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  • 251. Gherendi, M.
    et al.
    Zoita, V. L.
    Craciunescu, T.
    Johnson, M. G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Pantea, A.
    Baltog, I.
    Edlington, T.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kiptily, V.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Murari, A.
    Popovichev, S.
    Neutron field parameter measurements on the JET tokamak by means of super-heated fluid detectors2012In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, no 10, p. 10E124-Article in journal (Refereed)
    Abstract [en]

    The neutron field parameters (fluence and energy distribution) at a specific location outside the JET Torus Hall have been measured by means of super-heated fluid detectors (or bubble detectors) in combination with an independent, time-of-flight, technique. The bubble detector assemblies were placed at the end of a vertical line of sight at about 16 m from the tokamak mid plane. Spatial distributions of the neutron fluence along the radial and toroidal directions have been obtained using two-dimensional arrays of bubble detectors. Using a set of three bubble detector spectrometers the neutron energy distribution was determined over a broad energy range, from about 10 keV to above 10 MeV, with an energy resolution of about 30% at 2.5 MeV. The very broad energy response allowed for the identification of energy features far from the main fusion component (around 2.45 MeV for deuterium discharges).

  • 252.
    Giacomelli, L.
    et al.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.
    Belli, F.
    ENEA CR Frascati, Dipartimento FSN, Rome, Italy.
    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.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Milocco, A.
    Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy;Culham Sci Ctr, CCFE, Abingdon, Oxon, England.
    Popovicev, S.
    Culham Sci Ctr, CCFE, Abingdon, Oxon, England.
    Syme, D. B.
    Culham Sci Ctr, CCFE, Abingdon, Oxon, England.
    Neutron emission spectroscopy of D plasmas at JET with a compact liquid scintillating neutron spectrometer2018In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 89, no 10, article id 10I113Article in journal (Refereed)
    Abstract [en]

    Neutron emission spectroscopy is a diagnostic technique that allows for energy measurements of neutrons born in nuclear reactions. The JET tokamak fusion experiment (Culham, UK) has a special role in this respect as advanced spectrometers for 2.5 MeV and 14 MeV neutrons have been developed here for the first time for measurements of the neutron emission spectrum from D and DT plasmas with unprecedented accuracy. Twin liquid scintillating neutron spectrometers were built and calibrated at the Physikalisch-Technische Bundesanstalt (PTB) (Braunschweig, Germany) and installed on JET in the recent years with tangential-equatorial (KM12) and vertical-radial (KM13) view lines, with the latter only recently operational. This article reports on the performance of KM12 and on the development of the data analysis methods in order to extract physics information upon D ions kinematics in JET auxiliary-heated D plasmas from 2.5 MeV neutron measurements. The comparison of these results with the correspondents from other JET neutron spectrometers is also presented: their agreement allows for JET unique capability of multi-lines of sight neutron spectroscopy and for benchmarking other 14 MeV neutron spectrometers installed on the same lines of sight in preparation for the DT experimental campaign at JET.

  • 253. Giacomelli, L.
    et al.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G.
    Horton, L.
    Murari, A.
    Popovichev, S.
    Syme, D. B.
    Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 2, p. 023505-Article in journal (Refereed)
    Abstract [en]

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/gamma discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

  • 254.
    Giacomelli, L.
    et al.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy..
    Nocente, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Rebai, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Rigamonti, D.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Milocco, A.
    Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Tardocchi, M.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy..
    Chen, Z. J.
    Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China..
    Du, T. F.
    Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China..
    Fan, T. S.
    Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China..
    Hu, Z. M.
    Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China..
    Peng, X. Y.
    Peking Univ, State Key Lab Nucl Phys & Technol, Sch Phys, Beijing, Peoples R China..
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gorini, G.
    CNR, Ist Fis Plasma P Caldirola, Milan, Italy.;Univ Milano Bicocca, Dipartimento Fis G Occhialini, Milan, Italy..
    Neutron emission spectroscopy of DT plasmas at enhanced energy resolution with diamond detectors2016In: REVIEW OF SCIENTIFIC INSTRUMENTS, ISSN 0034-6748, Vol. 87, no 11, article id 11D822Article in journal (Refereed)
    Abstract [en]

    This work presents measurements done at the Peking University Van de Graaff neutron source of the response of single crystal synthetic diamond (SD) detectors to quasi-monoenergetic neutrons of 14-20 MeV. The results show an energy resolution of 1% for incoming 20 MeV neutrons, which, together with 1% detection efficiency, opens up to new prospects for fast ion physics studies in high performance nuclear fusion devices such as SD neutron spectrometry of deuterium-tritium plasmas heated by neutral beam injection.

  • 255.
    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.

  • 256. Girardo, Jean-Baptiste
    et al.
    Sharapov, Sergei
    Boom, Jurrian
    Dumont, Rémi
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Fitzgerald, Michael
    Garbet, Xavier
    Hawkes, Nick
    Kiptily, Vasily
    Lupelli, Ivan
    Mantsinen, Mervi
    Sarazin, Yanick
    Schneider, Mireille
    Contributors, JET
    Stabilization of sawteeth with third harmonic deuterium ICRF-accelerated beam in JET plasmas2016In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 23, no 1, article id 012505Article in journal (Refereed)
    Abstract [en]

    Sawtooth stabilisation by fast ions is investigated in deuterium (D) and D-helium 3 (He3) plasmas of JET heated by deuterium Neutral Beam Injection combined in synergy with Ion Cyclotron Resonance Heating (ICRH) applied on-axis at 3rd beam cyclotron harmonic. A very significant increase in the sawtooth period is observed, caused by the ICRH-acceleration of the beam ions born at 100 keV to the MeV energy range. Four representative sawteeth from four different discharges are compared with Porcelli's model. In two discharges, the sawtooth crash appears to be triggered by core-localized Toroidal Alfvén Eigenmodes inside the q = 1 surface (also called “tornado” modes) which expel the fast ions from within the q = 1 surface, over time scales comparable with the sawtooth period. Two other discharges did not exhibit fast ion-driven instabilities in the plasma core, and no degradation of fast ion confinement was found in both modelling and direct measurements of fast ion profile with the neutroncamera. The developed sawtooth scenario without fast ion-driven instabilities in the plasma core is of high interest for the burning plasmas. Possible causes of the sawtooth crashes on JET are discussed.

  • 257.
    Glechner, T.
    et al.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Mayrhofer, P. H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Holec, D.
    Univ Leoben, Dept Mat Sci, A-8700 Leoben, Austria.
    Fritze, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Paneta, Valentina
    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.
    Kolozsvari, S.
    Plansee Composite Mat GmbH, D-86983 Lechbruck, Germany.
    Riedl, H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Tuning structure and mechanical properties of Ta-C coatings by N-alloying and vacancy population2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 17669Article in journal (Refereed)
    Abstract [en]

    Tailoring mechanical properties of transition metal carbides by substituting carbon with nitrogen atoms is a highly interesting approach, as thereby the bonding state changes towards a more metallic like character and thus ductility can be increased. Based on ab initio calculations we could prove experimentally, that up to a nitrogen content of about 68% on the non-metallic sublattice, Ta-C-N crystals prevail a face centered cubic structure for sputter deposited thin films. The cubic structure is partly stabilized by non-metallic as well as Ta vacancies-the latter are decisive for nitrogen rich compositions. With increasing nitrogen content, the originally super-hard fcc-TaC0.71 thin films soften from 40 GPa to 26 GPa for TaC0.33N0.67, accompanied by a decrease of the indentation modulus. With increasing nitrogen on the non-metallic sublattice (hence, decreasing C) the damage tolerance of Ta-C based coatings increases, when characterized after the Pugh and Pettifor criteria. Consequently, varying the non-metallic sublattice population allows for an effective tuning and designing of intrinsic coating properties.

  • 258.
    Gleich, Stephan
    et al.
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany..
    Soler, Rafael
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany..
    Fager, Hanna
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.;Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Bolvardi, Hamid
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Achenbach, Jan-Ole
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, Marcus
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Schneider, Jochen M.
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.;Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Dehm, Gerhard
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany..
    Scheu, Christina
    Max Planck Inst Eisenforsch GmbH, Max Planck Str 1, D-40237 Dusseldorf, Germany.;Rhein Westfal TH Aachen, Mat Analyt, Kopernikusstr 10, D-52074 Aachen, Germany..
    Modifying the nanostructure and the mechanical properties of Mo2BC hard coatings: Influence of substrate temperature during magnetron sputtering2018In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 142, p. 203-211Article in journal (Refereed)
    Abstract [en]

    A reduction in synthesis temperature is favorable for hard coatings, which are designed for industrial applications, as manufacturing costs can be saved and technologically relevant substrate materials are often temperature-sensitive. In this study, we analyzed Mo2BC hard coatings deposited by direct current magnetron sputtering at different substrate temperatures, ranging from 380 degrees C to 630 degrees C. Transmission electron microscopy investigations revealed that a dense structure of columnar grains, which formed at a substrate temperature of 630 degrees C, continuously diminishes with decreasing substrate temperature. It almost vanishes in the coating deposited at 380 degrees C, which shows nanocrystals of similar to 1 nm in diameter embedded in an amorphous matrix. Moreover, Argon from the deposition process is incorporated in the film and its amount increases with decreasing substrate temperature. Nanoindentation experiments provided evidence that hardness and Young's modulus are modified by the nanostructure of the analyzed Mo2BC coatings. A substrate temperature rise from 380 degrees C to 630 degrees C resulted in an increase in hardness (21 GPa to 28 GPa) and Young's modulus (259 GPa to 462 GPa). We conclude that the substrate temperature determines the nanostructure and the associated changes in bond strength and stiffness and thus, influences hardness and Young's modulus of the coatings.

  • 259. Goebl, D.
    et al.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abad, E.
    Monreal, R. C.
    Bauer, P.
    Auger neutralization of He+ on Cu surfaces: Simulation of azimuthal scans2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 317, no Part A, p. 23-27Article in journal (Refereed)
    Abstract [en]

    Charge exchange by Auger neutralization (AN) plays an important role in surface analysis techniques such as low energy ion scattering (LEIS). Recent advances in the theoretical description of AN have included a model based on a linear combination of atomic orbitals (LCAO) approach, which is able to calculate accurate neutralization probabilities of He+ due to AN in LEIS. Previous investigations have shown that the neutralization probability is strongly influenced by the distance dependent shift of the He 1s level. In this study simulations of He+ scattered from Cu(100) and Cu(110) surfaces at fixed azimuth angles are presented. Additionally, the azimuth dependence of ion- and neutral-yield for He+ scattered from Cu(100) is simulated and compared to experimental data. Calculations were performed using the LCAO model in combination with molecular dynamics simulations. The excellent agreement between simulation and experiment provides evidence that the obtained values for the level shift are a characteristic property of the surface.

  • 260. Goebl, D.
    et al.
    Roth, D.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Monreal, R. C.
    Abad, E.
    Putz, A.
    Bauer, P.
    Quasi-resonant neutralization of He+ ions at a germanium surface2013In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 25, no 48, p. 485006-Article in journal (Refereed)
    Abstract [en]

    When low-energy He ions are scattered from a Ge surface, the fraction of positive ions exhibits characteristic oscillations as a function of ion energy. These oscillations are caused by quasi-resonant neutralization (qRN), a process which is active for materials with a narrow band nearly resonant with the unperturbed He 1s-level. In this paper we measure the fraction of He+ backscattered from Ge(100). In conjunction with recently developed theoretical methods, we extract quantitative information on the efficiency of qRN. Our evaluation reveals that qRN is a highly efficient process leading to ion fractions two orders of magnitude lower than in systems for which neutralization is only due to Auger processes.

  • 261. Gorelov, D.
    et al.
    Eronen, T.
    Hakala, J.
    Jokinen, A.
    Kankainen, A.
    Kolhinen, V.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moore, I.
    Penttilä, H.
    Pohjalainen, I.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Reponen, M.
    Rinta-Antila, S.
    Rubchenya, V.
    Saastamoinen, A.
    Simutkin, V.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sonnenschein, V.
    Äystö, J.
    Erratum to: “Measuring independent yields of fission products using a penning trap”2015In: Bulletin of the Russian Academy of Sciences: Physics, ISSN 1934-9432, Vol. 79, no 10, p. 1315-1315Article in journal (Refereed)
  • 262. Gorelov, D.
    et al.
    Eronen, T.
    Hakala, J.
    Jokinen, A.
    Kankainen, A.
    Kolhinen, V.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moore, I.
    Penttilä, H.
    Pohjalainen, I.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Reponen, M.
    Rinta-Antila, S.
    Rubchenya, V.
    Saastamoinen, A.
    Simutkin, V.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sonnenschein, V.
    Äystö, J.
    Measuring independent yields of fission products using a penning trap2015In: Bulletin of the Russian Academy of Sciences: Physics, ISSN 1062-8738, Vol. 79, no 7, p. 869-871Article in journal (Refereed)
    Abstract [en]

    A new method for determining independent fission products is used in an experiment at the Accelerator Laboratory of the University of Jyväskylä. The method combines the chemical universality of the ion guide technique and the unique properties of the Penning trap. A beam of charged particles is formed by stopping fission products in gaseous helium. The Penning trap is employed as a highly accurate filter to identify particles by their mass. The yields of fission products are determined by the ion count downstream of the trap. The setup’s mass resolving power is on the order of 105 with a radio frequency excitation time of 400 ms. Such high mass resolution occasionally allows us not only to separate nuclides but to separate the isomeric and ground states of nuclei as well. Independent yields of fission products are measured in the fission reaction of the 232Th isotope by protons with an energy of 25 MeV. A short description of the method ae nd soexperimental data are supplememnted by the results fro theoretical calculations.

  • 263. Gorelov, D.
    et al.
    Hakala, J.
    Jokinen, A.
    Kolhinen, V.
    Koponen, J.
    Moore, I.
    Penttila, H.
    Pohjalainen, I.
    Reponen, M.
    Rinta-Antila, S.
    Sonnenschein, V.
    Voss, A.
    Al-Adili, Ali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simutkin, Vasily
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Aysto, J.
    Isomeric Yield Ratios of Fission Products Measured with the Jyfltrap2014In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 45, no 2, p. 211-216Article in journal (Refereed)
    Abstract [en]

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

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

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

  • 265.
    Gorelov, D.
    et al.
    University of Jyväskylä.
    Penttilä, H.
    University of Jyväskylä.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Measurement of Isomeric Yield Ratios of Fission Products with the Jyfltrap2014In: Fission and Properties of Neutron-Rich Nuclei - Proceedings of the Fifth International Conference on ICFN5. Edited by Hamilton Joseph H & Ramayya Akunuri V. Published by World Scientific Publishing Co. Pte. Ltd., 2014. ISBN #9789814525435, pp. 252-257, 2014, p. 252-257Conference paper (Refereed)
  • 266. Gorelov, D.A.
    et al.
    Eronen, T.
    Hakala, J.
    Jokinen, A.
    Kankainen, A.
    Kolhinen, V.S.
    Lantz, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Mattera, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moore, I.
    Penttilä, H.
    Pohjalainen, I.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Reponen, M.
    Rinta-Antila, S.
    Rissanen, J.
    Rubchenya, V.
    Saastamoinen, A.
    Simutkin, V.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sonnenschein, V.
    Äysto, J.
    Independent fission yield measurements with jyfltrap2014In: Минск: Изд. центр БГУArticle in journal (Other academic)
  • 267.
    Gottfridsson, Filip
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simulation of Reactor Transient and Design Criteria of Sodium-cooled Fast Reactors2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for energy is growing in the world and the market of nuclear power is now once more expanding. Some issues of the current light-water reactors can be solved by the next generation of nuclear power, Generation IV, where sodium-cooled reactors are one of the candidates. Phénix was a French prototype sodium-cooled reactor, which is seen as a success. Although it did encounter an earlier unexperienced phenomenon, A.U.R.N., in which a negative reactivity transient followed by an oscillating behavior forced an automatic emergency shutdown of the reactor. This phenomenon lead to a lot of downtime of the reactor and is still unsolved. However, the most probable cause of the transients is radial movements of the core, referred to as core-flowering.

    This study has investigated the available documentation of the A.U.R.N. events. A simplified model of core-flowering was also created in order to simulate how radial expansion affects the reactivity of a sodium-cooled core. Serpent, which is a Monte-Carlo based simulation code, was chosen as calculation tool. Furthermore, a model of the Phénix core was successfully created and partly validated. The model of the core has a k_eff = 1.00298 and a neutron flux of (8.43+-0.02)!10^15 neutrons/cm^2 at normal state. The result obtained from the simulations shows that an expansion of the core radius decreases the reactivity. A linear approximation of the result gave the relation: change in k_eff/core extension = - 60 pcm/mm. This value corresponds remarkably well to the around - 60 pcm/mm that was obtained from the dedicated core-flowering experiments in Phénix made by the CEA.

    Core-flowering can recreate similar signals to those registered during the A.U.R.N. events, though the absence of trace of core movements in Phénix speaks against this. However, if core-flowering is the sought answer, it can be avoided by design. The equipment that registered the A.U.R.N. events have proved to be insensitive to noise. Though, the high amplitude of the transients and their rapidness have made some researcher believe that the events are a combination of interference in the equipment of Phénix and a mechanical phenomenon. Regardless, the origin of A.U.R.N. seems to be bound to some specific parameter of Phénix due to the fact that the transients only have occurred in this reactor.

    A safety analysis made by an expert committee, appointed by CEA, showed that the A.U.R.N. events are not a threat to the safety of Phénix. However, the origin of these negative transients has to be found before any construction of a commercial size sodium-cooled fast reactor can begin. Thus, further research is needed.

  • 268.
    Graf Brolund, Alice
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Persson, Rebecca
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Investigating the properties of Planck's radiation law through theoretical and numerical studies2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A black body is an ideal object that absorbs all incident electromagnetic radiation and simultaneously emits radiation that only depends on the temperature. The radiation is described by Planck's radiation law and its maximum by Wien's displacement law. The aim of this project is to study Planck's and Wien's laws in the frequency and wavelength domains, by theoretical studies and numerical studies in the programming language Python. Planck's law can be derived by regarding a cavity where the internal radiation either can be regarded as waves or as a gas of photons. In this study, the main focus lies in the derivation assuming radiation can be treated as waves, which uses the Maxwell-Boltzmann distribution. This derivation is also used when the radiation is simulated numerically in Python. The numerical studies use the stochastic method "hit and miss" to generate the different properties of the emitted radiation. Planck's law occurs in many different forms, the differences between some of them is explained in this project.

    When transforming between the domains one must use a Jacobian. If this is forgotten Wien's law, which is derived from Planck’s law, efficiently shows how the peaks of the correct and the transformed curves are at different positions. The results show that Planck's law accurately can be derived numerically. Even though the chosen method successfully reproduces the Planck distribution the program can be improved by using the inverse transform method for sampling. To study this subject further one could consider deriving and simulating the Maxwell-Boltzmann distribution.

  • 269.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Basic facts and definitions related to measurement2015In: The new nuclear forensics: Analysis of nuclear materials for security purposes / [ed] Vitaly Fedchenko, Great Britain: Oxford University Press, 2015, 1Chapter in book (Refereed)
  • 270.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Gamma spectroscopy as a tool of non-destructive nuclear forensic analysis2015In: The new nuclear forensics: Analysis of nuclear materials for security purposes / [ed] Vitaly Fedchenko, Great Britain: Oxford University Press, 2015, 1Chapter in book (Refereed)
  • 271.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Statistical grounds for determining the ability to detect partial defects using the Digital Cherenkov Viewing Device (DCVD)2010Report (Other academic)
    Abstract [en]

    The DCVD (Digital Cherenkov Viewing Device), and its predecessor the CVD (CherenkovViewing Device), has been used by the IAEA to inspect gross defects in spent fuel. The time has now come to also write a report on the instrument’s ability to detect partial defects at the 50% level. Before this report can be finalized, the capabilities of the DCVD must of course be investigated and quantified. Discussions have arisen within the DCVD-group how this can and should be done.

  • 272.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Recent modelling studies for analysing the partial-defect detection capability of the Digital Cherenkov Vieweing Device2014In: Esarda Bulletin, ISSN 0392-3029, no 51, p. 3-8Article in journal (Refereed)
    Abstract [en]

    Strong sources of radioactivity, such as spent nuclear fuel stored in water pools, give rise to Cherenkov light. This light originates from particles, in this case electrons released from gamma-ray interactions, which travel faster than the speed of light in the water. In nuclear safeguards, detection of the Cherenkov light intensity is used as a means for verifying gross and partial defect of irradiated fuel assemblies in wet storage.

     

    For spent nuclear fuel, the magnitude of the Cherenkov light emission depends on the initial fuel enrichment (IE), the power history (in particular the total fuel burnup (BU)) and the cooling time (CT). This paper presents recent results on the expected Cherenkov light emission intensity obtained from modelling a full 8x8 BWR fuel assembly with varying values of IE, BU and CT. These results are part of a larger effort to also investigate the Cherenkov light emission for fuels with varying irradiation history and other fuel geometries in order to increase the capability to predict the light intensity and thus lower the detection limits for the Digital Cherenkov Viewing Device (DCVD).

     

    The results show that there is a strong dependence of the Cherenkov light intensity on BU and CT, in accordance with previous studies. However, the dependences demonstrated previously are not fully repeated; the current study indicates a less steep decrease of the intensity with increasing CT. Accordingly, it is suggested to perform dedicated experimental studies on fuel with different BU and CT to resolve the differences and to enhance future predictive capability. In addition to this, the dependence of the Cherenkov light intensity on the IE has been investigated. Furthermore, the modelling of the Cherenkov light emission has been extended to CTs shorter than one year. The results indicate that high-accuracy predictions for short-cooled fuel may require more detailed information on the irradiation history.

  • 273.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    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.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Åberg Lindell, Matilda
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    New perspectives on nuclear power - Generation IV nuclear energy systems to strengthen nuclear non-proliferation and support nuclear disarmament2014In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 73, p. 815-819Article in journal (Refereed)
    Abstract [en]

    Recently, nuclear power has received support from environmental and climate researchers emphasizing the need to address factors of global importance such as climate change, peace and welfare. Here, we add to previous discussions on meeting future climate goals while securing safe supplies of energy by discussing future nuclear energy systems in the perspective of strengthening nuclear non-proliferation and aiding in the process of reducing stockpiles of nuclear weapons materials.

    New nuclear energy systems, currently under development within the Generation IV (Gen IV) framework, are being designed to offer passive safety and inherent means to mitigate consequences of nuclear accidents. Here, we describe how these systems may also be used to reduce or even eliminate stockpiles of civil and military plutonium—the former present in waste from today׳s reactors and the latter produced for weapons purposes. It is argued that large-scale implementation of Gen IV systems would impose needs for strong nuclear safeguards. The deployment of Safeguards-by-Design principles in the design and construction phases can avoid draining of IAEA resources by enabling more effective and cost-efficient nuclear safeguards, as compared to the current safeguards implementation, which was enforced decades after the first nuclear power plants started operation.

  • 274.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    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.
    Branger, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Forskning inom teknisk kärnämneskontroll vid Uppsala universitet under 2014–20152016Report (Other academic)
    Abstract [sv]

    Uppsala universitet har inom ramen för olika avtal med SSM under 2014-2015 bedrivit ett omfattande forskningsprogram inom kärnämneskontroll. Forskningsprogrammet har under denna tid innefattat 3 doktorander med dedikerade forskningsprojekt och ett flertal seniora forskare som helt eller delvis har varit engagerade inom kärnämneskontroll.

    Denna rapport uppmärksammar särskilt fyra forskningsområden av hög relevans för den globala kärnämneskontrollen, vilka benämns; DCVD, Next Generation Safeguards Initiative, verifiering av atypiska bränsleobjekt och Generation IV kärnkraftsystem. Även andra forskningsaktiviteter har genomförts inom ramen för forskningsprogrammet, vilka dock ligger utanför redovisningen i denna rapport.

    Under perioden 2014-2015 producerades inom forskningsprogrammet 9 artiklar som skickats till vetenskapliga tidskrifter med peer-review-granskning. Därutöver gjordes medvetna satsningar på att lyfta fram forskningen på de arenor som är av störst betydelse för det internationella kärnämneskontrollarbetet, d.v.s. på de symposier och möten som arrangeras av FN:s internationella atomenergiorgan (IAEA), det europeiska samarbetsorganet ESARDA och den amerikanska organisationen INMM. Vid dessa internationella konferenser publicerades ytterligare 15 vetenskapliga artiklar med unikt innehåll under perioden. En publikationslista med samtliga forskningsarbeten som producerats under perioden redovisas i denna rapport.

  • 275.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    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.
    Students’ approaches to learning from other students’ oral presentations2013Conference paper (Other academic)
    Abstract [en]

    A phenomenographic study has been performed in order to investigate students’ approaches to learning from other students’ oral presentations in the context of a compulsory seminar on nuclear accidents in the third year of the nuclear engineering programme at Uppsala University.

  • 276.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lindberg, Bo
    Recent modelling studies for analysing the partial-defect detection capability of theDigital Cherenkov Viewing Device2013Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is an instrument available to IAEA inspectors forverifying spent nuclear fuel in wet storage at nuclear facilities. The instrument records the Cherenkovlight that is emitted in the water surrounding the highly radioactive fuel. The light intensity is largelydependent on the amount of nuclear material in the fuel as well as its burnup and cooling time and can beused by the inspector as a measure for verifying the properties of the fuel.To aid in the analysis of the Cherenkov light intensity, a simulation toolkit has been developed, whichmodels the emission, transport and detection of Cherenkov light. This toolkit is particularly useful forinvestigating the response of the DCVD for fuel assemblies subject to different types of partial defects,where fuel rods might have been removed or substituted with non-irradiated material. Variousconfigurations of partial defects may be simulated in order to evaluate the detection capabilities of theDCVD.Here, we present how the light intensity recorded by the DCVD is affected by the fuel history and by thepartial defect scenario. We present a methodology for how the analysis and interpretation of recordedintensities may be performed to result in confidence-supported statements of different levels of partialdefect. Finally, we suggest topics for further studies to accomplish an automated inspection system based on this methodology.

  • 277.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lindberg, Bo
    Verifying nuclear fuel assemblies in wet storages on a partial defect level: A software simulation tool for evaluating the capabilities of the Digital Cherenkov Viewing Device2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 698, p. 66-71Article in journal (Refereed)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is an instrument that records the Cherenkov light emitted from irradiated nuclear fuels in wet storages. The presence, intensity and pattern of the Cherenkov light can be used by the International Atomic Energy Agency (IAEA) inspectors to verify that the fuel properties comply with declarations. The DCVD is since several years approved by the IAEA for gross defect verification, i.e. to control whether an item in a storage pool is a nuclear fuel assembly or a non-fuel item [1]. Recently, it has also been endorsed as a tool for partial defect verification, i.e. to identify if a fraction of the fuel rods in an assembly have been removed or replaced. The latter recognition was based on investigations of experimental studies on authentic fuel assemblies and of simulation studies on hypothetic cases of partial defects [2]. This paper describes the simulation methodology and software which was used in the partial defect capability evaluations. The developed simulation procedure uses three stand-alone software packages: the ORIGEN-ARP code [3] used to obtain the gamma-ray spectrum from the fission products in the fuel, the Monte Carlo toolkit Geant4 [4] for simulating the gamma-ray transport in and around the fuel and the emission of Cherenkov light, and the ray-tracing programme Zemax [5] used to model the light transport through the assembly geometry to the DCVD and to mimic the behaviour of its lens system. Furthermore, the software allows for detailed information from the plant operator on power and/or burnup distributions to be taken into account to enhance the authenticity of the simulated images. To demonstrate the results of the combined software packages, simulated and measured DCVD images are presented. A short discussion on the usefulness of the simulation tool is also included

  • 278.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lindberg, Bo
    Lens-Tech AB, Skellefteå, Sweden.
    Hjalmarsson, Anders
    Uppsala University, The Svedberg Laboratory.
    Modelling Cherenkov light from irradiated nuclear fuel assemblies using GEANT42010Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is currently used by International Atomic Energy Agency (IAEA) inspectors for gross defect verification of spent nuclear fuel assemblies in storage pools. A Cherenkov light image is obtained from the spent fuel and the verification is made by the detection of unique Cherenkov characteristics of spent fuel. To take further advantage of its quantitative capabilities, the DCVD’s ability to detect partial defects down to the 30% level is now being investigated.

    To evaluate the performance of the DCVD, simulations of the emitted and recorded light can be very useful. This presentation describes how the software toolkit GEANT4 is used to gain better understanding of the light contributions from the fuel and its environment by means of Monte Carlo simulations. The toolkit allows the user to access information on individual photon emission coordinates and their momentum vectors and it is also possible to take the expected rod-by-rod burnup distribution at different axial levels into account.

    Investigations have shown that the Cherenkov light production about the fuel is dominated by gamma radiation from the fuel material interacting with the water surrounding the fuel. A study of the range of the Cherenkov photon production from individual fuel rods, which is of relevance for partial-defect verification, is presented. In addition, emission distributions of Cherenkov light are presented for simulated PWR fuel assemblies with different configurations of replaced rods. Simulated light intensities in guide tubes are presented, showing variations depending on whether fuel rods nearby have been substituted or not.

  • 279.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sundkvist, Erik
    Parcey, Dennis
    Chen, Dennis
    Larsson, Mats
    Dahlberg, Joakim
    Axell, Kåre
    Lindberg, Bo
    Kosierb, Rick
    Partial defect verification using the DCVD: a capability evaluation approach2011Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a non-intrusive instrument available to theInternational Atomic Energy Agency (IAEA) for verifying spent nuclear fuel in storage pools. It iscurrently used for gross-defect evaluations, i.e. to verify that an item in a storage pool is anirradiated fuel assembly and not a fresh assembly or a dummy. This is done by recording images ofthe Cherenkov light emitted in the water surrounding the fuel. Currently, the instrument’s ability toalso detect partial defects at the 50% level or even lower is under study. Here, experimental work iscomplimented by modeling and simulations due to the limited availability of assemblies with partialdefects.Ideally, an IAEA inspector should be able to use the DCVD at e.g. a fuel storage site andimmediately after scanning obtain information on (1) whether an item is an irradiated fuel assemblyor not, and (2) whether the assembly is intact or suffers from a partial defect. This paper discusses adecision-making methodology intended for the latter purpose with the objective to implement it inthe DCVD software in order to facilitate smooth inspection procedures. Inspectors will thus not berequired to possess any expertise in the decision-making methodology.The paper also describes measurements performed during spring 2011 at the CLAB interim spentfuel storage in Sweden. The measurements were carried out with the objective to optimize theequipment handling and work flow during this type of measurement campaigns and to form a basisfor the evaluation of the DCVD’s ability to detect partial defects.

  • 280.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson Svärd, Staffan
    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.
    Students’ Approaches to Learning from Other Students’ Oral Presentations2015Conference paper (Other academic)
  • 281.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jonter, Thomas
    Stockholm University.
    Report on the 8th ESARDA course on nuclear safeguards and non-proliferation2011Conference paper (Other (popular science, discussion, etc.))
  • 282.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Persson, Karin
    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.
    Building a Strategy for ESARDA - Education, Training and Knowledge Management2015Conference paper (Other academic)
    Abstract [en]

    This document proposes a new strategy for how the ESARDA organization could work with education, training and knowledge management in nuclear safeguards. With this document we want to anchor these ideas within the organization and its management, in order to have a broad support for this initiative. We propose to activate all ESARDA working groups in the process of identifying, selecting and preparing material for module based education and training. ESARDA could then more effectively broaden its education and training activities and strengthen the connections with academia. In this way, we would also create a way to export knowledge on nuclear safeguards to nuclear education programs on the European level.

     

    We propose to create a task force that addresses a set of identified questions; examples are how to implement the new strategy, how to interact with academia and young professionals and how to develop, maintain, and structure the educational modules. By the end of 2015, the findings of the task force should be presented to the ESARDA management in order to be able to make a more informed decision on how to proceed with the new strategy.

  • 283.
    Grape, Sophie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svärd, Staffan Jacobsson
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lindberg, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Partial Defect Evaluation Methodology for Nuclear Safeguards Inspections of Used Nuclear Fuel Using the Digital Cherenkov Viewing Device2014In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 186, no 1, p. 90-98Article in journal (Refereed)
    Abstract [en]

    This paper describes possible ways of analyzing and interpreting data obtained using the digital Cherenkov viewing device on spent nuclear fuel assemblies for the identification of partial defects in the fuel. According to the terminology of the International Atomic Energy Agency, partial defects refer to items, for instance, fuel assemblies, that are manipulated to the extent that a fraction of the fuel material is diverted or substituted. Analysis can be performed either by using a measure of the total light intensity or by identifying the light distribution pattern emanating from the spent nuclear fuel, the goal of either type of analysis being a quantitative measure that can be used in the data interpretation step. Two possible data interpretation alternatives are presented here: the threshold method and the hypothesis testing method. This paper summarizes some of the simulation studies and results that have been obtained, related to the two analysis and data interpretation methodologies.

  • 284.
    Greczynski, G.
    et al.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden.;Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Mraz, S.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Hans, M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lu, J.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Hultman, L.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Schneider, J. M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation2017In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 17, article id 171907Article in journal (Refereed)
    Abstract [en]

    Modern applications of refractory ceramic thin films, predominantly as wear-protective coatings on cutting tools and on components utilized in automotive engines, require a combination of excellent mechanical properties, thermal stability, and oxidation resistance. Conventional design approaches for transition metal nitride coatings with improved thermal and chemical stability are based on alloying with Al. It is well known that the solubility of Al in NaCl-structure transition metal nitrides is limited. Hence, the great challenge is to increase the Al concentration substantially while avoiding precipitation of the thermodynamically favored wurtzite-AlN phase, which is detrimental to mechanical properties. Here, we use VAlN as a model system to illustrate a new concept for the synthesis of metastable single-phase NaCl-structure thin films with the Al content far beyond solubility limits obtained with conventional plasma processes. This supersaturation is achieved by separating the film-forming species in time and energy domains through synchronization of the 70-mu s-long pulsed substrate bias with intense periodic fluxes of energetic Al+ metal ions during reactive hybrid high power impulse magnetron sputtering of the Al target and direct current magnetron sputtering of the V target in the Ar/N-2 gas mixture. Hereby, Al is subplanted into the cubic VN grains formed by the continuous flux of low-energy V neutrals. We show that Al subplantation enables an unprecedented 42% increase in metastable Al solubility limit in V1-xAlxN, from x-0.52 obtained with the conventional method to 0.75. The elastic modulus is 325 +/- 5GPa, in excellent agreement with density functional theory calculations, and approximately 50% higher than for corresponding films grown by dc magnetron sputtering. The extension of the presented strategy to other Al-ion-assisted vapor deposition methods or materials systems is straightforward, which opens up the way for producing supersaturated single-phase functional ceramic alloy thin films combining excellent mechanical properties with high oxidation resistance.

  • 285.
    Greczynski, G.
    et al.
    Linkoping Univ, IFM, Dept Phys, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hultman, L.
    Linkoping Univ, IFM, Dept Phys, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Reference binding energies of transition metal carbides by core-level x-ray photoelectron spectroscopy free from Ar+ etching artefacts2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 436, p. 102-110Article in journal (Refereed)
    Abstract [en]

    We report x-ray photoelectron spectroscopy (XPS) core level binding energies (BE's) for the widely-applicable groups IVb-VIb transition metal carbides (TMCs) TiC, VC, CrC, ZrC, NbC, MoC, HfC, TaC, and WC. Thin film samples are grown in the same deposition system, by dc magnetron co-sputtering from graphite and respective elemental metal targets in Ar atmosphere. To remove surface contaminations resulting from exposure to air during sample transfer from the growth chamber into the XPS system, layers are either (i) Ar+ ion-etched or (ii) UHV-annealed in situ prior to XPS analyses. High resolution XPS spectra reveal that even gentle etching affects the shape of core level signals, as well as BE values, which are systematically offset by 0.2-0.5 eV towards lower BE. These destructive effects of Ar+ ion etch become more pronounced with increasing the metal atom mass due to an increasing carbon-to-metal sputter yield ratio. Systematic analysis reveals that for each row in the periodic table (3d, 4d, and 5d) C 1s BE increases from left to right indicative of a decreased charge transfer from TM to C atoms, hence bond weakening. Moreover, C 1s BE decreases linearly with increasing carbide/metal melting point ratio. Spectra reported here, acquired from a consistent set of samples in the same instrument, should serve as a reference for true deconvolution of complex XPS cases, including multinary carbides, nitrides, and carbonitrides.

  • 286.
    Greczynski, G.
    et al.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lu, J.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Hultman, L.
    Linkoping Univ, Dept Phys IFM, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Core-level spectra and binding energies of transition metal nitrides by non-destructive x-ray photoelectron spectroscopy through capping layers2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 396, p. 347-358Article in journal (Refereed)
    Abstract [en]

    We present the first measurements of x-ray photoelectron spectroscopy (XPS) core level binding energies (BE: s) for the widely-applicable group IVb-VIb polycrystalline transition metal nitrides (TMN's) TiN, VN, CrN, ZrN, NbN, MoN, HfN, TaN, and WN as well as AlN and SiN, which are common components in the TMN-based alloy systems. Nitride thin film samples were grown at 400.degrees C by reactive dc magnetron sputtering from elemental targets in Ar/ N-2 atmosphere. For XPS measurements, layers are either (i) Ar+ ion-etched to remove surface oxides resulting from the air exposure during sample transfer from the growth chamber into the XPS system, or (ii) in situ capped with a few nm thick Cr or W overlayers in the deposition system prior to air-exposure and loading into the XPS instrument. Film elemental composition and phase content is thoroughly characterized with time-of-flight elastic recoil detection analysis (ToF(-) ERDA), Rutherford backscattering spectrometry (RBS), and x-ray diffraction. High energy resolution core level XPS spectra acquired with monochromatic Al K alpha radiation on the ISO-calibrated instrument reveal that even mild etching conditions result in the formation of a nitrogen-deficient surface layer that substantially affects the extracted binding energy values. These spectra-modifying effects of Ar+ ion bombardment increase with increasing the metal atom mass due to an increasing nitrogen-to-metal sputter yield ratio. The superior quality of the XPS spectra obtained in a non-destructive way from capped TMN films is evident from that numerous metal peaks, including Ti 2p, V 2p, Zr 3d, and Hf 4f, exhibit pronounced satellite features, in agreement with previously published spectra from layers grown and analyzed in situ. In addition, the N/ metal concentration ratios are found to be 25-90% higher than those obtained from the corresponding ion-etched surfaces, and in most cases agree very well with the RBS and ToF-E ERDA values. The N 1 s BE: s extracted from capped TMN films, thus characteristic of a native surface, show a systematic trend, which contrasts with the large BE spread of literature "reference" values. Hence, non-destructive core level XPS employing capping layers provides an opportunity to obtain high-quality spectra, characteristic of virgin in situ grown and analyzed TMN films, although with larger versatility, and allows for extracting core level BE values that are more reliable than those obtained from sputter-cleaned N-deficient surfaces. Results presented here, recorded from a consistent set of binary TMN's grown under the same conditions and analyzed in the same instrument, provide a useful reference for future XPS studies of multinary materials systems allowing for true deconvolution of complex core level spectra.

  • 287.
    Griffin, Peter J.
    et al.
    Sandia National Laboratories, Albuquerque, NM, USA.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simakov, Stanislav
    Karlsruhe Institute of Technology, Karlsruhe, Germany.
    Nuclear Reaction Data and Uncertainties for Radiation Damage: Summary Report of the Technical Meeting, IAEA Headquarters, Vienna, Austria13 – 16 June 20162016Report (Other academic)
    Abstract [en]

    This Meeting was organized to implement the recommendation of the second Research Coordinated Meeting (RCM) of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) “Primary Radiation Damage Cross Sections” to analyse the accuracy and consistency of the radiation damage-relevant nuclear data in the major nuclear data evaluations with the eventual goal of identifying the most reliable data and provide quantitative uncertainty estimates. Participants have considered the status of the primary nuclear data, such as recoils spectra in the latest releases of ENDF, JEFF, JENDL, FENDL, ROSFOND and TENDL, the ways of deriving the damage quantities KERMA, NRT- or arc-dpa and gas production cross sections as well as the recipes for an assessment of their uncertainties. This report contains the contemporary view of the Meeting participants on these issues in the form of a consolidated set of statements, recommendations and individual summaries.

  • 288.
    Grogan, B.
    et al.
    Oak Ridge National Laboratory, USA.
    Favalli, Andrea
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Liljenfeldt, Henrik
    Oak Ridge National Laboratory, Oak Ridge, TN, USA.
    Mozin, Vladimir
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Schwalbach, Peter
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Sjöland, Anders
    Swedish Nuclear Fuel and Waste Management Company.
    Tobin, Stephen
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Trellue, Holly
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    Vaccaro, Stefano
    European Commission, DG Energy, Euratom Safeguards Luxemburg, Luxemburg.
    Vo, Duc
    Los Alamos National Laboratory, Los Alamos, NM, USA.
    NDA Measurement Analysis of Spent Nuclear Fuel Assemblies at the SwedishClab Facility Using the INDEPTH Code2016Conference paper (Other academic)
    Abstract [en]

    A project to research the application of non-destructive assay (NDA) to spent fuel assemblies is underwayamong a team comprised of the European Commission, DG Energy, Directorate Safeguards; the SwedishNuclear Fuel and Waste Management Company; Uppsala University; and US national laboratories (LosAlamos National Laboratory, Lawrence Livermore National Laboratory, and Oak Ride NationalLaboratory). The research goals of this project combine safeguards goals (detection of missing/substitutedfuel pins and verification of operator declarations) and non-safeguards goals (estimation of decay heat andreactivity of each assembly). The final objective of this project is to quantify the capability of severalintegrated NDA instruments being developed to meet the aforementioned safeguards and non-safeguardsgoals using combined signatures of neutron, gamma-ray, and decay heat.

    In support of these goals, passive gamma and neutron measurements were made on 50 spent fuelassemblies at the Swedish Central Interim Storage Facility for Spent Nuclear Fuel (Clab) using high-purity germanium and Fork detectors. The Oak Ridge National Laboratory (ORNL) Inverse DepletionTheory (INDEPTH) code was used to reconstruct the spent fuel parameters (initial enrichment, burnup,and cooling time) for each assembly. INDEPTH uses a gradient-based search technique—combined withthe ORIGEN code for forward depletion calculations—to find the spent fuel parameters that result inpassive gamma and neutron outputs that best match the measurements. The results of the INDEPTHcalculations are presented and compared to the operator declarations (trusted in this case) in order toassess how accurately these parameters can be determined using current passive gamma and neutronmeasurements. These results will provide a baseline which can be used to assess whether and by howmuch new safeguards instruments being developed for NDA measurements can improve the accuracy ofreconstructed fuel parameter values.

  • 289.
    Gustavsson, Cecilia
    et al.
    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.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Öhrn, Angelica
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Inelastic neutron scattering from carbon, iron, yttrium and lead2012In: CNR*11: Third International Workshop on Compound Nuclear Reactions and Related Topics / [ed] Krticka, M; Becvar, F; Kroll, J, 2012, Vol. 21, p. 03004-Conference paper (Refereed)
    Abstract [en]

    Double-differential cross sections and angular distributions of inelastic neutron scattering on C-12, Fe-56, Y-89 and Pb-208 have been measured at 96 MeV at The Svedberg Laboratory, Uppsala, Sweden. Results on elastic neutron scattering at 96 MeV from these nuclei have been reported previously [1-3]. To obtain the inelastic cross sections, a forward-folding technique has been applied. A physically reasonable trial spectrum has been folded with the response function of the detector system and the output has been compared with the experimental data. To create the trial spectrum, a Gaussian has been used for the elastic part and the PRECO code [4-7] for the inelastic part. Other models were tested for the pre-equilibrium contribution and the method was found to be model independent. The response function of the detector setup has been obtained experimentally at the smallest possible angle, in this case at 9 deg. The resulting preliminary inelastic scattering data cover an excitation energy range up to 45 MeV and the angular intervals 28 to 58 degrees for C-12, 26 to 65 degrees for Fe-56 and 26 to 52 degrees for Y-89 and Pb-208. The preliminary results are discussed and compared to several model codes as well as existing experimental data for (n,n'x), (n,p'x) and (p,p'x). Possible improvements of the analysis are also discussed.

  • 290.
    Gustavsson, Cecilia
    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.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ohrn, A.
    Blomgren, J.
    Tippawan, U.
    Status Report on the Analysis of Inelastic Neutron Scattering from Carbon, Iron, Yttrium and Lead at 96 MeV2014In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 119, p. 183-185Article in journal (Refereed)
    Abstract [en]

    This work is part of an effort to provide more experimental data for the (n,n'x) reaction. The experiments were carried out at The Svedberg Laboratory in Uppsala, Sweden, at the quasi-monoenergetic neutron beam of 96 MeV, before the facility was upgraded in 2004. Using an extended data analysis of data primarily intended for measuring elastic neutron scattering only, it was found to be possible to extract information on the inelastic scattering from several nuclei. In the preliminary data analysis, an iterative forward-folding technique was applied, in which a physically reasonable trial spectrum was folded with the response function of the detector system and the output was compared to the experimental data. As a result, double-differential cross sections and angular distributions of inelastic neutron scattering from C-12, Fe-56, Y-89 and Pb-208 could be obtained. In this paper, a status update on the efforts to improve the description of the detector response function is given.

  • 291.
    Gustavsson, Cecilia
    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.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Öhrn, Angelica
    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.
    Tippawan, Udomrat
    Status report on the analysis of inelastic neutron scattering from carbon, iron, yttrium and lead at 96 MeV2014Conference paper (Refereed)
  • 292.
    Gustavsson, Cecilia
    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.
    Scian, Giovanni
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Lecolley, F-R
    Tippawan, U
    Watanabe, Y
    Nuclear data measurements at the new NFS facility at GANIL2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 2012, no T150, p. 014017-Article in journal (Refereed)
    Abstract [en]

    The NFS (Neutrons For Science) facility is part of the SPRIAL 2 project at GANIL, Caen, France. The facility is currently under construction and the first beam is expected in early 2013. NFS will have a white neutron source covering the 1–40 MeV energy range with a neutron flux higher than comparable facilities. A quasi-mono-energetic neutron beam will also be available. In these energy ranges, especially above 14 MeV, there is a large demand for neutron-induced data for a wide range of applications involving dosimetry, medical therapy, single-event upsets in electronics and nuclear energy. Today, there are a few or no cross section data on reactions such as (n, fission), (n, xn), (n, p), (n, d) and (n, α ). We propose to install experimental equipment for measuring neutron-induced light-charged particle production and fission relative to the H(n, p) cross section. Both the H(n, p) cross section and the fission cross section for 238 U are important reference cross sections used as standards for many other experiments. Nuclear data for certain key elements, such as closed shell nuclei, are also of relevance for the development of nuclear reaction models. Our primary intention is to measure charged particle production (protons, deuterons and alphas) from 12 C, 16 O, 28 Si and 56 Fe and neutron-induced fission cross sections from 238 U and 232 Th.

  • 293.
    Gustavsson, Cecilia
    et al.
    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.
    Andersson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Physics Didactics.
    Engineering physics students' conceptions of entropy2013In: 4:e UTVECKLINGSKONFERENSEN FÖR SVERIGES INGENJÖRSUTBILDNINGAR, Umeå: Tekniska högskolan, Umeå universitet , 2013, p. 57-59Conference paper (Refereed)
  • 294.
    Göttsche, M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tippawan, Udomrat
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Pernilla
    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.
    Gustavsson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Österlund, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Simutkin, Vasily
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    C/O Kerma coefficient ratio for 96 MeV neutrons deduced from microscopic measurements2010In: Radiation Measurements, ISSN 1350-4487, E-ISSN 1879-0925, Vol. 45, no 10, p. 1139-1141Article in journal (Refereed)
    Abstract [en]

    Double-differential cross sections for neutron-induced light-ion production at 96 MeV have been measured for a variety of nuclei at The Svedberg Laboratory. Using the measured cross-section data, we deduce the Kerma coefficient from carbon and oxygen for p, d, t, He-3 and alpha particles. In order to get the total Kerma for C and O, we add GNASH calculation values where experimental data are not available and obtain a Kerma coefficient of 7.85 +/- 0.63 fGy m(2) for carbon and 7.09 +/- 0.57 fGy m(2) for oxygen. The C/O Kerma coefficient ratio then becomes 1.11 +/- 0.11. In addition we determine the Kerma ratio between ICRU muscle and A-150, again adding calculations with the GNASH code where no experimental data are available, and obtain a value of 0.98 +/- 0.05. While the Kerma coefficients for carbon and oxygen do not agree with the prediction in ICRU Report 63, the ratio values are in good agreement with existing predictions.

  • 295.
    Haglund, Jesper
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Physics Didactics.
    Melander, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Physics Didactics.
    University physics students’ ideas of thermal radiation expressed in open laboratory activities using infrared cameras2017In: Research in Science & Technological Education, ISSN 0263-5143, E-ISSN 1470-1138, Vol. 35, no 3, p. 349-367Article in journal (Refereed)
    Abstract [en]

    Background

    University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation or a heat pump. Students had access to handheld infrared (IR) cameras for their investigations.

    Purpose

    The purpose of the research was to explore students’ interactions with reformed thermodynamics laboratory activities. It was guided by the research question: How do university physics students make use of IR cameras in the investigation of the interaction of thermal radiation?

    Sample

    The study was conducted with a class of first-year university physics students in Sweden. The interaction with the activities of four of the students was selected for analysis. The four students are males.

    Design and methods

    We used a qualitative, interpretive approach to the study of students’ interaction.  The primary means of data collection was video recording of students’ work with the laboratory activities and their subsequent presentations. The analysis focused on how IR cameras helped students notice phenomena relating to thermal radiation, with comparison to previous research on students’ conceptions of thermal radiation.

    Results

    When using the IR camera students attended to the reflection of thermal radiation on shiny surfaces, such as polished metals, windows or a white-board, and emissive properties of surfaces of different types. In this way, they went beyond using the technology as a temperature probe. Students were able to discuss merits and shortcomings of IR cameras in comparison with digital thermometers.

    Conclusions

    With the help of IR cameras, university physics students attend to thermal phenomena that would otherwise easily go unnoticed.

  • 296. Hambsch, F. -J
    et al.
    Gamboni, T.
    EC JRC, Directorate Nucl Safety & Secur DN2S, B-2440 Geel, Belgium.
    Geerts, W.
    EC JRC, Directorate Nucl Safety & Secur DN2S, B-2440 Geel, Belgium.
    Gook, A.
    EC JRC, Directorate Nucl Safety & Secur DN2S, B-2440 Geel, Belgium.
    Oberstedt, S.
    EC JRC, Directorate Nucl Safety & Secur DN2S, B-2440 Geel, Belgium.
    Vidali, M.
    EC JRC, Directorate Nucl Safety & Secur DN2S, B-2440 Geel, Belgium.
    Al-Adili, Ali
    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.
    Pomp, Stephan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prompt Neutron Emission Correlations with Fission Fragment Properties2018In: Fission And Properties Of Neutron-Rich Nuclei: Proceedings of the Sixth International Conference on ICFN6 / [ed] Hamilton, JH Ramayya, AV Talou, P, World Scientific, 2018, p. 503-512Conference paper (Refereed)
    Abstract [en]

    The investigation of the dynamics of the nuclear fission process has been a standing research topic at the JRC-Geel during the past decades. Recently the focus was put on the de-excitation of fission fragments through the emission of prompt neutrons and gamma-rays. To this end new detector systems were developed at JRC-Geel, e.g. a position sensitive ionization chamber used in conjunction with the neutron scintillator array SCINTIA. The array has been tested using the spontaneous fission of Cf-252. The goal is to study correlations of fission fragments with prompt neutron emission in the resolved resonance region. No strong fluctuations of the average prompt neutron multiplicity for the strongest resonances in U-235 were observed. From the present data the mass-dependent neutron multiplicity, v(A), was generated. The v(A) distribution shows a more pronounced dip around the doubly magic mass A = 132 and at very low masses around A similar to 80 compared to the literature. In addition, a steeper slope for v(TKE) is observed. Cross checking with fragment data clearly shows a narrower mass and total kinetic energy (TKE) distribution. The 2E-2v spectrometer VERDI (VElocity foR Direct mass Identification) became operational. For Cf-252(sf) superior mass resolution is observed compared to a twin Frisch-grid ionization chamber. For post-neutron mass distributions still some issues need to be solved and v(A), being the difference of pre- and post-neutron mass distributions, is still deviating from literature data. Eventually, VERDI will provide a complementary measurement technique to assess v(A) and v(TKE). In addition, an experimental campaign to measure v(A) as a function of incident neutron energy for different actinides has been started. First tests show promising results.

  • 297. Hambsch, F. -J
    et al.
    Oberstedt, S.
    Al-Adili, Ali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Brys, T.
    Billnert, R.
    Matei, C.
    Oberstedt, A.
    Salvador-Castineira, P.
    Tudora, A.
    Vidali, M.
    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. 38-41Article 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.

  • 298.
    Hambsch, Franz-Josef
    et al.
    IRMM-JRC-EC.
    Göök, Alf
    IRMM-JRC-EC.
    Oberstedt, Stephan
    IRMM-JRC-EC.
    Vidali, Marzio
    IRMM-JRC-EC.
    Al-Adili, Ali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tarrío, Diego
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Solders, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jansson, Kaj
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Rakopoulos, Vasileios
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Stephan, Pomp
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Prompt fission neutron emission from 235U(n,f): thermal and resonance region2015In: Conference: 14th International Conference on Nuclear Reaction Mechanisms - CERN-Proceedings-2015-001, At Villa Monastero, Varenna, Italy / [ed] F. Cerutti, 2015Conference paper (Refereed)
    Abstract [en]

    For nuclear modelling and improved evaluation of nuclear data, knowledge of fluctuations of the prompt neutron multiplicity as a function of incident neutron energy is requested for the major actinides 235U and 239Pu. Experimental investigations of the prompt fission neutron emission in resonance-neutron induced fission on 235U are taking place at the GELINA facility of the IRMM. The experiment employs an array of scintillation detectors (SCINTIA) in conjunction with a newly designed 3D position-sensitive twin Frisch-grid ionization chamber. In addition, the mass-dependent prompt neutron multiplicity, (A), has attracted particular attention. Recent, sophisticated nuclear fission models predict that the additional excitation energy, brought into the fission system at higher incident neutron energies, leads to an increased neutron multiplicity only for heavy fragments, as observed in the 237Np(n,f) reaction. A first feasibility study has been performed at the JRC-IRMM VdG accelerator to measure nu(A) for 235U(n,f).

  • 299. Hans, M.
    et al.
    Baben, M. To
    Music, D.
    Ebenhoech, J.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kurapov, D.
    Arndt, M.
    Rudigier, H.
    Schneider, J. M.
    Effect of oxygen incorporation on the structure and elasticity of Ti-Al-O-N coatings synthesized by cathodic arc and high power pulsed magnetron sputtering2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 9, p. 093515-Article in journal (Refereed)
    Abstract [en]

    Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young's moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds.

  • 300.
    Hans, Marcus
    et al.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Baben, Moritz To
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany.;GTT Technol, Kaiserstr 103, D-52134 Herzogenrath, Germany..
    Chen, Yen-Ting
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Pradeep, Konda G.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Holzapfel, Damian M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kurapov, Denis
    Oerlikon Surface Solut AG, Oerlikon Balzers, Iramali 18, LI-9496 Balzers, Liechtenstein..
    Ramm, Juergen
    Oerlikon Surface Solut AG, Oerlikon Balzers, Iramali 18, LI-9496 Balzers, Liechtenstein..
    Arndt, Mirjam
    Oerlikon Surface Solut AG, Oerlikon Balzers, Iramali 18, LI-9496 Balzers, Liechtenstein..
    Rudigier, Helmut
    Oerlikon Surface Solut AG, Oerlikon Balzers, Churer Str 120, CH-8808 Pfaffikon, Switzerland..
    Schneider, Jochen M.
    Rhein Westfal TH Aachen, Mat Chem, Kopernikusstr 10, D-52074 Aachen, Germany..
    Substrate rotation-induced chemical modulation in Ti-Al-O-N coatings synthesized by cathodic arc in an industrial deposition plant2016In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 305, p. 249-253Article in journal (Refereed)
    Abstract [en]

    Reactive cathodic arc evaporation of Ti-Al-O-N was carried out in an industrial deposition system with two-fold substrate rotation. The structural and compositional evolution of the coatings was studied by combining scanning transmission electron microscopy and 3D atom probe tomography (APT). The formation of alternating O- and N-rich sublayers was identified by APT and can be understood by considering the substrate rotation induced variation in plasma density and fluxes of film-forming species. The effect of plasma density and fluxes on the incorporation of reactive species was studied in stationary deposition experiments and preferred N incorporation occurs, when the growing coating surface is facing the arc source. Thus, the growing surface is positioned in a region of high plasma density characterized by large fluxes of film forming-species. Preferred O incorporation takes place in a region of low plasma density where small fluxes are present, when the growing surface is blocked from the arc source by the substrate holder. Hence, compositional modulations are caused by substrate rotation as the growing coating surface is periodically exposed to regions of high plasma density and large fluxes of film-forming species and regions of low plasma density and small fluxes. These findings are highly relevant for all reactive industrial plasma assisted physical vapor deposition processes utilizing substrate rotation.

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