on a wide range of target nuclei, including C and O, which are important for dosimetry applications. SCANDAL can also run in proton mode, for measurements of the (n,p) reaction. This paper describes the new experimental setup, and reports on its properties, such as energy resolution.

  • 2.
    Andersson Sunden, E
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    Murari, A
    Popovichev, S
    Sousa, J
    Pereira, R.C
    Combo, A
    Cruz, N
    JET EFDA contributors,
    Neutron emission spectroscopy diagnosis of JET D and DT plasmas with the new MPRu instrument2006In: 33rd EPS Conference on Plasma Phys. and Contr. Fusion, 2006, p. 30I P-1.071Conference paper (Refereed)
  • 3.
    Andersson Sundén, E
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    Evaluation of Spectral Unfolding for Neutron Spectroscopy2007Report (Other (popular scientific, debate etc.))
  • 4. Batistoni, 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.
    14 MeV calibration of JET neutron detectors-phase 1: calibration and characterization of the neutron source2018In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 58, no 2, article id UNSP 026012Article in journal (Refereed)
    Abstract [en]

    In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is +/- 10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4 pi sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within +/- 5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in-vessel calibration and to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the generator neutrons, and taking into account all the calibration circumstances.

  • 5.
    Bevilacqua, Riccardo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simutkin, V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hayashi, M.
    Hirayama, S.
    Naitou, Y.
    Watanabe, Y.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Tippawan, U.
    Lecolley, F. -R
    Marie, N.
    Leray, S.
    David, J. -C
    Mashnik, S.
    Light-ion Production from O, Si, Fe and Bi Induced by 175 MeV Quasi-monoenergetic Neutrons2014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. 190-193Article in journal (Refereed)
    Abstract [en]

    We have measured double-differential cross sections in the interaction of 175 MeV quasimonoenergetic neutrons with O, Si, Fe and Bi. We have compared these results with model calculations with INCL4.5-Abla07, MCNP6 and TALYS-1.2. We have also compared our data with PHITS calculations, where the pre-equilibrium stage of the reaction was accounted respectively using the JENDL/HE-2007 evaluated data library, the quantum molecular dynamics model (QMD) and a modified version of QMD (MQMD) to include a surface coalescence model. The most crucial aspect is the formation and emission of composite particles in the pre-equilibrium stage.

  • 6. Bevilacqua, Riccardo
    et al.
    Pomp, Stephan
    Simutkin, Vasily
    Tippawan, Udomrat
    Andersson, Pernilla
    Blomgren, Jan
    Osterlund, Michael
    Hayashi, Masateru
    Hirayama, Shusuke
    Naito, Yuuki
    Watanabe, Yukinobu
    Tesinsky, Milan
    LeColley, Francois-Rene
    Marie, Nathalie
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander V.
    Uppsala University, The Svedberg Laboratory.
    Kolozhvari, Anatoly
    Neutron induced light-ion production from Iron and Bismuth at 175 MeV2010In: CNR '09: SECOND INTERNATIONAL WORKSHOP ON COMPOUND NUCLEAR REACTIONS AND RELATED TOPICS, 2010, article id 05005Conference paper (Refereed)
    Abstract [en]

    We have measured light-ion (p, d, t, He-3 and alpha) production in the interaction of 175 MeV neutrons with iron and bismuth, using the MEDLEY setup. A large set of measurements at 96 MeV has been recently completed and published, and now higher energy region is under investigation. MEDLEY is a conventional spectrometer system that allows low-energy thresholds and offers measurements over a wide angular range. The system consists of eight telescopes, each of them composed of two silicon surface barrier detectors, to perform particle identification, and a Csl(Tl) scintillator to fully measure the kinetic energy of the produced light-ions. The telescopes are placed at angles from 20 degrees to 160 degrees, in steps of 20 degrees. Measurements have been performed at The Svedberg Laboratory, Uppsala (Sweden), where a quasi mono-energetic neutron beam is available and well characterized. Time of flight techniques are used to select light-ion events induced by neutrons in the main peak of the source neutron spectrum. We report preliminary double differential cross sections for production of protons, deuterons and tritons in comparison with model calculations using TALYS-1.0 code.

  • 7.
    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.
    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.
    Eriksson, Jacob
    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.
    Conroy, Sean
    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.
    Monte Carlo Simulation Of The Data Acquisition Chain Of Scintillation Detectors2014In: International Conference on Fusion Reactor Diagnostics, SEP 09-13, 2013, Varenna, ITALY, 2014, p. 101-104Conference paper (Refereed)
    Abstract [en]

    The good performance of a detector can be strongly affected by the instrumentation used to acquire the data. The possibility of anticipating how the acquisition chain will affect the signal can help in finding the best solution among different set-ups. In this work we developed a Monte Carlo code that aims to simulate the effect of the various components of a digital Data Acquisition system (DAQ) applied to scintillation detectors. The components included in the model are: the scintillator, the photomultiplier tube (PMT), the signal cable and the digitizer. We benchmarked the code against real data acquired with a NE213 scintillator, comparing simulated and real signal pulses induced by gamma-ray interaction. Then we studied the dependence of the energy resolution of a pulse height spectrum (PHS) on the sampling frequency and the bit resolution of the digitizer. We found that exceeding some values of the sampling frequency and the bit resolution improves only marginally the performance of the system. The method can be applied for the study of various detector systems relevant for nuclear techniques, such as in fusion diagnostics.

  • 8. Cazzaniga, C.
    et al.
    Cremona, A.
    Nocente, M.
    Rebai, M.
    Rigamonti, D.
    Tardocchi, M.
    Croci, G.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fazzi, A.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mazzocco, M.
    Strano, E.
    Gorini, G.
    Light response of YAP:Ce and LaBr3:Ce scintillators to 4-30 MeV protons for applications to Telescope Proton Recoil neutron spectrometers2016In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 820, p. 85-88Article in journal (Refereed)
    Abstract [en]

    The light response of two thin inorganic scintillators based on YAP:Ce and LaBr3:Ce crystals has been measured with protons in the 4-8 MeV energy range at the Uppsala tandem accelerator and in the 826 MeV energy range at the Legnaro tandem accelerator. The crystals have been calibrated in situ with Cs-137 and Co-60 gamma-ray sources. The relative light yields of protons with respect to gammas have been measured and are here reported to be (96 +/- 2)% and (80 +/- 2)% for YAP:Ce and LaBr3:Ce, respectively. The results open up to the development of a Telescope Proton Recoil spectrometer based on either of the two crystals as alternative to a silicon based spectrometer for applications to high neutron fluxes.

  • 9. Cazzaniga, C.
    et al.
    Nocente, M.
    Tardocchi, M.
    Fazzi, A.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rigamonti, D.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G.
    Thin YAP:Ce and LaBr3:Ce scintillators as proton detectors of a thin-film proton recoil neutron spectrometer for fusion and spallation sources applications2014In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 751, p. 19-22Article in journal (Refereed)
    Abstract [en]

    Two thin inorganic scintillators based on YAP and LaBr3 crystals (1 in, diameter x 0.1 in, height) have been used for proton measurements at the Uppsala tandem accelerator in the energy range 4-8 MeV. Measurements show a comparable good energy resolution for the two detectors, better than 2% (FWHM) for 8 MeV protons, which compares to 3.8% (LaBr3) and 3.7% (YAP) obtained at the 1.3 MeV peak of a Co-60 gamma-ray source. The main advantages of these crystals are a fast scintillation time (less than 30 ns), an excellent light yield and the capability to operate in large neutron background, which make them ideal candidates as proton detectors of a thin-film proton recoil neutron spectrometer for application on fusion experiments and fast neutron spallation sources.

  • 10. Cazzaniga, C.
    et al.
    Tardocchi, M.
    Croci, G.
    Frost, C.
    Giacomelli, L.
    Grosso, G.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rebai, M.
    Rhodes, N. J.
    Schooneveld, E. M.
    Gorini, G.
    First measurement of the VESUVIO neutron spectrum in the 30-80 MeV energy range using a Proton Recoil Telescope technique2013In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 8, p. P11008-Article in journal (Refereed)
    Abstract [en]

    Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV < E-n < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum.

  • 11.
    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.

  • 12.
    Dzysiuk, Nataliia
    et al.
    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.
    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.
    Hjalmarsson, Anders
    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.
    Design of a Backscatter 14-MeV Neutron Time-of-Flight Spectrometer for Experiments at ITER2014In: Fusion Reactor Diagnostics / [ed] Gorini, G; Orsitto, FP; Sozzi, C; Tardocchi, M, 2014, Vol. 1612, p. 145-148Conference paper (Refereed)
    Abstract [en]

    Neutron energy spectrometry diagnostics play an important role in present-day experiments related to fusion energy research. Measurements and thorough analysis of the neutron emission from the fusion plasma give information on a number of basic fusion performance quantities, on the condition of the neutron source and plasma behavior. Here we discuss the backscatter Time-of-Flight (bTOF) spectrometer concept as a possible instrument for performing high resolution measurements of 14 MeV neutrons. The instrument is based on two sets of scintillators, a first scatterer exposed to a collimated neutron beam and a second detector set placed in the backward direction. The scintillators of the first set are enriched in deuterium to achieve neutron backscattering. The energy resolution and efficiency of a bTOF instrument have been determined for various geometrical configurations. A preliminary design of optimal geometry for the two scintillator sets has been obtained by Monte Carlo simulations based on the MCNPX code.

  • 13.
    Ericsson, G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sunden, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Wikström, G
    Gorini, G
    Tardocchi, M
    Pereira, R.C
    Combo, A
    Cruz, N
    Sousa, J
    Correia, C
    Popovichev, S
    JET EFDA contributors,
    Upgrade of the Magnetic Proton Recoil (MPRu) spectrometer for 1.5-18 MeV neutrons for JET and the next step2006In: Workshop on Fast Neutron Detection and Applications,, 2006, p. 039-Conference paper (Refereed)
  • 14.
    Ericsson, G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ognissanto, F
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Angelone, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Popovichev, S
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Prospects for High Resolution Neutron Spectroscopy on High Power Fusion Devices in View of the Recent Diagnostic Developments at JET2008In: AIP Conference Proceedings 988, 2008, p. 307-Conference paper (Refereed)
  • 15.
    Ericsson, G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Ognissanto, F
    Tardocchi, M
    Angelone, M
    Popovichev, S
    Prospects for High Resolution Neutron Spectroscopy on High Power Fusion Devices in View of the Recent Diagnostic Developments at JET2007Report (Other (popular scientific, debate etc.))
  • 16.
    Eriksson, Jacob
    et al.
    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.
    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.
    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.
    Lerche, E.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Van Eester, D.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Neutron spectrometry measurements of energetic deuterons in ICRF heated plasmas with the ITER-like wall at JET2014In: 41th EPS Conference on Plasma Physics 2014 (EPS 2014): Europhysics Conference Abstracts, 2014Conference paper (Other academic)
    Abstract [en]

    At JET, experiments have been conducted in order to optimize the performance of ion cyclotron radio-frequency (ICRF) heating in the presence of the newly installed ITER-like wall. The ICRF was tuned to the cyclotron frequency of minority hydrogen (H), which is also the 2nd harmonic of the cyclotron frequency of deuterium (D). The relative H concentration was varied from a few percent up to about 25 percent in a series of plasma discharges and the neutron time-of-flight spectrometer TOFOR was used to measure the energy spectrum of neutrons from the D(D,n)3He reaction during these discharges. It could be seen that the signal from ICRF accelerated deuterons depended strongly on H concentration. This observation indicates that the ICRF power absorbed by D at the 2nd harmonic cyclotron resonance increases with decreasing H concentration. This is in qualitative agreement with theoretical expectations obtained from the plasma wave equation solver TOMCAT.

  • 17.
    Eriksson, Jacob
    et al.
    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.
    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.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L.
    CNR, Ist Fis Plasma, Milan, Italy.
    Gorini, G.
    CNR, Ist Fis Plasma, Milan, Italy;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kiptily, V. G.
    Culham Sci Ctr, CCFE, Abingdon, Oxon, England.
    Mantsinen, M.
    BSC, Barcelona, Spain;ICREA, Pg Llus Companys 23, E-08010 Barcelona, Spain.
    Nocente, M.
    CNR, Ist Fis Plasma, Milan, Italy;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy.
    Sahlberg, Arne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Salewski, M.
    Tech Univ Denmark, Dept Phys, Lyngby, Denmark.
    Sharapov, S.
    Culham Sci Ctr, CCFE, Abingdon, Oxon, England.
    Tardocchi, M.
    CNR, Ist Fis Plasma, Milan, Italy.
    Measuring fast ions in fusion plasmas with neutron diagnostics at JET2019In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 61, no 1, article id 014027Article in journal (Refereed)
    Abstract [en]

    Fast ions in fusion plasmas often leave characteristic signatures in the neutron emission from the plasma. In this paper, we show how neutron measurements can be used to study fast ions and give examples of physics results obtained on present day tokamaks. The focus is on measurements with dedicated neutron spectrometers and with compact neutron detectors used in each channel of neutron profile monitors. A measured neutron spectrum can be analyzed in several different ways, depending on the physics scenario under consideration. Gross features of a fast ion energy distribution can be studied by applying suitably chosen thresholds to the measured spectrum, thus probing ions with different energies. With this technique it is possible to study the interaction between fast ions and MHD activity, such as toroidal Alfven eigenmodes (TAEs) and sawtooth instabilities. Quantitative comparisons with modeling can be performed by a direct computation of the neutron emission expected from a given fast ion distribution. Within this framework it is also possible to determine physics parameters, such as the supra-thermal fraction of the neutron emission, by fitting model parameters to the data. A detailed, model-independent estimate of the fast ion distribution can be obtained by analyzing the data in terms of velocity space weight functions. Using this method, fast ion distributions can be resolved in both energy and pitch by combining neutron and gamma-ray measurements obtained along several different sightlines. Fast ion measurements of the type described in this paper will also be possible at ITER, provided that the spectrometers have the dynamic range required to resolve the fast ion spectral features in the presence of the dominating thermonuclear neutron emission. A dedicated high-resolution neutron spectrometer has been designed for this purpose.

  • 18.
    Eriksson, Jacob
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nocente, Massimo
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cazzaniga, Carlo
    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.
    Gorini, Giuseppe
    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.
    Sharapov, Sergei
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, Marco
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET2015In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 12, article id 123026Article in journal (Refereed)
    Abstract [en]

    Observations made in a JET experiment aimed at accelerating deuterons to the MeV range by third harmonic radio-frequency (RF) heating coupled into a deuterium beam are reported. Measurements are based on a set of advanced neutron and gamma-ray spectrometers that, for the first time, observe the plasma simultaneously along vertical and oblique lines of sight. Parameters of the fast ion energy distribution, such as the high energy cut-off of the deuteron distribution function and the RF coupling constant, are determined from data within a uniform analysis framework for neutron and gamma-ray spectroscopy based on a one-dimensional model and by a consistency check among the individual measurement techniques. A systematic difference is seen between the two lines of sight and is interpreted to originate from the sensitivity of the oblique detectors to the pitch-angle structure of the distribution around the resonance, which is not correctly portrayed within the adopted one dimensional model. A framework to calculate neutron and gamma-ray emission from a spatially resolved, two-dimensional deuteron distribution specified by energy/pitch is thus developed and used for a first comparison with predictions from ab initio models of RF heating at multiple harmonics.

    The results presented in this paper are of relevance for the development of advanced diagnostic techniques for MeV range ions in high performance fusion plasmas, with applications to the experimental validation of RF heating codes and, more generally, to studies of the energy distribution of ions in the MeV range in high performance deuterium and deuterium-tritium plasmas.

  • 19.
    Gatu Johnson, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    Combo, A
    Cruz, N
    Sousa, J
    Popovichev, S
    The 2.5 MeV Neutron Time-of-Flight Spectrometer TOFOR for Experiments at JET2007Report (Other (popular scientific, debate etc.))
  • 20.
    Gatu Johnson, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    The TOFOR Neutron Spectrometer for High Performance Measurements of D Plasma Fuel Ion Properties2008In: AIP Conference Proceedings 988, 2008, p. 311-Conference paper (Refereed)
  • 21.
    Gatu Johnson, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    The TOFOR Neutron Spectrometer for High-Performance Measurements of D Plasma Fuel Ion Properties2007Report (Other (popular scientific, debate etc.))
  • 22.
    Gatu Johnson, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    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.
    Källne, Jan
    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, Technology, Department of Engineering Sciences, Electricity.
    Weiszflog, Matthias
    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.
    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.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, Emanuele
    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.
    Gorini, G
    Tardocchi, M
    Combo, A
    Cruz, N
    Sousa, J
    Popovichev, S
    The 2.5-MeV neutron time-of-flight spectrometer TOFOR for experiments at JET2008In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 591, no 2, p. 417-430Article in journal (Refereed)
    Abstract [en]

    A time-of-flight (TOF) spectrometer for measurement of the 2.5-MeV neutron emission from fusion plasmas has been developed and put into use at the JET tokamak. It has been optimized for operation at high rates (TOFOR) for the purpose of performing advanced neutron emission spectroscopy (NES) diagnosis of deuterium plasmas with a focus on the fuel ion motional states for different auxiliary heating scenarios. This requires operation over a large dynamic range, including high rates of > 100 kHz with a maximum value of 0.5 MHz for the TOFOR design. This paper describes the design principles and their technical realization. The performance is illustrated with recent neutron TOF spectra recorded for plasmas subjected to different heating scenarios. A true event count rate of 39 kHz has been achieved at about a tenth of the expected neutron yield limit of JET, giving a projected maximum of 400 kHz at peak JET plasma yield. This means that the count rate capability for NES diagnosis of D plasmas has been improved more than an order of magnitude. Another important performance factor is the spectrometer bandwidth, where data have been acquired and analyzed successfully with a response function for neutrons over the energy range 1 to > 5 MeV. The implications of instrumental advancement represented by TOFOR are discussed.

  • 23.
    Gatu Johnson, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, Luca
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, Emanuele
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    The TOFOR neutron spectrometer and its first use at JET2006In: Review of Scientific Instruments: Proceedings of the 16th topical conference on High-Temperature Plasma Diagnostics 7-11 May 2006 Williamsburg, Virginia, 2006, p. 840-Conference paper (Refereed)
    Abstract [en]

    A time-of-flight neutron spectrometer (TOFOR) has been developed to measure the 2.45 MeV d+d3He+n neutron emission from D plasmas. The TOFOR design features the capability to operate at high rates in the 100 kHz range, data collection with fast time digitizing and storing, and monitoring of the signals from the scintillation detectors used. This article describes the principles of the instrument and its installation at JET and presents preliminary data to illustrate the TOFOR performance as a neutron emission spectroscopy diagnostic.

  • 24. Giacomelli, L
    et al.
    Andersson Sunden, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    Murari, A
    Popovichev, S
    Souse, J
    Pereira, R.C
    Combo, A
    Cruz, N
    JET EFDA contributors,
    Development and characterization of the proton recoil detector for the MPRu neutron spectrometer2006In: Rev. Sci. Instrum, Vol. 77, p. 10E708-Article in journal (Refereed)
  • 25.
    Giacomelli, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Glasser, W
    Gorini, G
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Characterization of Phoswich Scintillation Detectors for the Focal Plane Hodoscope of Magnetic Proton Recoil Spectrometers for Fusion Neutrons2007Report (Other (popular scientific, debate etc.))
  • 26.
    Giacomelli, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sharapov, S
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Tardocchi, M
    Popovichev, S
    Johnson, T
    Neutron Emission Spectroscopy Diagnosis of Fast Ions in RF (3He) Heated Plasmas at JET2007Report (Other (popular scientific, debate etc.))
  • 27.
    Giacomelli, L
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Goroni, G
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Van Eester, D
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lerche, E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Johnson, T
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kiptily, V
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Neutron Emission Spectroscopy Results for ITB and Mode Conversion ICRH Experiments at JET2008In: Rev. Sci. Instr., submitted, 2008Conference paper (Refereed)
  • 28.
    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.

  • 29.
    Giacomelli, Luca
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, Giuseppe
    Henriksson, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, Marco
    Comparison of neutron emission spectra for D and DT plasmas with auxiliary heating2005In: The European Physical Journal D, no 33, p. 235-241Article in journal (Refereed)
    Abstract [en]

    The DT experimental campaign on JET (1997) represents a major step forward for neutron

    emission spectroscopy (NES) diagnostic through the high quality data collected by the Magnetic Proton

    Recoil (MPR) spectrometer. These data for different DT plasma heating scenarios were analyzed here to

    determine the underlying fuel ion populations which in turn were used to project the 2.5-MeV neutron

    emission spectra for deuterium plasmas. The results on neutron spectra for DT and D plasmas in the

    same conditions were compared in order to determine the plasma information that could be expected

    from NES diagnosis of D plasmas and the instrumental characteristics that would be required. Future

    NES experiments would make dual sight line observations possible and the added diagnostic value is also

    assessed based on the present results.

  • 30.
    Giacomelli, Luca
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Henriksson, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, Marco
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Glasser, Wolfgang
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, Giuseppe
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Johansson, Morgan
    Källne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Murari, Andrea
    Popovichev, Sergei
    Neutron emission spectroscopy of fuel ion rotation and fusion power components demonstrated in the trace tritium experiments at JET2004In: 31st EPS conference on Plasma Physics, 2004, p. P-5.171Conference paper (Other scientific)
  • 31.
    Giacomelli, Luca
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Glasser, Wolfgang
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G
    Henriksson, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Popovichev, S
    Ronchi, Emanuele
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Sousa, J
    Andersson Sundén, Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Thun, Johan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Advanced Neutron Diagnostics for JET and ITER Fusion Experiments2005In: Nuclear Fusion, Vol. 45, p. 1191-1201Article in journal (Refereed)
    Abstract [en]

    The diagnostics functions of neutron measurements as well as the roles played by neutron yield monitors, cameras and spectrometers are reviewed. The importance of recent developments in neutron emission spectroscopy (NES) diagnostics is emphasized. Results are presented from the NES diagnosis of the Joint European Torus (JET) plasmas performed with the magnetic proton recoil (MPR) spectrometer during the first deuterium tritium experiment of 1997 and the recent trace tritium experiment of 2003. The NES diagnostic capabilities at JET are presently being enhanced by an upgrade of the MPR (MPRu) and a new 2.5 MeV time-of-flight (TOF) neutron spectrometer (TOFOR). The principles of MPRu and TOFOR are described and illustrated with the diagnostic role they will play in the high performance fusion experiments in the forward programme of JET largely aimed at supporting the International Thermonuclear Experimental Reactor (ITER). The importance of the JET NES effort for ITER is discussed.

  • 32. Gorini, G
    et al.
    Andersson Sundén, E
    Uppsala University.
    Ballabio, L
    Conroy, S
    Uppsala University.
    Ericsson, G
    Uppsala University.
    Gatu Johnson, M
    Uppsala University.
    Giacomelli, L
    Uppsala University.
    Hellesen, C
    Uppsala University.
    Hjalmarsson, A
    Uppsala University.
    Källne, J
    Uppsala University.
    Murari, A
    Ognissanto, F
    Sjöstrand, H
    Uppsala University.
    Ronchi, E
    Uppsala University.
    Tardocchi, M
    Weiszflog, M
    Uppsala University.
    High-Energy Fuel Ion Diagnostics on ITER Derived from Neutron Emission Spectroscopy Measurements on JET DT Plasmas2006Report (Other (popular scientific, debate etc.))
  • 33. Gorini, G
    et al.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Henriksson, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Projected Neutron Spectroscopy Diagnostics of JET Deuterium Plasmas2001In: ADVANCED DIAGNOSTICS FOR MAGNETIC AND INERTIAL FUSION, 2001Conference paper (Other scientific)
  • 34. Gorini, G
    et al.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, Luca
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Henriksson, Hans
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, M
    Proposed Neutron Emission Spectroscopy Diagnostics of Energetic Deutrons in JET rium Plasmas2001In: 7th IAEA TCM on Energetic Particles, 2001Conference paper (Other scientific)
    Abstract [en]

    The DT experimental campaign on JET (1997) represented a major step forward for neutron emission

    spectroscopy (NES) diagnostics thanks to the high count rate measurements obtained with the

    magnetic proton recoil (MPR) neutron spectrometer in high fusion yield plasmas [1]. NES

    measurements were made on JET DT plasmas for different heating conditions including those

    generating energetic deuterons either directly through NB injection, or through ICRH acceleration

    using the (D)T minority scheme [2]. A multiple-component model has been developed for analysis

    of dt neutron spectra that is based on a simplified description of fuel ion velocity distributions for

    different heating conditions [3,4]. The same model is used here for projections of NES spectra from

    JET deuterium plasmas using the dt results as input. This is done on the basis of a system of two

    complementary NES instruments, the TOFOR (Time of Flight - Optimized Rate) [5] and MPRu

    (Magnetic Proton Recoil Upgrade) spectrometers that are presently proposed for installation on

    JET [6]. Both spectrometers would record neutron spectra in D plasmas but for different viewing

    lines. TOFOR would have a “vertical” view, i.e. at an angle of 90° relative to the toroidal magnetic

    field. This is the same viewing line used for some of the previous dd NES measurements on JET

    [7]. MPRu would have a “tangential” view, i.e. horizontal (on the equatorial plane) at an angle of

    47° relative to the toroidal magnetic field and opposite to the beam injection direction. This is the

    same viewing line used for the 1997 dt measurements using the magnetic proton recoil (MPR)

    spectrometer.

    Projections of dd neutron spectra under the assumptions above are used here for an assessment

    of the performance and requirements of NES as a diagnostic of energetic deuterons in JET.

  • 35.
    Gorini, Giuseppe
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, Jan
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Voitsekhovitch, I
    Adams, M
    Bertalot, L
    Budny, R
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, Luca
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hawkes, N
    Henriksson, Hans
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Joffrin, E
    Popovichev, S
    Sjöstrand, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Tardocchi, Marco
    de Vries, P
    Weiszflog, Matthias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Yavorskij, Y
    Zastrow, K-D
    Neutron Emission from Beam-Injected Fast Tritons in JET Plasmas with Reversed or Monotonic Magnetic Shear.2004In: 31st EPS Conference on Plasma Physics, 2004, p. 4-Conference paper (Other scientific)
    Abstract [en]

    The neutron emission from fast tritons in plasmas with different magnetic shear

    configurations has been investigated in a dedicated experiment on JET. Short pulses of

    neutral beam injection were used to deposit fast tritons in deuterium plasmas. By comparing

    the measured neutron yield with predictions based on DT reaction calculations, fast triton

    losses can be assessed. The latter are expected to be very low according to neoclassical

    predictions based on Fokker-Planck simulation [1]. Much larger “anomalous” beam-ion

    losses (up to 40%) have been reported in TFTR experiments for plasma conditions with

    reversed magnetic shear [2]. The TFTR experiments indicated an excess DT rate in the

    simulation and, to a lesser extent, in the DD rate and plasma stored energy. This was

    interpreted as anomalous beam-ion loss associated with reverse shear due to an unidentified

    loss mechanism. Evidence of a similar effect was searched for in the JET experiments

    reported in this paper.

  • 36. Hatano, Y.
    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
    Tritium distributions on W-coated divertor tiles used in the third JET ITER-like wall campaign2019In: Nuclear Materials and Energy, E-ISSN 2352-1791, Vol. 18, p. 258-261Article in journal (Refereed)
    Abstract [en]

    Tritium (T) distributions on tungsten (W)-coated plasma-facing tiles used in the third ITER-like wall campaign (2015-2016) of the Joint European Torus (JET) were examined by means of an imaging plate technique and beta-ray induced x-ray spectrometry, and they were compared with the distributions after the second (2013-2014) campaign. Strong enrichment of T in beryllium (Be) deposition layers was observed after the second campaign. In contrast, T distributions after the third campaign was more uniform though Be deposition layers were visually recognized. The one of the possible explanations is enhanced desorption of T from Be deposition layers due to higher tile temperatures caused by higher energy input in the third campaign.

  • 37.
    Hellesen, C
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gatu Johnson, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ronchi, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Albergante, M
    Gorini, G
    Tardocchi, M
    Jenkins, I
    Popovichev, S
    Measurements and Analysis of TOFOR Neutron Spectra from RF and NB Heated JET D plasmas2007Report (Other (popular scientific, debate etc.))
  • 38.
    Hellesen, Carl
    et al.
    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.
    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.
    Hjalmarsson, Anders
    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.
    Marcinkevicius, Benjaminas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conceptual design of a BackTOF neutron spectrometer for fuel ion ratio measurements at ITER2017In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 57, no 6, article id 066021Article in journal (Refereed)
    Abstract [en]

    In this paper we present a conceptual design of a back scattering neutron time of flight spectrometer (BackTOF) for use at ITER. The proposed BackTOF design aims at fulfilling the requirements set on a neutron spectrometer system to be used for inferring the core fuel ion ratio in a DT plasma. Specifically we have investigated the requirements on the size, energy resolution, count rate capability, efficiency and signal to background ratio. These requirements are a compact size that fits in roughly 1 m3, an energy resolution of 4% or better, a count rate capability of at least 100 kHz, an efficiency of at least 10−5 and a signal to background ratio of 1000 or better.

    Using a Monte Carlo model of the BackTOF spectrometer we find that the proposed BackTOF design is compact enough to be installed at ITER while being capable of achieving a resolution of about 4% FWHM with a count rate capability of 300 kHz and an efficiency at 1.25 10−3. This is sufficient for achieving the requirements on the fuel ion ratio at ITER. We also demonstrate how data acquisition systems capable of providing both timing and energy information can be used to effectively discriminate random background at high count rates.

  • 39.
    Hellesen, Carl
    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.
    Binda, Federico
    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.
    Hjalmarsson, Anders
    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.
    Fuel ion ratio determination in NBI heated deuterium tritium fusion plasmas at JET using neutron emission spectrometry2015In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 2, article id 023005Article in journal (Refereed)
    Abstract [en]

    The fuel ion ratio ( n t / n d ) is of central importance for the performance and control of a future burning fusion plasma, and reliable measurements of this quantity are essential for ITER. This paper demonstrates a method to derive the core fuel ion ratio by comparing the thermonuclear and beam-thermal neutron emission intensities, using a neutron spectrometer. The method is applied to NBI heated deuterium tritium (DT) plasmas at JET, using data from the magnetic proton recoil spectrometer. The trend in the results is consistent with Penning trap measurements of the fuel ion ratio at the edge of the plasma, but there is a discrepancy in the absolute values, possibly owing to the fact that the two measurements are weighted towards different parts of the plasma. It is suggested to further validate this method by comparing it to the traditionally proposed method to estimate n t / n d from the ratio of the thermal DD and DT neutron emission components. The spectrometer requirements for measuring n t / n d at ITER are also briefly discussed.

  • 40.
    Hellesen, Carl
    et al.
    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.
    Dzysiuk, N.
    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.
    Hjalmarsson, Anders
    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.
    Sundén, Erik Andersson
    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.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prospects for measuring the fuel ion ratio in burning ITER plasmas using a DT neutron emission spectrometer2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 11, p. 11D825-Article in journal (Refereed)
    Abstract [en]

    The fuel ion ratio n(t)/n(d) is an essential parameter for plasma control in fusion reactor relevant applications, since maximum fusion power is attained when equal amounts of tritium (T) and deuterium (D) are present in the plasma, i.e., n(t)/n(d) = 1.0. For neutral beam heated plasmas, this parameter can be measured using a single neutron spectrometer, as has been shown for tritium concentrations up to 90%, using data obtained with the MPR (Magnetic Proton Recoil) spectrometer during a DT experimental campaign at the Joint European Torus in 1997. In this paper, we evaluate the demands that a DT spectrometer has to fulfill to be able to determine n(t)/n(d) with a relative error below 20%, as is required for such measurements at ITER. The assessment shows that a back-scattering time-of-flight design is a promising concept for spectroscopy of 14 MeV DT emission neutrons.

  • 41.
    Henriksson, Hans
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Goran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, Luca
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Kallne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Systematic spectral features in the neutron emission from NB heated JET DT plasmas2005In: Plasma Physics and Controlled Fusion, Vol. 47, no 10, p. 1763-1785Article in journal (Refereed)
  • 42.
    Henriksson, Hans
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Goran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Kallne, Jan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    et al,
    Synergetic RF and NB heating effects in JET DT plasmas studied with neutron emission spectroscopy2006In: Nuclear Fusion, Vol. 46, no 2, p. 244-253Article in journal (Refereed)
  • 43.
    Jacobsen, A. S.
    et al.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Max Planck Inst Plasma Phys, Garching, Germany..
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Cazzaniga, C.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Sci & Technol Facil Council, Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England..
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.
    Nocente, M.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Salewski, M.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Tech Univ Denmark, Dept Phys, Kongens Lyngby, Denmark..
    Tardini, G.
    Culham Sci Ctr, EUROfus Consortium, JET, Abingdon OX14 3DB, Oxon, England.;Max Planck Inst Plasma Phys, Garching, Germany..
    Velocity-space sensitivities of neutron emission spectrometers at the tokamaks JET and ASDEX Upgrade in deuterium plasmas2017In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 88, no 7, article id 073506Article in journal (Refereed)
    Abstract [en]

    Future fusion reactors are foreseen to be heated by the energetic alpha particles produced in fusion reactions. For this to happen, it is important that the energetic ions are sufficiently confined. In present day fusion experiments, energetic ions are primarily produced using external heating systems such as neutral beam injection and ion cyclotron resonance heating. In order to diagnose these fast ions, several different fast-ion diagnostics have been developed and implemented in the various experiments around the world. The velocity-space sensitivities of fast-ion diagnostics are given by so-called weight functions. Here instrument-specific weight functions are derived for neutron emission spectrometry detectors at the tokamaks JET and ASDEX Upgrade for the 2.45 MeV neutrons produced in deuterium-deuterium reactions in deuterium plasmas. Using these, it is possible to directly determine which part of velocity space each detector observes.

  • 44. Jacobsen, A. S.
    et al.
    Salewski, M.
    Eriksson, Jacob
    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.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Korsholm, S. B.
    Leipold, F.
    Nielsen, S. K.
    Rasmussen, J.
    Stejner, M.
    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 11, p. 11E103-Article in journal (Refereed)
    Abstract [en]

    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutronemission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of ameasured time-of-flight spectrum from TOFOR.

  • 45.
    Jansson, Kaj
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Al-Adili, Ali
    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.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prokofiev, Alexander V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, The Svedberg Laboratory.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Designing an upgrade of the Medley setup for light-ion production and fission cross-section measurements2015In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 794, p. 141-150Article in journal (Refereed)
    Abstract [en]

    Abstract Measurements of neutron-induced fission cross-sections and light-ion production are planned in the energy range 1-40 MeV at the upcoming Neutrons For Science (NFS) facility. In order to prepare our detector setup for the neutron beam with continuous energy spectrum, a simulation software was written using the Geant4 toolkit for both measurement situations. The neutron energy range around 20 MeV is troublesome when it comes to the cross-sections used by Geant4 since data-driven cross-sections are only available below 20 MeV but not above, where they are based on semi-empirical models. Several customisations were made to the standard classes in Geant4 in order to produce consistent results over the whole simulated energy range. Expected uncertainties are reported for both types of measurements. The simulations have shown that a simultaneous precision measurement of the three standard cross-sections H(n,n), 235U(n,f) and 238U(n,f) relative to each other is feasible using a triple layered target. As high resolution timing detectors for fission fragments we plan to use Parallel Plate Avalanche Counters (PPACs). The simulation results have put some restrictions on the design of these detectors as well as on the target design. This study suggests a fissile target no thicker than 2 µm (1.7 mg/cm2) and a PPAC foil thickness preferably less than 1 µm . We also comment on the usability of Geant4 for simulation studies of neutron reactions in this energy range.

  • 46. Joffrin, E.
    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.
    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.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sahlberg, Arne
    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
    Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall2019In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 59, no 11, article id 112021Article in journal (Refereed)
    Abstract [en]

    For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.

  • 47.
    Kazakov, Ye. O.
    et al.
    TEC Partner, Lab Plasma Phys, LPP ERM KMS, B-1000 Brussels, Belgium.
    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, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Weiszflog, Matthias
    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.
    Binda, F.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    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.
    Kazantzidis, V.
    Natl Tech Univ Athens, Iroon Politechniou 9, Zografos 15773, Greece.
    Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating2017In: Nature Physics, ISSN 1745-2473, E-ISSN 1745-2481, Vol. 13, no 10, p. 973-978Article in journal (Refereed)
    Abstract [en]

    We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed three-ion scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of He-3 ions to high energies in dedicated hydrogendeuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast He-3 ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, He-3-rich solar flares.

  • 48.
    Krasilnikov, A.V
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    van Eester, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lerche, E
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ongena, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mailloux, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stamp, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jachmich, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Leggate, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Vdoniv, V
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Walden, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mayoral, M.L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Bonheure, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Santala, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kiptily, V
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Popovichev, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Biewer, T
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Crombe, K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Esposito, B
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Marocco, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Riva, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kaschuck, Yu.A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Amosov, V.N
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, G
    Department of Neutron Research. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Isobe, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nishiura, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sasao, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nichimura, H
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Saito, K
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Seki, T
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mutoh, T
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kumazawa, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Takeiri, Y
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Osakabe, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Goto, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Murakami, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Goncharov, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency2007In: AIP Conference Proceedings 933, 2007, p. 43-Conference paper (Other (popular scientific, debate etc.))
  • 49. Krasilnikov, A.V
    et al.
    Van Eester, D
    Lerche, E
    Ongena, J
    Mailloux, J
    Stamp, M
    Jachmich, S
    Leggate, H
    Vdovin, V
    Walden, A
    Mayoral, M.-L
    Bonheure, G
    Santala, M
    Kiptily, V
    Popovichev, S
    Biewer, T
    Crombe, K
    Esposito, B
    Marocco, D
    Riva, M
    Kaschuck, Yu.A
    Amosov, V.N
    Ericsson, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research. Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, A
    Department of Physics and Astronomy, Applied Nuclear Physics.
    Källne, J
    Department of Physics and Astronomy, Applied Nuclear Physics.
    ICRH of JET and LHD Majority Ions at their Fundamental Cyclotron Frequency2007Report (Other (popular scientific, debate etc.))
  • 50.
    Lawson, K. D.
    et al.
    UKAEA/CCFE, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom.
    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, PL-05400 Otwock, Poland.
    Population modelling of the He II energy levels in tokamak plasmas: I. Collisional excitation model2019In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 52, no 4, article id 045001Article in journal (Refereed)
    Abstract [en]

    Helium is widely used as a fuel or minority gas in laboratory fusion experiments, and will be present as ash in DT thermonuclear plasmas. It is therefore essential to have a good understanding of its atomic physics. To this end He II population modelling has been undertaken for the spectroscopic levels arising from shells with principal quantum number n = 1-5. This paper focuses on a collisional excitation model; ionisation and recombination will be considered in a subsequent article. Heavy particle collisional excitation rate coefficients have been generated to supplement the currently-available atomic data for He II, and are presented for proton, deuteron, triton and alpha-particle projectiles. The widely-used criterion for levels within an n shell being populated in proportion to their statistical weights is reassessed with the most recent atomic data, and found not to apply to the He II levels at tokamak densities (10(18)-10(21) m(-3)). Consequences of this and other likely sources of errors are quantified, as is the effect of differing electron and ion temperatures. Line intensity ratios, including the so-called 'branching ratios' and the fine-structure beta(1), beta(2), beta(3), and gamma ratios, are discussed, the latter with regard to their possible use as diagnostics.

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