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  • 1. Billnert, R.
    et al.
    Oberstedt, S.
    Andreotti, E.
    Hult, M.
    Marissens, G.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    New information on the characteristics of 1 in. x 1 in. cerium bromide scintillation detectors2011In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 647, no 1, p. 94-99Article in journal (Refereed)
    Abstract [en]

    In view of highly demanded new and accurate data on prompt gamma-ray emission in nuclear fission a major part of investigations is directed towards the selection of suitable detector systems. Here we have studied a new type of crystal scintillation detectors made from cerium bromide (CeBr(3)). For the first time a full characterization of such a detector is presented in terms of energy resolution, pulse-height linearity, intrinsic activity and intrinsic timing resolution. In particular the latter one is very important for prompt fission gamma-ray studies, because the presence of fast neutrons, emitted in fission too, requires the time-of-flight method for their discrimination. The energy resolution has been found to be comparable to that of cerium-doped LaCl(3):Ce detectors at an efficiency comparable to the one of a LaBr(3):Ce detector of the same size. The intrinsic activity of the CeBr(3) crystal was observed to be much lower compared to lanthanum halide crystals. The intrinsic timing resolution of a coaxial 1 in. x 1 in. sized detector was measured relative to that of a previously characterized LaCl(3):Ce detector and found to be (326 +/- 7) Ps at (60)Co energies, which is in between those of a LaBr(3):Ce and a LaCl(3):Ce detector of same size. (C) 2011 Elsevier B.V. All rights reserved.

  • 2.
    Birgersson, Evert
    et al.
    Örebro University, School of Science and Technology.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Oberstedt, Stephan
    Hambsch, Franz-Josef
    Properties of the reaction 238U(n, f) at the vibrational resonances2009In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 817, no 1-4, p. 1-34Article in journal (Refereed)
    Abstract [en]

    Recent fission cross-section calculations for the reaction 238U(n, f ), based on an extended statistical model, predict a significant change of fission fragment properties, such as the mean mass by A = 1.5 and a notable increase in total kinetic energy in the region of the vibrational resonance at an incident neutron energy En = 0.9 MeV. This model includes individual fission cross-sections by the asymmetric standard 1 (S1) and standard 2 (S2) as well as the symmetric super-long (SL) mode. In order to verify the model predictions, a dedicated experiment on 238U has been carried out to measure fission-fragment mass yield distributions for incident neutron energies from En = 2.0 MeV down to 0.9 MeV, where the fission characteristics at the vibrational resonance at En = 0.9 MeV were investigated for the first time. The previously reported distinct structure in the angular anisotropy around En = 1.2 and 1.6 MeV wasobserved at En = 0.9 MeV as well. The predicted large changes in fission fragment mass yield and total kinetic energy could not be confirmed. In the resonance the mean total kinetic energy is only about 0.5 MeV higher than at En = 1.8 MeV. At the same time, a slight decrease of the mean heavy fragment mass was observed, probably indicating a slightly increased contribution of the S1 fission mode.

  • 3.
    Birgersson, Evert
    et al.
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Rochman, Dimitri
    Tsekhanovich, Igor
    Raman, Subramanian
    Light fission-fragment mass distribution from the reaction 251Cf(nth, f)2007In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 791, no 1-2, p. 1-23Article in journal (Refereed)
    Abstract [en]

    For mass numbers A = 80 to 124 the recoil mass spectrometer LOHENGRIN of the Institute Laue-Langevin in Grenoble was used to measure with high resolution the light fission-fragment mass yields and kinetic energy distributions from thermal-neutron induced fission of 252Cf* for the first time, using 251Cf as target material. The obtained mean light fragment mass AL = (107 ± 2) and the corresponding mean kinetic energy Ek,L = (103±2) MeV are within the expected trend. Emission yields around A = 115 are enhanced and the corresponding mean kinetic energy is higher compared to spontaneous fission of 252Cf. This could be explained by the existence of an additional super-deformed fission mode.

  • 4.
    Birgersson, Evert
    et al.
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Rochman, Dimitri
    Tsekhanovitsch, Igor
    Binary fission-fragment yields from the reaction 251Cf(nth, f)2005In: Nuclear fission and fission-product spectroscopy: 3rd international workshop on nuclear fission and fission-product spectroscopy, American Institute of Physics , 2005, p. 349-352Conference paper (Refereed)
    Abstract [en]

    The recoil mass spectrometer LOHENGRIN of the Laue-Langevin Institute, Grenoble has been used to measure the light fission-fragment mass yield and kinetic energy distributions from neutron-induced 252Cf*, using 251Cf as target material. ©2005 American Institute of Physics

  • 5. Göök, A.
    et al.
    Barday, R.
    Chernykh, M.
    Eckardt, C.
    Eichhorn, R.
    Enders, J.
    Hambsch, F. -J
    Von Neumann-Cosef, P.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Oberstedt, S.
    Poltoratska, Y.
    Richter, A.
    Wagner, M.
    Photo-fission at the S-DALINAC2009In: 4th international workshop on nuclear fission and fission-product spectroscopy / [ed] Audrey Chatillon ..., American Institute of Physics (AIP), 2009, Vol. 1175, p. 351-354Conference paper (Other academic)
    Abstract [en]

    Experiments on photo-induced fission of 238U and 234U using bremsstrahlung with endpoint energies between 6 MeV and 9 MeV have been carried out at the superconducting Darmstadt electron linear accelerator S-DALINAC. A twin Frisch grid ionization chamber has been used to determine energy and mass distributions via the 2E-technique. The fission fragment emission angle, which is used to correct for energy loss in the target and backing material for a correct determination of fragment energy and mass, is deduced from the time difference between cathode and anode signals. The research program including the foreseen search for parity violation in photo-induced fission and first experimental results will be presented. © 2009 American Institute of Physics.

  • 6.
    Göök, A.
    et al.
    Örebro University, School of Science and Technology.
    Chernykh, M.
    Eckardt, C.
    Enders, J.
    von Neumann-Cosel, P.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Oberstedt, S.
    Richter, A.
    Fragment characteristics from fission of (238)U and (234)U induced by 6.5-9.0 MeV bremsstrahlung2011In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 851, no 1, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Fission of (238)U and (234)U induced by bremsstrahlung of 6.5-9.0 MeV endpoint energy has been investigated at the superconducting Darmstadt electron linear accelerator S-DALINAC. Using a twin Frisch grid ionization chamber, fission-fragment energy and mass distributions have been determined by means of the double kinetic-energy technique. Results on the fission-fragment characteristics from (238)U(gamma, f) are in agreement with results from the literature. In addition fission-fragment mass and energy distributions from (234)U(gamma, f) are presented for the first time in this energy region. An analysis of fission modes within the Brosa model has been performed. The relative yield of the S 1 mode was found to be (13 +/- 3)% in (234)U and (35 +/- 2)% in (238)U. (C) 2010 Elsevier B.V. All rights reserved.

  • 7.
    Göök, A.
    et al.
    Inst Kernphys, Tech Univ Darmstadt, Darmstadt, Germany; Akademin för Naturvetenskap och Teknik, Örebro Universitet, Örebro, Sweden.
    Chernykh, M.
    Inst Kernphys, Tech Univ Darmstadt, Darmstadt, Germany.
    Enders, J.
    Inst Kernphys, Tech Univ Darmstadt, Darmstadt, Germany.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Oberstedt, S.
    Inst Reference Mat & Measurements IRMM, EU Science Hub Joint Research Centre (JRC), Geel, Belgium.
    Particle emission angle determination in Frisch grid ionization chambers by electron drift-time measurements2010In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 621, no 1-3, p. 401-405Article in journal (Refereed)
    Abstract [en]

    The double kinetic energy measurement of fission fragments with a double-sided Frisch grid ionization chamber allows a careful determination of the emission angle, which is essential in order to apply appropriate energy-loss corrections. We present a drift-time method, which uses the time that free electrons need to drift from the location of their creation, e.g. by a fission fragment in the counting gas, to the grid, before inducing a signal on the anode. Such a measurement leaves energy and angular information fully decoupled. We demonstrate the applicability of the drift-time method for the example of the U-234,U-238 (gamma,f) reactions performed at the superconducting Darmstadt electron linear accelerator. The angular resolutions achieved with this method are comparable to those obtained with other methods. (C) 2010 Elsevier B.V. All rights reserved.

  • 8.
    Göök, A.
    et al.
    Technische Universität Darmstadt, Darmstadt, Germany.
    Hambsch, F. -J
    EC-JRC Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology. Chalmers Tekniska Högskola, Göteborg, Sweden.
    Oberstedt, S.
    EC-JRC Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Application of the Shockley-Ramo theorem on the grid inefficiency of Frisch grid ionization chambers2012In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 664, no 1, p. 289-293Article in journal (Refereed)
    Abstract [en]

    The concept of grid inefficiency in Frisch grid ionization chambers and its influence on the anode pulse shape is explained in terms of the Shockley-Ramo theorem for induced charges. The grid inefficiency correction is deduced from numerically calculated weighting potentials. A method to determine the correction factor experimentally is also presented. Experimental and calculated values of the correction factor are shown to be in good agreement.

  • 9. Hambsch, F. -J
    et al.
    Oberstedt, S.
    Al-Adil, A.
    Borcea, R.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Tudora, A.
    Zeynalov, Sh.
    Investigation of the Fission Process at IRMM2011In: Journal of the Korean Physical Society, ISSN 0374-4884, E-ISSN 1976-8524, Vol. 59, no 2, p. 1654-1659Article in journal (Refereed)
    Abstract [en]

    The investigation of the fission process is and has been a major undertaking at IRMM. The most recent investigations concerned the reaction (234)U(n,f) and (238)U(n,f) around vibrational resonances at the barrier of the fission cross-section. Furthermore prompt neutron emission of (252)Cf(SF) has been investigated understanding for the first time the prompt neutron multiplicity as a function of total kinetic energy (TKE). Theoretical modelling of reaction cross sections as well as prompt neutron multiplicity and spectra has been performed using the experimental data as input parameters. Also instrument developments for correlation measurements of fission fragment properties has been pursued in recent years with the time-of-flight spectrometer VERDI and detectors for prompt fission gamma-ray.

  • 10.
    Hambsch, F. -J
    et al.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Oberstedt, S.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Al-Adili, A.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Division of Applied Nuclear Physics, Uppsala University, Uppsala, Sweden.
    Brys, T.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Billnert, R.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Fundamental Physics, Chalmers University of Technology, Göteborg, Sweden.
    Matei, C.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium;National Physical Laboratory, Teddington, United Kingdom.
    Oberstedt, Andreas
    School of Science and Technology, Örebro University, Örebro, Sweden.
    Salvador-Castineira, P.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Institute of Energy Technologies, Technical University of Catalonia, Córdoba, Spain.
    Tudora, A.
    Faculty of Physics, University of Bucharest, Bucharest-Magurele, Romania.
    Vidali, M.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Fission Fragment Yield, Cross Section and Prompt Neutron and Gamma Emission Data from Actinide Isotopes2014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. E38-E41Article in journal (Refereed)
    Abstract [en]

    Recent experimental investigations on major and minor actinides at the JRC-IRMM are presented. Fission-fragment distributions of isotopes with vibrational resonances in the sub-threshold fission cross section, i. e. U-234,U-238, have been measured. For U-234, the impact of an increased neutron multiplicity for the heavy fragments with higher incident neutron energies has been studied as observed in experiment and also recently theoretically predicted. The impact is found to be noticeable on post-neutron mass yields, which are the relevant quantities for a-priori waste assessments. The fission cross sections for Pu-240,Pu-242 at threshold and in the plateau region are being investigated within the ANDES project. The results show some discrepancies to the ENDF/B-VII. 1 evaluation mainly for Pu-242 around 1 MeV, where the evaluation exhibits a resonance-like structure not observed so clearly in the present work. The requested target accuracy in design studies of innovative reactor concepts like Gen-IV is in the range of a few percent. In order to be able to respond to requests for measurements of prompt neutron and gamma-ray emission in fission JRC-IRMM has also invested in setting up a neutron and gamma-ray detector array. The neutron array is called SCINTIA and has so far been tested with Cf-252(SF). For gamma-ray multiplicity and spectrum measurements of Cf-252(SF) and U-235(n(th), f) lanthanum- and cerium-halide detectors were successfully used.

  • 11.
    Ledoux, X.
    et al.
    The Commissariat à l'énergie atomique et aux énergies alternatives/Direction des applications militaires/DAM Ile-de-France (CEA/DAM/DIF), Arpajon, France.
    Aiche, M.
    Le Centre national de la recherche scientifique/Institut national de physique nucléaire et de physique des particules, Centre d'Etudes Nucléaires de Bordeaux-Gradignan, UMR5797, (CNRS/IN2P3, CENBG, UMR5797), Gradignan, France.
    Avrigeanu, M.
    Institutul National de Cercetare-Dezvoltare pentru Fizica si Inginerie Nucleara Horia Hulubei, Bucharest, Romania.
    Avrigeanu, V.
    Institutul National de Cercetare-Dezvoltare pentru Fizica si Inginerie Nucleara Horia Hulubei, Bucharest, Romania.
    Audouin, L.
    Le Centre national de la recherche scientifique/Institut national de physique nucléaire et de physique des particules-Institut de physique nucléaire (CNRS/IN2P3-IPN), Orsay, France.
    Oberstedt, Andreas
    Örebro university, Örebro, Sweden.
    Tarrio, D.
    Department of physics and astronomy, Uppsala University, Uppsala, Sweden.
    Takibayev, A.
    Commissariat à l'énergie atomique et aux énergies alternatives/Direction des Sciences de la Matière, Physical Sciences Division/Institut de recherche sur les lois fondamentales de l'univers/CEA Nuclear Physics Division (CEA/DSM/IRFU/SPhN), Saclay, France.
    Thfoin, I.
    The Commissariat à l'énergie atomique et aux énergies alternatives/Direction des applications militaires/DAM Ile-de-France (CEA/DAM/DIF), Arpajon, France.
    Tsekhanovich, I.
    Le Centre national de la recherche scientifique/Institut national de physique nucléaire et de physique des particules, Centre d'Etudes Nucléaires de Bordeaux-Gradignan, UMR5797, (CNRS/IN2P3, CENBG, UMR5797), Gradignan, France.
    Varignon, C.
    The Commissariat à l'énergie atomique et aux énergies alternatives/Direction des applications militaires/DAM Ile-de-France (CEA/DAM/DIF), Arpajon, France.
    The Neutrons for Science Facility at SPIRAL-22014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. E353-E356Article in journal (Refereed)
    Abstract [en]

    The Neutrons For Science (NFS) facility is a component of SPIRAL-2 laboratory under construction at Caen (France). SPIRAL-2 is dedicated to the production of high intensity Radioactive Ions Beams (RIB). It is based on a high-power linear accelerator (LINAG) to accelerate deuterons beams in order to produce neutrons by breakup reactions on a C converter. These neutrons will induce fission in U-238 for production of radioactive isotopes. Additionally to the RIB production, the proton and deuteron beams delivered by the accelerator will be used in the NFS facility. NFS is composed of a pulsed neutron beam and irradiation stations for cross-section measurements and material studies. The beams delivered by the LINAG will allow producing intense neutron beams in the 100 keV - 40 MeV energy range with either a continuous or quasi-mono-energetic spectrum. At NFS available average fluxes will be up to 2 orders of magnitude higher than those of other existing time-of-flight facilities in the 1 MeV - 40 MeV range. NFS will be a very powerful tool for fundamental physics and application related research in support of the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors. The facility and its characteristics are described, and several examples of the first potential experiments are presented.

  • 12.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology.
    Belgya, T.
    Billnert, R.
    Borcea, R.
    Brys, T.
    Geerts, W.
    Goeoek, A.
    Hambsch, F. -J
    Kis, Z.
    Martinez, T.
    Oberstedt, S.
    Szentmiklosi, L.
    Takacs, K.
    Vidali, M.
    Improved values for the characteristics of prompt-fission gamma-ray spectra from the reaction U-235(n(th), f)2013In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 87, no 5, p. 051602-Article in journal (Refereed)
    Abstract [en]

    In this paper we present results from measurements of prompt gamma rays from the thermal neutron induced fission of U-235. Photons were measured in coincidence with fission fragments with cerium-doped LaCl3 and LaBr3 as well as CeBr3 scintillation detectors, which offer an intriguing combination of excellent timing resolution and good resolving power. The spectra measured with all employed detectors are in excellent agreement with respect to their shapes. Characteristic parameters were extracted for a gamma-energy range from 0.1 to 6.0 MeV and the results obtained with several detectors were averaged. From that, the average emission yield of prompt-fission gamma rays was determined to be (nu) over bar (gamma) = (8.19 +/- 0.11) per fission, the average energy per photon to be epsilon(gamma) = (0.85 +/- 0.02) MeV, and the total energy to be E-gamma,E-tot = (6.92 +/- 0.09) MeV. The uncertainties are much lower than the 7.5% requested for the modeling of advanced nuclear reactor cores. Estimating the influence of gamma rays with energies between 6 and 10 MeV on the values determined in this work revealed a negligible deviation of the order of the found uncertainties.

  • 13.
    Oberstedt, Andreas
    et al.
    Akademin för Naturvetenskap och Teknik, Örebro Universitet, Örebro, Sweden; Fundamental Fysik, Chalmers Tekniska Högskola, Göteborg, Sweden.
    Belgya, T.
    KFKI Atomic Energy Research Institute, Budapest, Hungary.
    Billnert, R.
    Fundamental Fysik, Chalmers Tekniska Högskola, Göteborg, Sweden; European Commission, DG Joint Research Centre (IRMM), Geel, Belgium.
    Hambsch, F. -J
    European Commission, DG Joint Research Centre (IRMM), Geel, Belgium.
    Kis, Z.
    KFKI Atomic Energy Research Institute, Budapest, Hungary.
    Perez, T. Martinez
    Nuclear Innovation Group, Department of Energy, CIEMAT, Madrid, Spain.
    Oberstedt, S.
    European Commission, DG Joint Research Centre (IRMM), Geel, Belgium.
    Szentmiklosi, L.
    KFKI Atomic Energy Research Institute, Budapest, Hungary.
    Takacs, K.
    KFKI Atomic Energy Research Institute, Budapest, Hungary.
    Vidali, M.
    European Commission, DG Joint Research Centre (IRMM), Geel, Belgium.
    New prompt fission gamma-ray spectral data and its implication on present evaluated nuclear data files2013In: Physics Procedia, ISSN 1875-3892, E-ISSN 1875-3892, Vol. 47, p. 156-165Article in journal (Refereed)
    Abstract [en]

    In this paper we report on new spectral prompt gamma-ray measurements from the spontaneous fission of Cf-252 and thermal neutron-induced fission of U-236*. In both experiments, fission of U-236*. In both experiments, gamma-ray multiplicities, average and total gamma-energies were extracted. gamma-ray multiplicities, average and total.-energies were extracted. Apart from one recent measurement on Cf-252, about four decades have passed since the last dedicated experiments were reported in literature. Hence, there was a need for a revision, not only with respect to high priority nuclear data requests by the Nuclear Energy Agency (NEA). In the first mentioned experiment we have measured prompt fission gamma-rays with both cerium-doped LaBr3 and CeBr3 scintillation detectors, which both exhibit excellent timing and good energy resolution. The results from both detectors are in excellent agreement with each other and confirm the historical data. In the experiment on U-235(n(th), f) we employed cerium-doped LaCl3 detectors, together with the lanthanum bromide detectors mentioned above. Even here the first results indicate a good agreement with data from the early 1970' s. They are also in accordance with data in evaluated libraries like ENDF/B-VII.0, while this is not the case for Cf-252(SF). Hence, here an update is strongly recommended.

  • 14.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology.
    Billnert, R.
    Karlsson, J.
    Oberstedt, S.
    Geerts, W.
    Hambsch, F. -J
    Characterization of LaCl3:Ce detectors for prompt fission gamma-ray measurements2009In: 4th international workshop on nuclear fission and fission-product spectroscopy / [ed] Audrey Chatillon, American Institute of Physics (AIP), 2009, Vol. 1175, p. 257-260Conference paper (Other academic)
    Abstract [en]

    The properties of cylindrical 1.5//×1.5//LaCl3:Cescintillation detectors were determined. For the energy resolution values between 3.8 and 4.2% at 662 keV were observed, following the expected E-1/2 behavior. The intrinsic full peak efficiency was determined to be more than 50% higher than for NaI:Tl detectors of same size. The observed intrinsic timing resolution for 60Co was estimated to 441 ps and the intrinsic activity of the lanthanum crystals was assessed. © 2009 American Institute of Physics.

  • 15.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology.
    Billnert, R.
    Oberstedt, S.
    Neutron measurements with lanthanum-bromide scintillation detectors: a first approach2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 708, p. 7-14Article in journal (Refereed)
    Abstract [en]

    In this paper we report on the measurement of gamma-rays using a 2 in. x 2 in. LaBr3:Ce scintillation detector. The gamma-rays were emitted in the spontaneous fission of Cf-252 and detected in coincidence with fission fragments. After presenting some of the properties of the detector, we show how well gamma-rays produced in different reactions may easily be distinguished by their characteristic time-of-flight. Then we focus on the analysis of gamma-rays from inelastically scattered neutrons in the scintillation crystal and demonstrate how this information may be used for neutron spectroscopy. We determine the neutron detection efficiency and compare it to the result of calculations based on existing reaction cross-sections. Finally, we discuss the detection performance in relation to other detector systems commonly used for neutron monitoring.

  • 16.
    Oberstedt, Andreas
    et al.
    Örebro University, Department of Natural Sciences.
    Birgersson, Evert
    Örebro University, Department of Natural Sciences.
    Tovesson, Fredrik
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Oberstedt, Stephan
    Fritsch, Volker
    Vladuca, Gheorghita
    Tudora, Annabella
    Fogelberg, Birger
    Ramström, Elisabet
    Neutron reaction cross section data for advanced nuclear applications2005In: Proceedings of the 11th international topical meeting on nuclear reactor thermal-hydraulics (NURETH-11): 262, 2005, p. 1-9Conference paper (Refereed)
  • 17.
    Oberstedt, Andreas
    et al.
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Energy degrader technique for light-charged particle spectroscopy at LOHENGRIN2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 570, no 1, p. 51-54Article in journal (Refereed)
    Abstract [en]

    The recoil mass-separator LOHENGRIN at Institute Laue-Langevin was originally designed for the spectrometry of binary fission fragments. Nevertheless, it was also used in the past for measuring light-charged particles from ternary fission. However, due to the electric field settings the energy distribution of the lightest particles was not completely accessible, which made the determination of mean kinetic energies, widths and, hence, emission yields difficult. In this paper we present an energy degrader technique that allows for the measurement of the entire energy spectrum of even the lightest ternary particles with LOHENGRIN.

  • 18.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology. Chalmers Tekniska Högskola, Göteborg, Sweden.
    Oberstedt, Stephan
    EC-JRC Institute for Reference Materials and Measurements (IRMM) Geel, Belgium .
    Billnert, R.
    Akademi för Naturvetenskap och Teknik, Örebro Universitet, Örebro, Sweden; Chalmers Tekniska Högskola, Göteborg, Sweden; EC-JRC Institute for Reference Materials and Measurements (IRMM), Geel, Belgium .
    Geerts, W.
    EC-JRC Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Hambsch, F. -J.
    EC-JRC Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Karlsson, J.
    Akademi för Naturvetenskap och Teknik, Örebro Universitet, Örebro, Sweden.
    Identification of prompt fission gamma-rays with lanthanum-chloride scintillation detectors2012In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 668, p. 14-20Article in journal (Refereed)
    Abstract [en]

    In this paper we demonstrate the employment of LaCl3 : Ce scintillation detectors for the identification of prompt fission gamma-rays from gamma-radiation in contrast to other reactions. We present the properties of cylindrical 1.5 in. x 1.5 in. detectors in terms of intrinsic activity, energy resolution, intrinsic full peak efficiency and intrinsic timing resolution. In addition, we show results from the measurement of gamma-rays emitted in coincidence with the spontaneous fission of Cf-252, which lead us to the conclusion that the properties of the detectors used in this work, in particular the good timing resolution and a reasonably good energy resolution, are more than just sufficient for the assessment of prompt gamma-heat in future nuclear reactors as requested by the OECD. Hence, in our opinion, LaCl3 : Ce detectors, compared to those made out of LaBr3 : Ce crystals, represent an appropriate and quasi low-cost choice for the above mentioned applications.

  • 19.
    Oberstedt, Andreas
    et al.
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Birgersson, Evert
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Fritsch, Volker
    Lövestam, Göran
    Vladuca, Gheorghita
    Tudora, Annabella
    Kornilov, Nikolai
    Recent results on the neutron-induced fission cross-section of 231Pa2005In: Proceedings of the 3rd international workshop on nuclear fission and fission-product spectroscopy, American Institute of Physics , 2005, p. 27-30Conference paper (Refereed)
    Abstract [en]

    The cross-section for the neutron-induced fission of 231Pa has recently been measured from the threshold to En = 3.5 MeV. The experimental results are described in terms of extended statistical model calculations.

  • 20.
    Oberstedt, Andreas
    et al.
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Gawrys, Michael
    Kornilov, Nikolai
    Identification of a Shape Isomer in 235U2007In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, no 4, p. 1-4Article in journal (Refereed)
    Abstract [en]

    The shape isomer in 235U has been searched for in a neutron-induced fission experiment on 234U, which was performed at the isomer spectrometer NEPTUNE of the EC-JRC IRMM. A neutron source, with a tunable pulse frequency in the Hz to kHz range and its individually adjustable neutron pulse width in connection with an appropriate detector system turned out to be the ideal instrument to perform an isomer search, when decay half-lives above 100 us are expected. From the delayed fission events observed for two different NEPTUNE settings and at mean incident neutron energies En = 0.95 and 1.27 MeV the isomeric fission half-life could be determined to be T_1/2 = (3.6 ± 1.8) ms. The corresponding cross section was determined to sigma_if = (10 ± 8) ub. With these results an experimental confirmation for the existence of a superdeformed shape isomer in odd-uranium isotopes is given for the first time.

  • 21.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology.
    Oberstedt, Stephan
    Rochman, Dimitri
    Energy degrader technique for light-charged particle spectroscopy at LOHENGRIN2008In: Seminar on Fission VI, Corsendonk Priory, Belgium, September 18-21, 2007 / [ed] Cyriel Wagemans, Jan Wagemans, Pierre D'hondt, 2008, , p. 8p. 99-106Conference paper (Refereed)
    Abstract [en]

    Although the recoil mass-separator LOHENGRIN at Institute Laue-Langevin was originally designed for the spectrometry of binary fission fragments, it was also used in the past for measuring light-charged particles from ternary fission. However, due to limited electric field settings the energy distribution of the lightest particles was not completely accessible. In this contribution we report on an energy degrader technique that allows the measurement of the entire energy spectra of ternary particles with LOHENGRIN. We demonstrate how the measured particle spectra are distorted by the energy degrader and present results from a Monte Carlo simulation that shows how the original energy distributions are reconstructed. Finally, we apply this procedure to experimental data of ternary particles from the reaction 235U(nth, f).

  • 22.
    Oberstedt, Andreas
    et al.
    Örebro University, School of Science and Technology.
    Oberstedt, Stephan
    Rochman, Dimitri
    Energy degrader technique for light-charged particle spectroscopy at LOHENGRIN2008In: ND-2007 International Conference on Nuclear Data for Science and Technology, Nice, France, 2008, , p. 4p. 379-382Conference paper (Refereed)
    Abstract [en]

    The recoil mass-separator LOHENGRIN at Institute Laue-Langevin was originally designed for the spectrometry of binary fission fragments. Nevertheless, it was also used in the past for measuring light-charged particles from ternary fission. However, due to the electric field settings the energy distribution of the lightest particles was not completely accessible, which made the determination of mean kinetic energies, widths and, hence, emission yields difficult. In this paper we present an energy degrader technique that allows for the measurement of the entire energy spectrum of even the lightest ternary particles with LOHENGRIN.

  • 23.
    Oberstedt, S.
    et al.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Billnert, R.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Fundamental Fysik, Chalmers Tekniska Högskola, Göteborg, Sweden.
    Belgya, T.
    Centre of Energy, Institute for Energy Security and Environmental Safety (EKBI), Hungarian Academy of Science, Budapest, Hungary.
    Borcea, R.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Depart. Nucl. Phys., Horia Hulubei National Institute for Physics and Nuclear Engineering / Institutul National pentru Fizica si Inginerie Nucleara - Horia Hulubei (IFIN-HH), Bucharest-Magurele, Romania.
    Brys, T.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Geerts, W.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Göök, A.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Institut für Kernphysik, Technische Universität, Darmstadt, Germany.
    Hambsch, F. -J
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    Kish, Z.
    Institute of Isotopes, Hungarian Academy of Science, Budapest, Hungary.
    Martinez Perez, T.
    Nuclear Innovation Group, Department of Energy, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain.
    Oberstedt, Andreas
    Fundamental Fysik, Chalmers Tekniska Högskola, Göteborg, Sweden; Akademin för Naturvetenskap och Teknik, Örebro Universitet, Örebro, Sweden.
    Szentmiklosi, L.
    Institute of Isotopes, Hungarian Academy of Science, Budapest, Hungary.
    Vidali, M.
    European Commission, Joint Research Centre (JRC), Institute for Reference Materials and Measurements (IRMM), Geel, Belgium.
    New Prompt Fission gamma-ray Data in Response to the OECD/NEA High Priority Request2014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. E225-E228Article in journal (Refereed)
    Abstract [en]

    In this paper we report about new prompt fission gamma-ray measurements, which we have performed with highly efficient gamma-ray detectors based on lanthanide-halide crystals, aiming at very fast timing in conjunction with a good energy resolution. About four decades after the experiments were performed, whose results are still used for current evaluations, we present new spectral prompt fission gamma-ray data from the reactions Cf-252(SF) and U-235(n(th),f). Based on our new findings we recommend to replace the current ENDF/B-VII. 1 evaluation for Cf-252(SF) and U-235(n(th),f) as well as to perform new measurements for U-238(n,f) and Pu-241(n,f).

  • 24. Oberstedt, S.
    et al.
    Borcea, R.
    Brys, T.
    Gamboni, Th.
    Geerts, W.
    Hambsch, F. -J
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Vidali, M.
    Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 714, p. 31-37Article in journal (Refereed)
    Abstract [en]

    In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from Cf-252 (0.5 MeV/u < E/A < 2 MeV/u). Signal stability under a high radiation fluence was determined up to at least 10(9) fission-fragments/cm(2) together with more than 3.5 x 10(9) neutrons/cm(2) and 3 x 10(10) alpha-particles/cm(2). This fluence is characteristic for fission experiments. The pre-requisite for the observed signal stability is the application of priming of the diamond material with a strong beta-source for about 48 h. The intrinsic timing resolution of a 100 mu m thick polycrystalline CVD diamond detector with a size of 1 x 1 cm(2) was determined to sigma(int) = (283 +/- 41) ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180 mu m show an intrinsic timing resolution of sigma(int) = (106 +/- 21) ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%.

  • 25.
    Oberstedt, S.
    et al.
    European Commission JRC-IRMM, Institute for Reference Materials and Measurements, Geel, Belgium.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Birgersson, Evert
    Örebro University, School of Science and Technology.
    Fabry, I.
    European Commission JRC-IRMM, Institute for Reference Materials and Measurements, Geel, Belgium.
    Hambsch, F. J.
    European Commission JRC-IRMM, Institute for Reference Materials and Measurements, Geel, Belgium.
    Kornilov, N.
    European Commission JRC-IRMM, Institute for Reference Materials and Measurements, Geel, Belgium.
    Lövestam, G.
    European Commission JRC-IRMM, Institute for Reference Materials and Measurements, Geel, Belgium.
    Tudora, A.
    Bucharest University, Bucharest, Romania.
    First results on the neutron-induced fission cross-section of Pa-231 for incident neutron energies E-n > 17 MeV2012In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 43, p. 26-30Article in journal (Refereed)
    Abstract [en]

    First results on the neutron-induced fission cross-section of Pa-231 for incident neutron energies E-n > 17 MeV are presented. The experiments were carried out with quasi mono-energetic neutrons produced in the reaction T(d, n)He-4. Corrections for low-energy neutron background produced in this reaction at incident deuteron energies E-d > 2 MeV are taken into account and based on experimental data obtained by two different techniques. Despite the relatively large error bars at the higher neutron energies, the new cross-section values meet the accuracy requirements set by the IAEA and will allow to remove the hitherto existing large spread between different previously published data. Recent cross-section calculations describe well the new experimental results, which are in consistency with cross-section values obtained in a particle-transfer reaction at excitation energies corresponding to neutron energies E-n < 10 MeV. 

  • 26. Oberstedt, Stephan
    et al.
    Gawrys, M.
    Lövestam, Göran
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Plompen, Arjan
    Semkova, Valentina
    NEPTUNE: the new isomer spectrometer at IRMM2007In: NEMEA-3: neutron measurements, evaluations and applications : proceedings of the enlargement workshop / [ed] Arjan J. M. Plompen, 2007, , p. 4p. 93-97Conference paper (Refereed)
  • 27. Oberstedt, Stephan
    et al.
    Hambsch, Franz-Josef
    Kornilov, Nicolai
    Lövestam, Göran
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Gawrys, Mikael
    Shape isomers: a key to fission barriers2008In: Seminar on Fission VI, Corsendonk Priory, Belgium, September 18-21, 2007 / [ed] Cyriel Wagemans, Jan Wagemans, Pierre D'hondt, 2008, , p. 8p. 233-240Conference paper (Refereed)
    Abstract [en]

    Quantitative predictions of fission product yields are relevant for the reliable operation of different modern nuclear applications. This concerns the realistic characterizations of the radio-toxicity of the fuel elements after the envisaged extended irradiation, as well as sub-critical assemblies, where the number of delayed neutrons from minor actinides is determined by the characteristic emission yields of the corresponding so-called pre-cursor isotopes. However, to be able to make more reliable quantitative predictions of fission characteristics requires the better understanding of the fission process itself. For this purpose a better knowledge about the distinct structure of the nuclear energy landscape around the fission barrier is indispensable. In particular, the question should be answered, whether the fission barrier is either double- or triple-humped or even multi-humped as been proposed within the multi-modal neck rupture model. Despite quite some effort based on different experimental techniques and theoretical approaches, this question remains still unanswered. There is still no consistent picture of the fission barrier available and hence, different sets of barrier parameters are in use, unable to describe the different observed phenomena in a coherent way. With the systematic investigation of shape isomer population, its decay modes as well as the branching ratio, precise information can be obtained to resolve the puzzling situation. The experimental approach will be discussed and results from first experiments presented.

  • 28. Oberstedt, Stephan
    et al.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Fritsch, Volker
    Lövestam, Göran
    Kornilov, Nikolai
    New results on the neutron-induced fission cross-section of 231Pa for incident neutron energies En = 0.8 to 3.5 MeV2005In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 32, no 17, p. 1867-1874Article in journal (Refereed)
  • 29. Oberstedt, Stephan
    et al.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Hambsch, Franz-Josef
    Fritsch, Volker
    Vladuca, Gheorghita
    Tudora, Annabella
    Neutron-induced fission cross-section of 231Pa2006In: Proceedings of NEMEA-2 Workshop on Neutron Measurements, Evaluations and Applications - 2, October 20-23, 2004, Bucharest, Rumania, EUR Report 22136 EN, 2006Conference paper (Refereed)
  • 30. Oberstedt, Stephan
    et al.
    Oberstedt, Andreas
    Örebro University, School of Science and Technology.
    Plompen, Arjan
    Semkova, Valentina
    Lövestam, Göran
    Gawrys, Mikael
    Research on isomer decay with the NEPTUNE spectrometer2008In: ND-2007 International Conference on Nuclear Data for Science and Technology, Nice, France, Les Ulis Cedex A, France: EDP Sciences , 2008, , p. 4p. 53-56Conference paper (Refereed)
    Abstract [en]

    A new spectrometer has been built at the EC-JRC IRMM to investigate isomer decay in the millisecond range and activation cross sections of isotopes, where isomeric states exist and are populated. The spectrometer is equipped with high-resolution gamma-ray detectors and an ionisation chamber for the measurement of charged particles, e.g., fission fragments. NEPTUNE provides pulsed quasi mono-energetic neutrons at pulse repetition frequencies up to 5 kHz and tuneable neutron pulse widths ranging from 10 µs into the ms-region. For this purpose a beam chopper based on a parallel-plate capacitor has been integrated into the accelerator beam line in order to deflect the charged-particle beam onto a tantalum beam dump. First research has been performed with the NEPTUNE spectrometer dedicated to the shape isomer search in the odd-A uranium isotopes 235U, 237U and 239U. In further experiments the population of long-lived spin isomers was investigated.

  • 31. Oberstedt, Stephan
    et al.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Rochman, Dimitri
    Gönnenwein, Friedrich
    Tsekhanovich, Igor
    Becker, Julia
    Örebro University, Department of Natural Sciences.
    Sartz, Annika
    Örebro University, Department of Natural Sciences.
    Bax, Hugo
    Hambsch, Franz-Josef
    Raman, Subramanian
    Light charged particle emission in the reaction 251Cf(nth, f)2005In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 761, no 3-4, p. 173-189Article in journal (Refereed)
    Abstract [en]

    High resolution measurements of light charged particles (LCP) emitted in thermal neutron-induced fission of 252Cf ∗ (E=6.2 MeV) have been performed with the recoil mass-separator LOHENGRIN. For this compound nuclear system emission yields of LCPs, their mean kinetic energies and widths have been obtained for 8 isotopes with nuclear charges Z⩾2. For 13 further isotopes the emission yields were estimated on the basis of systematics on their kinetic energy distributions. 34Al and 36Si emission has been observed for the first time in thermal neutron-induced fission.

  • 32.
    Tovesson, Fredrik
    et al.
    Örebro University, Department of Natural Sciences.
    Birgersson, E.
    Örebro University, Department of Natural Sciences.
    Flenéus, M.
    Örebro University, Department of Natural Sciences.
    Fogelberg, B.
    Fritsch, V.
    Gustafsson, C.
    Örebro University, Department of Natural Sciences.
    Hambsch, F.-J.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Oberstedt, Stephan
    Ramström, E.
    Tudora, A.
    Vladuca, G.
    233Pa(n, f) cross section up to En=8.5 MeV2004In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 733, no 1-2, p. 3-19Article in journal (Refereed)
    Abstract [en]

    The energy dependence of the neutron-induced fission cross section of 233Pa has been measured directly for the first time from the fission threshold up to En=8.5 MeV. This reaction plays an important role in the thorium-uranium fuel cycle, and is thus of interest for the design and modeling of advanced reactor and transmutation facilities. The existing information in the ENDF/B-VI and JENDL-3.3 evaluated nuclear data files differ by a factor of two for the 233Pa(n, f) cross section values and show different fission threshold energies. Our new experimental data give lower cross section values than both evaluations and resolves the question about the threshold energy. In addition to the experimental investigation, also a new theoretical calculation of the reaction cross section has been performed with the statistical model code STATIS, showing a good agreement with the experimental data.

  • 33.
    Tovesson, Fredrik
    et al.
    Örebro University, Department of Natural Sciences.
    Hambsch, F.-J.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Fogelberg, B.
    Ramström, E.
    Oberstedt, Stephan
    Neutron-induced fission cross section of 233Pa between 1.0 and 3.0 MeV2002In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 88, no 6, p. 062502-Article in journal (Refereed)
    Abstract [en]

    The energy dependent neutron-induced fission cross section of 233Pa has for the first time been measured directly with monoenergetic neutrons. This nuclide is an important intermediary in a thorium based fuel cycle, and its fission cross section is a key parameter in the modeling of future advanced fuel and reactor concepts. A first experiment resulted in four cross section values between 1.0 and 3.0 MeV, establishing a fission threshold in excess of 1 MeV. Significant discrepancies were found with a previous indirect experimental determination and with model estimates.

  • 34.
    Tovesson, Fredrik
    et al.
    Örebro University, Department of Natural Sciences.
    Hambsch, F.-J.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Fogelberg, B.
    Ramström, E.
    Oberstedt, Stephan
    The Pa-233 fission cross section2002In: Journal of Nuclear Science and Technology, ISSN 0022-3131, E-ISSN 1881-1248, Vol. Supplement 2, p. 210-213Article in journal (Refereed)
    Abstract [en]

    The energy dependent neutron-induced fission cross section of 233Pa has for the first time been measured directly with mono-energetic neutrons. This isotope is produced in the thorium fuel cycle and serves as an intermediate step between the 232Th source material and the 233U fuel material. Four neutron energies between 1.0 and 3.0 MeV have been measured in a first campaign. Some preliminary results are presented and compared to literature.

  • 35. Vladuca, G.
    et al.
    Hambsch, F.-J.
    Tudora, A.
    Oberstedt, S.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Tovesson, F.
    Örebro University, Department of Natural Sciences.
    Filipescu, D.
    Calculation of the neutron-induced fission cross section of 233Pa up to 20 MeV2004In: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 740, no 1-2, p. 3-19Article in journal (Refereed)
    Abstract [en]

    Since very recently, direct measurements of the 233Pa(n,f) cross-section are available in the energy range from 1.0 to 8.5 MeV. This has stimulated a new, self-consistent, neutroncross-section evaluation for the n+233Pa system, in the incident neutron energy range 0.01–20MeV. Since higher fission chances are involved also the lighter Pa-isotopes had to be re-evaluated in a consistent manner. The results are quite different compared to earlier evaluation attempts. Since 233Pa is a key isotope in the thorium based fuel cycle the quality of its reaction cross-sections is important for the modeling of future advanced fuel and reactor concepts. The present status of the evaluated libraries is that they differ by a factor of two in the absolute fissioncross-section and also in the threshold energy value.

  • 36. Vladuca, G.
    et al.
    Hambsch, F.-J.
    Tudora, A.
    Oberstedt, Stephan
    Tovesson, Fredrik
    Örebro University, Department of Natural Sciences.
    Oberstedt, Andreas
    Örebro University, Department of Natural Sciences.
    Filipescu, D.
    Calculation of the neutron-induced fission cross section of 233Pa2004In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 69, no 2, p. 021604-Article in journal (Refereed)
    Abstract [en]

    Since very recently, experimental data for the energy dependence of the 233Pa(n,f) cross section are finally available. This has stimulated a new, self-consistent cross section evaluation for the system n+233Pa in the incident neutron energy range 0.01–6 MeV. The results are quite different compared to earlier evaluation attempts. Since 233Pa is an important intermediary in the thorium based fuel cycle, its neutron reaction cross sections are key parameters in the modeling of future advanced reactor concepts.

1 - 36 of 36
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