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  • 151.
    Branger, Erik
    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.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wernersson, Erik L. G.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Towards unattended partial-defect verification of irradiated nuclear fuel assemblies using the DCVD2014Conference paper (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a tool used by authority inspectors to verify irradiated nuclear fuel assemblies in wet storage by measuring the Cherenkov light emitted. The DCVD is approved by the IAEA for gross defect verification, and is one of the few inspection tools approved for partial defect verification.

    There is interest in adapting the DCVD to work in unattended mode, so that it can be used to verify large quantities of irradiated fuel assemblies prior to moving them to difficult-to-access storage locations. This work presents methods based on image analysis that can be used to reduce the effects of different types of distortions encountered when performing measurements with the DCVD. Implementing these methods will ensure that data of high quality is obtained. Verification prior to moving fuels to difficult-to-access storage may also require a dedicated measurement station to be built, and it is argued that by constructing these stations with the DCVD in mind, many distortions can be reduced or eliminated. Thus, by implementing safeguards-by-design, it is possible to ensure that the DCVD is used in near optimal conditions.

  • 152.
    Branger, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wernersson, Erik L. G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan Svärd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Image analysis as a tool for improved use of the Digital Cherenkov Viewing Device for inspection of irradiated PWR fuel assemblies.2014Report (Other academic)
    Abstract [en]

    The Digital Cherenkov Viewing Device (DCVD) is a tool used to measure the Cherenkov light emitted from irradiated nuclear fuel assemblies stored in water pools. It has been approved by the IAEA for attended gross defect verification, as well as for partial defect verification, where a fraction of the fuel material has been diverted. In this report, we have investigated the current procedures for recording images with the DCVD, and have looked into ways to improve these procedures. Using three different image sets of PWR fuel assemblies, we have analysed what information and results can be obtained using image analysis techniques. We have investigated several error sources that distort the images, and have shown how these errors affect the images. We have also described some of the errors mathematically, and have discussed how these error sources may be compensated for, if the character and magnitude of the errors are known. Resulting from our investigations are a few suggestions on how to improve the procedures and consequently the quality of the images recorded with the DCVD as well as suggestions on how to improve the analysis of collected images. Specifically, a few improvements that should be looked into in the short term are:

    • Images should be recorded with the fuel assembly perfectly centered in the image, and preferably without any tilt of the DCVD relative to the fuel in order to obtain accurate measurements of the light intensity. Image analysis procedures that may aid the alignment are presented.

    • To compensate for the distorting effect of the water surface and possible turbulence in the water, several images with short exposure time should be captured rather than one image with long exposure time. Using image analysis procedures, it is possible to sum the images resulting in a final image with less distortions and improved quality.

    • A reference image should be used to estimate device-related distortions, so that these distortions are compensated for. Ideally, this procedure can also be used to calibrate individual pixels.

    • The background should be carefully taken into account in order to separate the background level from diffuse signal components, allowing for the background to be subtracted. Accordingly, each measurement campaign should be accompanied by at least one background measurement, recorded from a section in the storage pool where no fuel assemblies are present. Furthermore, the background level should be determined from a larger region in the image and not from one individual pixel, as is currently done.

    • A database of measurements should be set up, containing DCVD images, information about the applied DCVD settings and the conditions that the DCVD was used in. Any partial defect verification procedure at any time could then be tested against as much data as possible. Accordingly, a database can aid in evaluating and improving partial defect verification methods using DCVD image analysis.

    Based on the findings and discussions in this report, some long-term improvements are also suggested.

  • 153.
    Bruckner, Barbara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Bauer, Peter
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    The impact of surface oxidation on energy spectra of keV ions scattered from transition metals2019In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 479, p. 1287-1292Article in journal (Refereed)
    Abstract [en]

    Studying the initial stages of surface oxidation is of great relevance to understand how oxygen alters the physical and chemical properties at the interface of the host material to the environment and is therefore, crucial for improvement in manifold technological applications. We investigated the influence of surface oxygen on ion spectra recorded for keV noble gas ions backscattered from metal surfaces in low energy ion scattering (LEIS). Initially pure Zn and Ta surfaces, chosen for their well-characterized properties in ion-neutralization in LEIS, have been oxidized and ion spectra for pure and oxidized surfaces have been compared. Oxygen on the surface significantly influences shape and intensity of the backscattered ion spectrum at all energies: for both metal systems, the surface scattered ion yield of the metal is drastically decreasing under oxygen presence. The observed decrease, however, cannot be explained by the reduction in the surface areal density of the metal constituents exclusively. At least for Zn an additional significant change in charge exchange behavior is necessary to explain the observations. In contrast to the generally observed decrease in the yield of ions scattered from the outermost surface, the change in shape and intensity of the reionization background are found to show opposing trends and different energy dependencies for Zn and Ta.

  • 154.
    Bruckner, Barbara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Roth, D.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Goebl, D.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Bauer, P.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    A note on extracting electronic stopping from energy spectra of backscattered slow ions applying Bragg's rule2018In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 423, p. 82-86Article in journal (Refereed)
    Abstract [en]

    Electronic stopping measurements in chemically reactive targets, e.g., transition and rare earth metals are challenging. These metals often contain low Z impurities, which contribute to electronic stopping. In this article, we present two ways how one can correct for the presence of impurities in the evaluation of proton and He stopping in Ni for primary energies between 1 and 100 keV, either considering or ignoring the contribution of the low Z impurities to multiple scattering. We find, that for protons either method leads to concordant results, but for heavier projectiles, e.g. He ions, the influence on multiple scattering must not be neglected.

  • 155.
    Bydell, Linn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Evaluation of the thermal-hydraulic software GOTHIC for nuclear safety analyses2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this master theses was to evaluate the thermal-hydraulic calculation software GOTHIC for the purpose of nuclear containment safety analyses. The evaluation was performed against some of the Marviken full scale containment experiments and a comparison was also made against the two codes RELAP5 and COPTA. Models with different complexity were developed in GOTHIC and the parameters pressure, temperature and energy in different areas of the enclosure was investigated.

    The GOTHIC simulations in general showed a good agreement with the Marviken experimental results and had an overall better agreement then RELAP5. From the results it was possible to conclude that the developed GOTHIC model provided a good representation of the Marviken facility. 

  • 156.
    Bykov, I.
    et al.
    Royal Inst Technol KTH, Div Fus Plasma Phys, Stockholm, Sweden..
    Bergsåker, H.
    Royal Inst Technol KTH, Div Fus Plasma Phys, Stockholm, Sweden..
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Zhou, Y.
    Royal Inst Technol KTH, Div Fus Plasma Phys, Stockholm, Sweden..
    Heinola, K.
    Univ Helsinki, Dept Phys, POB 64, Helsinki 00560, Finland..
    Pettersson, Jean
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Likonen, J.
    VTT, POB 1000, Espoo 02044, Finland..
    Petersson, P.
    Royal Inst Technol KTH, Div Fus Plasma Phys, Stockholm, Sweden..
    Widdowson, A.
    EUROfus Consortium, JET, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Studies of Be migration in the JET tokamak using AMS with Be-10 marker2016Conference paper (Refereed)
    Abstract [en]

    The JET tokamak is operated with beryllium limiter tiles in the main chamber and tungsten coated carbon fiber composite tiles and solid W tiles in the divertor. One important issue is how wall materials are migrating during plasma operation. To study beryllium redistribution in the main chamber and in the divertor, a Be-10 enriched limiter tile was installed prior to plasma operations in 2011-2012. Methods to take surface samples have been developed, an abrasive method for bulk Be tiles in the main chamber, which permits reuse of the tiles, and leaching with hot HCl to remove all Be deposited at W coated surfaces in the divertor. Quantitative analysis of the total amount of Be in cm(2) sized samples was made with inductively coupled plasma atomic emission spectroscopy (ICP-AES). The Be-10/Be-9 ratio in the samples was measured with accelerator mass spectrometry (AMS). The experimental setup and methods are described in detail, including sample preparation, measures to eliminate contributions in AMS from the B-10 isobar, possible activation due to plasma generated neutrons and effects of diffusive isotope mixing. For the first time marker concentrations are measured in the divertor deposits. They are in the range 0.4-1.2% of the source concentration, with moderate poloidal variation.

  • 157.
    Caldeira Balkeståhl, Li
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Elter, Zsolt
    Grape, Sophie
    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.
    Application of Multivariate Analysis to Gamma and Neutron Signatures from Spent Nuclear Fuel2018Conference paper (Other academic)
  • 158.
    Caldeira Balkeståhl, Li
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Elter, Zsolt
    Grape, Sophie
    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.
    MCNP simulations of prototype DDSI detector2018Conference paper (Other academic)
  • 159.
    Caldeira Balkeståhl, Li
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Elter, Zsolt
    Grape, Sophie
    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.
    Nuclear safeguards verification of modelled partial defect PWR fuel using multivariate analysis2018Conference paper (Other academic)
  • 160.
    Carlson, A. D.
    et al.
    NIST, 100 Bur Dr,Stop 8463, Gaithersburg, MD 20899 USA..
    Pronyaev, V. G.
    State Corp Rosatom, PI Atomstandart, Moscow 117342, Russia..
    Capote, R.
    NAPC, Int Atom Energy Agcy, Nucl Data Sect, Vienna, Austria..
    Hale, G. M.
    Los Alamos Natl Lab, Los Alamos, NM 87545 USA..
    Chen, Z. -P
    Duran, I.
    Univ Santiago de Compostela, Santiago De Compostela, Spain..
    Hambsch, F. -J
    Kunieda, S.
    Japan Atom Energy Agcy, Nucl Data Ctr, Tokai, Ibaraki 3191195, Japan..
    Mannhart, W.
    Phys Tech Bundesanstalt, Org 6-4, D-38116 Braunschweig, Germany..
    Marcinkevicius, Benjaminas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. NAPC, Int Atom Energy Agcy, Nucl Data Sect, Vienna, Austria..
    Nelson, R. O.
    Los Alamos Natl Lab, Los Alamos, NM 87545 USA..
    Neudecker, D.
    Los Alamos Natl Lab, Los Alamos, NM 87545 USA..
    Noguere, G.
    CEA Cadarache, LEPh, SPRC, F-13108 St Paul Les Durance, France..
    Paris, M.
    Los Alamos Natl Lab, Los Alamos, NM 87545 USA..
    Simakov, S. P.
    Karlsruhe Inst Technol, Hermann von Helmholtz Pl 1, D-76344 Eggenstein Leopoldshafen, Germany..
    Schillebeeckx, P.
    EC JRC Directorate G, Unit G-2, B-2440 Geel, Belgium..
    Smith, D. L.
    Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA..
    Tao, X.
    China Inst Atom Energy, CNDC, Beijing, Peoples R China..
    Trkov, A.
    NAPC, Int Atom Energy Agcy, Nucl Data Sect, Vienna, Austria..
    Wallner, A.
    Univ Vienna, Fac Phys, Vera Lab, A-1090 Vienna, Austria.;Australian Natl Univ, Dept Nucl Phys, Canberra, ACT 0200, Australia..
    Wang, W.
    China Inst Atom Energy, CNDC, Beijing, Peoples R China..
    Evaluation of the Neutron Data Standards2018In: Nuclear Data Sheets, ISSN 0090-3752, E-ISSN 1095-9904, Vol. 148, p. 143-188Article in journal (Refereed)
    Abstract [en]

    With the need for improving existing nuclear data evaluations, (e.g., ENDF/B-VIII.0 and JEFF-3.3 releases) the first step was to evaluate the standards for use in such a library. This new standards evaluation made use of improved experimental data and some developments in the methodology of analysis and evaluation. In addition to the work on the traditional standards, this work produced the extension of some energy ranges and includes new reactions that are called reference cross sections. Since the effort extends beyond the traditional standards, it is called the neutron data standards evaluation. This international effort has produced new evaluations of the following cross section standards: the H(n,n), Li-6(n,t), B-10(n, alpha), B-10(n,alpha(1)gamma), C-nat(n,n), Au(n,gamma), U-235(n,f) and U-238(n,f). Also in the evaluation process the U-238(n,gamma) and Pu-239(n,f) cross sections that are not standards were evaluated. Evaluations were also obtained for data that are not traditional standards: the Maxwellian spectrum averaged cross section for the Au(n,gamma) cross section at 30 keV; reference cross sections for prompt gamma-ray production in fast neutron-induced reactions; reference cross sections for very high energy fission cross sections; the Cf-252 spontaneous fission neutron spectrum and the U-235 prompt fission neutron spectrum induced by thermal incident neutrons; and the thermal neutron constants. The data and covariance matrices of the uncertainties were obtained directly from the evaluation procedure.

  • 161.
    Carlson, A. D.
    et al.
    NIST, Gaithersburg, MD USA.
    Pronyaev, V.
    Rosatom State Corp, Atomsrandart, Moscow, Russia.
    Hale, G. M.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Zhenpeng, C.
    Tsinghua Univ, Beijing, Peoples R China.
    Capote, R.
    IAEA, NAPC Nucl Data Sect, Vienna, Austria.
    Duran, I.
    Univ Santiago de Compostela, Fac Fis, La Coruna, Spain.
    Hambsch, F. -J
    EC JRC Dir G, Geel, Belgium.
    Kawano, T.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Kunieda, S.
    Japan Atom Energy Agcy, Nucl Data Ctr, Tokai, Ibaraki, Japan.
    Mannhart, W.
    Phys Tech Bundesanstalt, Neutron Metrol Grp, Braunschweig, Germany.
    Marcinkevicius, Benjaminas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. IAEA, NAPC Nucl Data Sect, Vienna, Austria.
    Nelson, R. O.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Neudecker, D.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Noguere, G.
    CEA Cadarache, SPRC/LEPh, St Paul Les Durance, France.
    Paris, M.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Schillebeeckx, P.
    EC JRC Dir G, Unit G2, Geel, Belgium.
    Simakov, S.
    IAEA, NAPC Nucl Data Sect, Vienna, Austria; Karlsruhe Inst Technol, Eggenstein Leopoldshafen, Germany.
    Smith, D. L.
    Argonne Associate Seville, Coronado, CA USA.
    Talou, P.
    Los Alamos Natl Lab, Los Alamos, NM USA.
    Tao, X.
    China Inst Atom Energy, CNDC, Beijing, Peoples R China.
    Trkov, A.
    IAEA, NAPC Nucl Data Sect, Vienna, Austria.
    Wallner, A.
    Australian Natl Univ, Res Sch Phys & Engn, Nucl Phys, Canberra, ACT, Australia.
    A new evaluation of the neutron data standards2017In: ND 2016: INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY / [ed] Plompen, A Hambsch, FJ Schillebeeckx, P Mondelaers, W Heyse, J Kopecky, S Siegler, P Oberstedt, S, EDP Sciences, 2017, article id 02025Conference paper (Refereed)
    Abstract [en]

    Evaluations are being done for the H(n,n), 6Li(n,t), 10B(n,αγ), 10B(n,α), C(n,n), Au(n,γ), 235U(n,f) and 238U(n,f) standard cross sections. Evaluations are also being done for data that are not traditional standards including: the Au(n,γ) cross section at energies below where it is considered a standard; reference cross sections for prompt gamma-ray production in fast neutron-induced reactions; reference cross sections for very high energy fission cross sections; the 235U thermal neutron fission spectrum and the 252Cf spontaneous fission neutron spectrum and the thermal constants.

  • 162.
    Carlson, Allan D.
    et al.
    Natl Inst Stand & Technol, 100 Bur Dr, Gaithersburg, MD 20899 USA.
    Pronyaev, Vladimir G.
    Rosatom State Corp, Atomsrandart, Moscow, Russia.
    Capote, Roberto
    IAEA, NAPC Nucl Data Sect, Vienna, Austria.
    Hale, Gerald M.
    Los Alamos Natl Lab, Los Alamos, NM 87544 USA.
    Duran, Ignacio
    Univ Santiago de Compostela, Santiago De Compostela, Spain.
    Hambsch, Franz-Josef
    EC JRC Directorate G, Unit G2, Geel, Belgium.
    Kunieda, Satoshi
    Japan Atom Energy Agcy, Nucl Data Ctr, Ibaraki, Japan.
    Mannhart, Wolf
    Phys Tech Bundesanstalt, Neutron Metrol Grp, Braunschweig, Germany.
    Marcinkevicius, Benjaminas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Nelson, Ronald O.
    Los Alamos Natl Lab, Los Alamos, NM 87544 USA.
    Noguere, Gilles
    CEA Cadarache, SPRC LEPh, St Paul Les Durance, France.
    Schillebeeckx, Peter
    EC JRC Directorate G, Unit G2, Geel, Belgium.
    Simakov, Stanislav
    Karlsruhe Inst Technol, Hermann von Helmholtz Pl 1, D-76344 Eggenstein Leopoldshafen, Germany.
    Tao, Xi
    China Inst Atom Energy, CNDC, Beijing, Peoples R China.
    Trkov, Andrej
    IAEA, NAPC Nucl Data Sect, Vienna, Austria.
    Wallner, Anton
    Australian Natl Univ, Res Sch Phys & Engn, Canberra, ACT, Australia.
    Wang, Wenming
    China Inst Atom Energy, CNDC, Beijing, Peoples R China.
    Results of a New Evaluation of the Neutron Standards2018In: Reactor Dosimetry: 16th International Symosium / [ed] Sparks, MH DePriest, KR Vehar, DW, ASTM International, 2018, p. 91-104Conference paper (Refereed)
    Abstract [en]

    An international effort has produced evaluations of the neutron data standards. Evaluations were obtained for the cross section standards: the H(n,n), 6Li(n,t), 10B(n,067), loB(vx), natc(n,n,) Au(n,y), 235U(n,f), and 238U(n,f) reactions. Also in the evaluation process, the 238U(n,y) and 239Pu(n,f) nonstandard cross sections were evaluated. Many of these are dosimetry cross sections. Evaluations were also obtained for data that are not traditional standards: Maxwellian spectrum averaged cross section for the Au(n,y) cross section at 30 keV, reference cross sections for prompt y-ray production in fast neutron-induced reactions, reference cross sections for very high-energy fission cross sections, the 252Cf spontaneous fission neutron spectrum and the 235U thermal fission neutron spectrum, and the thermal constants. The data and covariances were obtained directly from this evaluation procedure as is required by the dosimetry community.

  • 163.
    Carlsson, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Development and Characterization of Parallel-Plate Avalanche Counters for Nuclear Physics Experiments2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Parallel-plate avalanche counters, PPACs, are commonly used to detect fission fragments. The PPAC detects them and mark (very accurately) the time of detection. Such measurements can be used to measure the neutron energy (via time-of-flight) to study neutron-induced fission.This project report provides a method that, together with the discussed improvements, allows the fabrication of good quality PPAC detectors. Several PPACs are manufactured and the electrodes are built from 0.9 µm thick mylar foils which are evaporated with a 40-80 nm thin layer of aluminum.The developed PPACs are characterized with well known radioactive Cf and Am sources (the source characterization also found in this report), and compared against each other. Additionally, the PPAC signal amplitude spectrum are found to follow theoretical expectations with regards to angular dependence, gas pressure and an applied electrode voltage.At a specific applied electrode voltage and range of gas pressures (3-9 mbar), the measured time resolutions are 2.24-1.38 ns. A trend is observed for finer time resolutions at higher gas pressures.

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

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

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

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

  • 166. Cazzaniga, C.
    et al.
    Sundén, Erik Andersson
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Croci, G.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Giacomelli, L.
    Gorini, G.
    Griesmayer, E.
    Grosso, G.
    Kaveney, G.
    Nocente, M.
    Cippo, E. Perelli
    Rebai, M.
    Syme, B.
    Tardocchi, M.
    Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 4, p. 043506-Article in journal (Refereed)
    Abstract [en]

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

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

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

  • 168.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Liquid Scintillators Neutron Response Function: A Tutorial2019In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 38, no 3-4, p. 356-375Article in journal (Refereed)
    Abstract [en]

    This tutorial is devoted to the understanding of the different components that are present in the neutron light output pulse height distribution of liquid scintillators in fusion relevant energy ranges. The basic mechanisms for the generation of the scintillation light are briefly discussed. The different elastic collision processed between the incident neutrons and the hydrogen and carbon atoms are described in terms of probability density functions and the overall response function as their convolution. The results from this analytical approach is then compared with those obtained from simplified and full Monte Carlo simulations. Edge effect, finite energy resolution, light output and transport and competing physical processes between neutron and carbon and hydrogen atoms and their impact on the response functions are discussed. Although the analytical treatment here presented allows only for a qualitative comparison with full Monte Carlo simulations it enables an understanding of the main features present in the response function and therefore provides the ground for the interpretation of more complex response functions such those measured in fusion plasmas. Although the main part of this tutorial is focused on the response function to mono-energetic 2.45 MeV neutrons a brief discussion is presented in case of broad neutron energy spectra and how these can be used to infer the underlying properties of fusion plasmas via the application of a forward modelling method.

  • 169.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Boeglin, W.
    Florida Int Univ, Dept Phys, 11200 SW, Miami, FL 33199 USA.
    Keeling, D.
    Culham Sci Ctr, Culham Ctr Fus Energy, United Kingdom Atom Energy Author, Abingdon OX14 3DB, Oxon, England.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Klimek, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Perez, R. , V
    Discrepancy between estimated and measured fusion product rates on MAST using TRANSP/NUBEAM2019In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 59, no 1, article id 016006Article in journal (Refereed)
    Abstract [en]

    Experimental evidence is presented of a discrepancy between the predicted and measured D-D fusion product rates on MAST Both the neutron and proton production rates, measured independently with a neutron camera and charged fusion product detector array, are approximately 40% lower than those predicted by TRANSP/NUBEAM codes. This deficit is scenario independent and cannot be explained by uncertainties in the typical plasma parameters suspected for such discrepancies, such as electron temperature, the plasma effective charge and the injected neutral beam power. Instead, a possible explanation is an overestimate of the neutron emissivity due to the guiding centre approximation used in NUBEAM to model the fast ion orbits.

  • 170.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Marocco, D.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Moro, F.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Esposito, B.
    ENEA, CR Frascati, Via E Fermi 45, I-00044 Rome, Italy..
    Neural network implementation for ITER neutron emissivity profile recognition2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 637-640Article in journal (Refereed)
    Abstract [en]

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

  • 171.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Donato, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Marini-Bettolo, C.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sangaroon, Siriyaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Measurement of the gamma-ray energy resolution function of EJ301 liquid scintillator using a dual channel ADC2014In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 753, p. 34-37Article in journal (Refereed)
    Abstract [en]

    A comparison of three different methods for the energy calibration of liquid scintillators using gamma-ray sources using only a delay unit and a dual channel ADC is presented. Single Compton edge measurements combined with MCNP simulations of the pulse height spectra are compared with the results obtained using Compton coincidence methods. Good agreement between the three methods is found. Measurements from the three different methods are then combined to provide the best estimate of the energy resolution function. The technique here presented could be easily used in laboratory courses as high performing ADCs become more common and affordable. (C) 2014 Elsevier B.V. All rights reserved.

  • 172.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jones, O. M.
    Boeglin, W. U.
    Perez, R. V.
    Darrow, D. S.
    Klimek, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sharapov, S. E.
    Fitzgerald, M.
    McClements, K. G.
    Keeling, D. L.
    Allan, S. Y.
    Michael, C. A.
    Akers, R. J.
    Conway, N. J.
    Scannell, R.
    Turnyanskiy, M.
    Ericsson, G.
    Energetic ion behaviour in MAST2015In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 57, no 1, p. 014006-Article in journal (Refereed)
    Abstract [en]

    Recent studies of fast ion transport resulting from a range of instabilities, including n = 1 internal kink modes (fishbones and long-lived modes), toroidal Alfven eigenmodes and sawteeth have been carried out at MAST. Strong correlations were found between relative changes in magnetic edge coils signals, edge D alpha signal a fast ion D alpha system, a prototype collimated neutron flux monitor and a recently installed prototype charged fusion product detector array, indicating both redistribution and loss of fast ions. Preliminary interpretation of these observations with a suite of stability, modelling and interpretative codes is discussed.

  • 173.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jones, O. M.
    Garzotti, L.
    McClements, K. G.
    Carr, M.
    Henderson, S. S.
    Sharapov, S. E.
    Klimek, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Impurity transport driven by fishbones in MAST2015In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 3, article id 032002Article in journal (Refereed)
    Abstract [en]

    In MAST, bursting toroidal Alfven eigenmodes and fishbones are observed to give rise to an asymmetric perturbation to the soft x-ray (SXR) emission close to the magnetic axis which grows and decays on the time scale of the fishbone evolution. As the fishbone nears its maximum amplitude, the SXR emission starts to increase (decrease) at radial positions smaller (larger) than the radial position of the magnetic axis. This trend in the SXR emission persists for a few milliseconds, until the fishbone starts to decay in amplitude and the slower overall trend of the SXR emission once again becomes dominant. A preliminary analysis suggests that the change in the SXR emission is due to the localized accumulation of high-Z impurities, sustained against parallel transport by the effects of fishbones on the fast ion population.

  • 174.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sangaroon, Siriyaporn
    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.
    Donato, Mattia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Marini Bettolo, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ronchi, Emanuele
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ström, Petter
    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.
    Wodniak, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Turnyanskiy, Mikhail
    Akers, Rob
    Cullen, Andy
    Fitzgerald, Ian
    McArdle, Graham
    Pacoto, Chris
    Thomas-Davies, Nigel
    The 2.5 MeV neutron flux monitor for MAST2014In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 753, p. 72-83Article in journal (Refereed)
  • 175.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sangaroon, Siriyaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Turnyanskiy, M.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Wodniak, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Akers, R. J.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Observation of fast ion behaviour with a neutron emission profile monitor in MAST2012In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 52, no 9, p. 094015-Article in journal (Refereed)
    Abstract [en]

    Preliminary measurements of neutron emissivity at the Mega Amp Spherical Tokamak (MAST) along collimated lines-of-sight showa clear correlation between the neutron emissivity temporal and spatial evolution and the evolution of different MHD instabilities. In particular, the variations in neutron emissivity during sawtooth oscillations are compared with changes in the classical fast ion slowing-down time, while fast ion losses are observed in bursts during fishbones or as a continuous process during long-lived modes.

  • 176.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sperduti, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Study of the effect of sawteeth on fast ions and neutron emission in MAST using a neutron camera2018In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 60, no 5, article id 055008Article in journal (Refereed)
    Abstract [en]

    The effect of the sawtooth instability on the confinement of fast ions on MAST, and the impact it has on the neutron emission, has been studied in detail using the TRANSP/NUBEAM codes coupled to a full orbit following code. The sawtooth models in TRANSP/NUBEAM indicate that, on MAST, passing and trapped fast ions are redistributed in approximately equal number and on a level that is consistent with the observations. It has not been possible to discriminate between the different sawtooth models since their predictions are all compatible with the neutron camera observations. Full orbit calculations of the fast ion motion have been used to estimate the characteristic time scales and energy thresholds that according to theoretical predictions govern the fast ions redistribution: no energy threshold for the redistribution for either passing and trapped fast ions was found. The characteristic times have, however, frequencies that are comparable with the frequencies of a m = 1, n = 1 perturbation and its harmonics with toroidal mode numbers n = 2, ..., 4, suggesting that on spherical tokamaks, in addition to the classical sawtooth-induced transport mechanisms of fast ions by attachment to the evolving perturbation and the associated E x B drift, a resonance mechanism between the m = 1 perturbation and the fast ions orbits might be at play.

  • 177.
    Cecconello, Marco
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EURATOM VR Assoc, Uppsala, Sweden.
    Sperduti, Andrea
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EURATOM VR Assoc, Uppsala, Sweden.
    Fitzgerald, I.
    Culham Sci Ctr, EURATOM CCFE Fus Assoc, Abingdon, Oxon, England.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EURATOM VR Assoc, Uppsala, Sweden.
    Holm, Stefan Jarl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EURATOM VR Assoc, Uppsala, Sweden.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EURATOM VR Assoc, Uppsala, Sweden.
    The neutron camera upgrade for MAST Upgrade2018In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 89, no 10, article id 10I110Article in journal (Refereed)
    Abstract [en]

    The Neutron Camera Upgrade (NCU) is a neutron flux monitor consisting of six lines of sight (LoSs) under installation on Mega Ampere Spherical Tokamak (MAST) Upgrade. The NCU is expected to contribute to the study of the confinement of fast ions and on the efficiency of non-inductive current drive in the presence of on-axis and off-axis neutral beam injection by measuring the neutron emissivity profile along the equatorial plane. This paper discusses the NCU main design criteria, the engineering and interfacing issues, and the solutions adopted. In addition, the results from the characterization and performance studies of the neutron detectors using standard gamma-rays sources and a Cf-252 source are discussed. The proposed design has a time resolution of 1 ms with a statistical uncertainty of less than 10% for all MAST Upgrade scenarios with a spatial resolution of 10 cm: higher spatial resolution is possible by moving the LoSs in-between plasma discharges. The energy resolution of the neutron detector is better than 10% for a light output of 0.8 MeVee, and the measured pulse shape discrimination is satisfactory.

  • 178.
    Chahoud, George
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Vestin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Virtuell presentation elmatning2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Forsmarks Kraftgrupp has previously used photographical presentations of parts of

    their site and wanted to proceed with an interactive presentation containing

    panoramic images linked with information of the objects represented in the images.

    The goal of this project was to create a virtual presentation of selected parts of the D

    sub as well as investigate what was needed in terms of resources if the sub in its

    whole was to be documented. Instructions on how to use and update the

    presentation were also to be made.

    This degree project was closely linked to the degree project “Sfärisk fotografering till

    virtuella presentationer” conducted by Björn Bartholdsson and Erik Hultgren. All

    photos and panoramas used in this project were taken and edited as a part of their

    project.

    This project resulted in:

    •A presentation made in Easypano Tourweaver containing spherical and cylindrical

    panoramas stitched in Panoweaver.

    •Instructions for the use of Easypanos products.

    •A estimate of the time demanded for a complete presentation of the D sub.

  • 179.
    Chapman, I. T.
    et al.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Adamek, J.
    AS CR, Inst Plasma Phys, Vvi, Prague, Czech Republic..
    Akers, R. J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Allan, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Appel, L.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Asunta, O.
    Aalto Univ, TEKES, Espoo, Finland..
    Barnes, M.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Ben Ayed, N.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Bigelow, T.
    Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA..
    Boeglin, W.
    Florida Int Univ, Dept Phys, Miami, FL 33199 USA..
    Bradley, J.
    Univ Liverpool, Dept Elect Engn & Elect, Liverpool L69 3BX, Merseyside, England..
    Bruenner, J.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Cahyna, P.
    AS CR, Inst Plasma Phys, Vvi, Prague, Czech Republic..
    Carr, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Caughman, J.
    Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA..
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Challis, C.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Chapman, S.
    Univ Warwick, Dept Phys, Ctr Fus Space & Astrophys, Coventry CV4 7AL, W Midlands, England..
    Chorley, J.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Colyer, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Conway, N.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Cooper, W. A.
    Ecole Polytech Fed Lausanne, CRPP, CH-1015 Lausanne, Switzerland..
    Cox, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Crocker, N.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Crowley, B.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Cunningham, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Danilov, A.
    Inst Nucl Fus, Kurchatov Inst, Russian Res Ctr, Moscow, Russia..
    Darrow, D.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Dendy, R.
    Univ Warwick, Dept Phys, Ctr Fus Space & Astrophys, Coventry CV4 7AL, W Midlands, England..
    Diallo, A.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Dickinson, D.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Diem, S.
    Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA..
    Dorland, W.
    Univ Maryland, College Pk, MD 20742 USA..
    Dudson, B.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Dunai, D.
    KFKI RMKI, H-1525 Budapest, Hungary..
    Easy, L.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Elmore, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Field, A.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Fishpool, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Fox, M.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Fredrickson, E.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Freethy, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Garzotti, L.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Ghim, Y. C.
    Natl Fus Res Inst, Daejeon 169148, South Korea..
    Gibson, K.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Graves, J.
    Ecole Polytech Fed Lausanne, CRPP, CH-1015 Lausanne, Switzerland..
    Gurl, C.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Guttenfelder, W.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Ham, C.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Harrison, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Harting, D.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Havlickova, E.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Hawke, J.
    Dutch Inst Fundamental Energy Res, NL-3430 BE Nieuwegein, Netherlands..
    Hawkes, N.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Hender, T.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Henderson, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England.;Univ Strathclyde, Dept Phys SUPA, Glasgow G4 ONG, Lanark, Scotland..
    Highcock, E.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Hillesheim, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Hnat, B.
    Univ Warwick, Dept Phys, Ctr Fus Space & Astrophys, Coventry CV4 7AL, W Midlands, England..
    Holgate, J.
    Univ Cambridge, Cavendish Lab, Dept Phys, Cambridge CB3 0HE, England..
    Horacek, J.
    AS CR, Inst Plasma Phys, Vvi, Prague, Czech Republic..
    Howard, J.
    Australian Natl Univ, Plasma Res Lab, Canberra, ACT 0200, Australia..
    Huang, B.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Imada, K.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Jones, O.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Kaye, S.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Keeling, D.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Kirk, A.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Klimek, Iwona
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kocan, M.
    ITER Org, CS 90046, F-13067 St Paul Les Durance, France..
    Leggate, H.
    Dublin City Univ, Dublin 9, Ireland..
    Lilley, M.
    Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2AZ, England..
    Lipschultz, B.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Lisgo, S.
    ITER Org, CS 90046, F-13067 St Paul Les Durance, France..
    Liu, Y. Q.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Lloyd, B.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Lomanowski, B.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Lupelli, I.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Maddison, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Mailloux, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Martin, R.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    McArdle, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    McClements, K.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    McMillan, B.
    Univ Warwick, Dept Phys, Ctr Fus Space & Astrophys, Coventry CV4 7AL, W Midlands, England..
    Meakins, A.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Meyer, H.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Michael, C.
    Australian Natl Univ, Plasma Res Lab, Canberra, ACT 0200, Australia..
    Militello, F.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Milnes, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Morris, A. W.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Motojima, G.
    NIFS, Toki, Gifu, Japan..
    Muir, D.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Nardon, E.
    CEN Cadarache, F-13108 St Paul Les Durance, France..
    Naulin, V.
    Risoe, Natl Lab Sustainable Energy, Roskilde, Denmark..
    Naylor, G.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Nielsen, A.
    Risoe, Natl Lab Sustainable Energy, Roskilde, Denmark..
    O'Brien, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    O'Gorman, T.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Ono, Y.
    Univ Tokyo, Kashiwa, Chiba 2778561, Japan..
    Oliver, H.
    Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England..
    Pamela, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Pangione, L.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Parra, F.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Patel, A.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Peebles, W.
    Univ Calif Los Angeles, Los Angeles, CA 90095 USA..
    Peng, M.
    Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA..
    Perez, R.
    Florida Int Univ, Dept Phys, Miami, FL 33199 USA..
    Pinches, S.
    ITER Org, CS 90046, F-13067 St Paul Les Durance, France..
    Piron, L.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Podesta, M.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Price, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Reinke, M.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Ren, Y.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Roach, C.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Robinson, J.
    Univ Warwick, Dept Phys, Ctr Fus Space & Astrophys, Coventry CV4 7AL, W Midlands, England..
    Romanelli, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Rozhansky, V.
    St Petersburg State Polytech Univ, Dept Plasma Phys, St Petersburg, Russia..
    Saarelma, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Sangaroon, Siriyaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Saveliev, A.
    Ioffe Inst, St Petersburg 194021, Russia..
    Scannell, R.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Schekochihin, A.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Sharapov, S.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Sharples, R.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Shevchenko, V.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Silburn, S.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Simpson, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Storrs, J.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Takase, Y.
    Univ Tokyo, Kashiwa, Chiba 2778561, Japan..
    Tanabe, H.
    Univ Tokyo, Kashiwa, Chiba 2778561, Japan..
    Tanaka, H.
    Kyoto Univ, Grad Sch Energy Sci, Kyoto 6068502, Japan..
    Taylor, D.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Taylor, G.
    Princeton Plasma Phys Lab, Princeton, NJ 08543 USA..
    Thomas, D.
    Univ Durham, Dept Phys, Durham DH1 3LE, England..
    Thomas-Davies, N.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Thornton, A.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Turnyanskiy, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Valovic, M.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England..
    Vann, R.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Walkden, N.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Wilson, H.
    Univ York, Dept Phys, York Plasma Inst, York YO10 5DD, N Yorkshire, England..
    Wyk, L. V.
    Univ Oxford, Rudolf Peierls Ctr Theoret Phys, Oxford, England..
    Yamada, T.
    Univ Tokyo, Kashiwa, Chiba 2778561, Japan..
    Zoletnik, S.
    KFKI RMKI, H-1525 Budapest, Hungary..
    Overview of MAST results2015In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 55, no 10, article id 104008Article in journal (Refereed)
    Abstract [en]

    The Mega Ampere Spherical Tokamak (MAST) programme is strongly focused on addressing key physics issues in preparation for operation of ITER as well as providing solutions for DEMO design choices. In this regard, MAST has provided key results in understanding and optimizing H-mode confinement, operating with smaller edge localized modes (ELMs), predicting and handling plasma exhaust and tailoring auxiliary current drive. In all cases, the high-resolution diagnostic capability on MAST is complemented by sophisticated numerical modelling to facilitate a deeper understanding. Mitigation of ELMs with resonant magnetic perturbations (RMPs) with toroidal mode number n(RMP) = 2, 3, 4, 6 has been demonstrated: at high and low collisionality; for the first ELM following the transition to high confinement operation; during the current ramp-up; and with rotating n(RMP) = 3 RMPs. n(RMP) = 4, 6 fields cause less rotation braking whilst the power to access H-mode is less with n(RMP) = 4 than n(RMP) = 3, 6. Refuelling with gas or pellets gives plasmas with mitigated ELMs and reduced peak heat flux at the same time as achieving good confinement. A synergy exists between pellet fuelling and RMPs, since mitigated ELMs remove fewer particles. Inter-ELM instabilities observed with Doppler backscattering are consistent with gyrokinetic simulations of micro-tearing modes in the pedestal. Meanwhile, ELM precursors have been strikingly observed with beam emission spectroscopy (BES) measurements. A scan in beta at the L-H transition shows that pedestal height scales strongly with core pressure. Gyro-Bohm normalized turbulent ion heat flux (as estimated from the BES data) is observed to decrease with increasing tilt of the turbulent eddies. Fast ion redistribution by energetic particle modes depends on density, and access to a quiescent domain with 'classical' fast ion transport is found above a critical density. Highly efficient electron Bernstein wave current drive (1 A W-1) has been achieved in solenoid-free start-up. A new proton detector has characterized escaping fusion products. Langmuir probes and a high-speed camera suggest filaments play a role in particle transport in the private flux region whilst coherence imaging has measured scrape-off layer (SOL) flows. BOUT++ simulations show that fluxes due to filaments are strongly dependent on resistivity and magnetic geometry of the SOL, with higher radial fluxes at higher resistivity. Finally, MAST Upgrade is due to begin operation in 2016 to support ITER preparation and importantly to operate with a Super-X divertor to test extended leg concepts for particle and power exhaust.

  • 180.
    Charnay, Vincent
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ion-induced electron emission in backscattering and transmission geometry2019Independent thesis Basic level (degree of Bachelor), 10 HE creditsStudent thesis
    Abstract [en]

    Medium energy ion scattering (MEIS) is an experimental technique for the high-resolution depth profiling of thin films. This project aims to perform an analysis of ion-inducted electron emission in backscattering and transmission geometry. Electron emitted via the impact of medium-energy ions can be detected with a time-of-flight approach. By analyzing their time-offlight on the spectrum, electrons energies and their origins can be determined.

  • 181.
    Chen, James
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    In-situ study of the chemical composition ofphotochromic Yttrium Oxy-Hydrides thin films2019Student paper other, 10 HE creditsStudent thesis
  • 182.
    Chulapakorn, Thawatchart
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Luminescence of Silicon Nanoparticles Synthesized by Ion Implantation2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Silicon nanoparticles (SiNPs) have been shown to display luminescence in the visible range with a peak wavelength depending on the nanoparticle size. This finding is of potential interest for integration of optoelectronic devices in semiconductor technology. In this thesis, silicon nanoparticles are formed in thermally grown SiO2 films by implantation of Si-ions. Implantation parameters such as energy, fluence, and target temperature, as well as post-implantation annealing (PIA) conditions are studied in order to optimize the luminescence properties of the nanoparticles. Ion energies between 15 and 70 keV, fluences up to 1017 atoms/cm2, and target temperatures ranging from room temperature to 600 ºC are employed. The PIA process is carried out at temperatures between 1000 and 1200 °C in ambient nitrogen, or argon gas. In addition, dangling bonds, which reduce the total luminescence of SiNPs, are passivated, using forming gas annealing (FGA). Quantification of hydrogen content induced by FGA process is performed by ion beam analysis (IBA) techniques. Furthermore, irradiations with swift heavy ions (SHIs) with several tens of MeV kinetic energy are performed as a possible way to further reduce the defect density. In particular, the relation between electronic and nuclear stopping for the defect production and annealing is investigated. The composition and physical structure of the samples are studied via IBA techniques, transmission electron microscopy (TEM), and grazing incidence X-ray diffraction (GIXRD). Based on the results from IBA, the implantation profiles are reconstructed. The physical structures of SiNPs revealed by TEM and GIXRD, furthermore, show that the high fluence implantation with an adequate PIA condition leads to the formation of crystalline SiNPs with a mean size of about 6 nm. The optical properties of SiNPs are characterized by photoluminescence (PL) techniques. After the implantation, only defect PL is present, but it is found that intense SiNP PL can be achieved for samples implanted with 15 atomic% excess peak concentration of Si in SiO2 and PIA at 1100 °C in argon gas for 90 minutes. Finally, an alternative way for fabricating SiNPs in SiO2 is tested, using oxygen implantation into a Si wafer. Although the PL from this experiment is less intense than the PL of SiNPs fabricated by the Si-implanted SiO2 route, the results are technologically interesting due to the convenience of the process.

  • 183.
    Chulapakorn, Thawatchart
    et al.
    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.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Impact of H-Uptake from Forming Gas Annealing and Ion Implantation on the Photoluminescence of Si Nanoparticles2018In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 215, no 3, article id 1700444Article in journal (Refereed)
    Abstract [en]

    Silicon nanoparticles (SiNPs) are formed by implanting 70keV Si+ into a SiO2-film and subsequent thermal annealing. SiNP samples are further annealed in forming gas. Another group of samples containing SiNP is implanted by 7.5keV H+ and subsequently annealed in N-2-atmosphere at 450 degrees C to reduce implantation damage. Nuclear reaction analysis (NRA) is employed to establish depth profiles of the H-concentration. Enhanced hydrogen concentrations are found close to the SiO2 surface, with particularly high concentrations for the as-implanted SiO2. However, no detectable uptake of hydrogen is observed by NRA for samples treated by forming gas annealing (FGA). H-concentrations detected after H-implantation follow calculated implantation profiles. Photoluminescence (PL) spectroscopy is performed at room temperature to observe the SiNP PL. Whereas FGA is found to increase PL under certain conditions, i.e., annealing at high temperatures, increasing implantation fluence of H reduces the SiNP PL. Hydrogen implantation also introduces additional defect PL. After low-temperature annealing, the SiNP PL is found to improve, but the process is not found equivalently efficient as conventional FGA.

  • 184.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Moro, Marcos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Hallén, Anders
    Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Luminescence of Silicon Nanoparticles from Oxygen Implanted Silicon2018In: Materials Science in Semiconductor Processing, ISSN 1369-8001, E-ISSN 1873-4081, Vol. 86, p. 18-22Article in journal (Refereed)
    Abstract [en]

    Oxygen with a kinetic energy of 20 keV is implanted in a silicon wafer (100) at different fluences, followed by post-implantation thermal annealing (PIA) performed at temperatures ranging from 1000 to 1200 degrees C, in order to form luminescent silicon nanoparticles (SiNPs) and also to reduce the damage induced by the implantation. As a result of this procedure, a surface SiOx layer (with 0 < x < 2) with embedded crystalline Si nanoparticles has been created. The samples yield similar luminescence in terms of peak wavelength, lifetime, and absorption as recorded from SiNPs obtained by the more conventional method of implanting silicon into silicon dioxide. The oxygen implantation profile is characterized by elastic recoil detection (ERD) technique to obtain the excess concentration of Si in a presumed SiO2 environment. The physical structure of the implanted Si wafer is examined by grazing incidence X-ray diffraction (GIXRD). Photoluminescence (PL) techniques, including PL spectroscopy, time-resolved PL (TRPL), and photoluminescence excitation (PLE) spectroscopy are carried out in order to identify the PL origin. The results show that luminescent SiNPs are formed in a Si sample implanted by oxygen with a fluence of 2 x 10(17) atoms cm(-2) and PIA at 1000 degrees C. These SiNPs have a broad size range of 6-24 nm, as evaluated from the GIXRD result. Samples implanted at a lower fluence and/or annealed at higher temperature show only weak defect-related PL. With further optimization of the SiNP luminescence, the method may offer a simple route for integration of luminescent Si in mainstream semiconductor fabrication.

  • 185.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Influence of Swift Heavy Ion Irradiation on the Photoluminescence of Si-nanoparticles and Defects in SiO22017In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 28, no 37, article id 375603Article in journal (Refereed)
    Abstract [en]

    The influence of swift heavy ion (SHI) irradiation on the photoluminescence (PL) of silicon nanoparticles (SiNPs) and defects in SiO2-film is investigated. SiNPs were formed by implantation of 70 keV Si+ and subsequent thermal annealing to produce optically active SiNPs and to remove implantation-induced defects. Seven different ion species with energy between 3-36 MeV and fluence from 10(11)-10(14) cm(-2) were employed for irradiation of the implanted samples prior to the thermal annealing. Induced changes in defect and SiNP PL were characterized and correlated with the specific energy loss of the employed SHIs. We find that SHI irradiation, performed before the thermal annealing process, affects both defect and SiNP PL. The change of defect and SiNP PL due to SHI irradiation is found to show a threshold-like behaviour with respect to the electronic stopping power, where a decrease in defect PL and an anticorrelated increase in SiNP PL after the subsequent thermal annealing are observed for electronic stopping exceeding 3-5 keV nm(-1). PL intensities are also compared as a function of total energy deposition and nuclear energy loss. The observed effects can be explained by ion track formation as well as a different type of annealing mechanisms active for SHI irradiation compared to the thermal annealing.

  • 186.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    MeV Ion Irradiation Effects on the Luminescence Properties of Si-implanted SiO2-thin Films2016In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 13, no 10-12, p. 921-926Article in journal (Refereed)
    Abstract [en]

    The effects of MeV heavy ion irradiation at varying fluence and flux on excess Si, introduced in SiO2 by keV ion implantation, are investigated by photoluminescence (PL). From the PL peak wavelength (lambda) and decay lifetime (t), two PL sources are distinguished: i) quasi-direct recombination of excitons of Si-nanoparticles (SiNPs), appearing after thermal annealing (lambda > 720 nm, tau similar to mu s), and ii) fast-decay PL, possibly due to oxide-related defects (lambda similar to 575-690 nm, tau similar to ns). The fast-decay PL (ii) observed before and after ion irradiation is induced by ion implantation. It is found that this fast-decay luminescence decreases for higher irradiation fluence of MeV heavy ions. After thermal annealing (forming SiNPs), the SiNP PL is reduced for samples irradiated by MeV heavy ions but found to stabilize at higher level for higher irradiation flux; the (ii) band vanishes as a result of annealing. The results are discussed in terms of the influence of electronic and nuclear stopping powers.

  • 187.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Wolff, Max
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Si-nanoparticle Synthesis Using Ion Implantation and MeV Ion Irradiation2015In: Physica Status Solidi C: Current Topics In Solid State Physics, Vol 12, No 12 / [ed] Mascher, P; Moreels, I; Climente, JI; Andre, P; Reece, P; Ribierre, JC; Pereira, L; Philippe, L; Pellicer, E, 2015, no 12, p. 1301-1305Conference paper (Refereed)
    Abstract [en]

    A dielectric matrix with embedded Si-nanoparticles may show strong luminescence depending on nanoparticles size, surface properties, Si-excess concentration and matrix type. Ion implantation of Si ions with energies of a few tens to hundreds of keV in a SiO2 matrix followed by thermal annealing was identified as a powerful method to form such nanoparticles. The aim of the present work is to optimize the synthesis of Si-nanoparticles produced by ion implantation in SiO2 by employing MeV ion irradiation as an additional annealing process. The luminescence properties are measured by spectrally resolved photoluminescence including PL lifetime measurement, while X-ray reflectometry, atomic force microscopy and ion beam analysis are used to characterize the nanoparticle formation process. The results show that the samples implanted at 20%-Si excess atomic concentration display the highest luminescence and that irradiation of 36 MeV 127I ions affects the luminosity in terms of wavelength and intensity. It is also demonstrated that the nanoparticle luminescence lifetime decreases as a function of irradiation fluence.

  • 188.
    Chulapakorn, Thawatchart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sychugov, Ilya
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Suvanam, Sethu Saveda
    Royal Institute of Technology (KTH), School of Information and Communication Technology, PO Box Electrum 229, SE-16440 Kista, Sweden.
    Xie, Ling
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Ottosson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    LEIFER, KLAUS
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Linnros, Jan
    Royal Institute of Technology (KTH), Department of Materials and Nano Physics, SE-164 40 Kista, Sweden.
    Hallén, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Royal Institute of Technology, School of Information & Communication Technology, SE-16440 Kista, Sweden.
    Ion Beam Synthesis of Luminescent Silicon NanoparticlesManuscript (preprint) (Other academic)
  • 189.
    Clack, Christopher T. M.
    et al.
    NOAA, Earth Syst Res Lab, Boulder, CO 80305 USA.;Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80305 USA.;Vibrant Clean Energy LLC, Erie, CO 80516 USA..
    Qvist, Staffan A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Apt, Jay
    Carnegie Mellon Univ, Dept Engn & Publ Policy, Pittsburgh, PA 15213 USA.;Carnegie Mellon Univ, Tepper Sch Business, Pittsburgh, PA 15213 USA..
    Bazilian, Morgan
    Columbia Univ, Ctr Global Energy Policy, New York, NY 10027 USA..
    Brandt, Adam R.
    Stanford Univ, Dept Energy Resources Engn, Stanford, CA 94305 USA..
    Caldeira, Ken
    Carnegie Inst Sci, Dept Global Ecol, Stanford, CA 94305 USA..
    Davis, Steven J.
    Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA..
    Diakov, Victor
    Omni Optimum, Evergreen, CO 80437 USA..
    Handschy, Mark A.
    Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80305 USA.;Enduring Energy LLC, Boulder, CO 80303 USA..
    Hines, Paul D. H.
    Univ Vermont, Elect Engn & Complex Syst Ctr, Burlington, VT 05405 USA..
    Jaramillo, Paulina
    Carnegie Mellon Univ, Dept Engn & Publ Policy, Pittsburgh, PA 15213 USA..
    Kammen, Daniel M.
    Univ Calif Berkeley, Energy & Resources Grp, Berkeley, CA 94720 USA.;Univ Calif Berkeley, Goldman Sch Publ Policy, Berkeley, CA 94720 USA.;Univ Calif Berkeley, Renewable & Appropriate Energy Lab, Berkeley, CA 94720 USA..
    Long, Jane C. S.
    Lawrence Livermore Natl Lab, Livermore, CA 94550 USA..
    Morgan, M. Granger
    Carnegie Mellon Univ, Dept Engn & Publ Policy, Pittsburgh, PA 15213 USA..
    Reed, Adam
    Univ Colorado, Renewable & Sustainable Energy Inst, Boulder, CO 80305 USA..
    Sivaram, Varun
    Council Foreign Relat, New York, NY 10065 USA..
    Sweeney, James
    Stanford Univ, Precourt Energy Efficiency Ctr, Stanford, CA 94305 USA.;Stanford Univ, Management Sci & Engn Dept, Huang Engn Ctr, Stanford, CA 94305 USA..
    Tynan, George R.
    Univ Calif San Diego, Dept Mech & Aerosp Engn, Jacobs Sch Engn, La Jolla, CA 92093 USA..
    Victor, David G.
    Univ Calif San Diego, Sch Global Policy & Strategy, La Jolla, CA 92093 USA.;Brookings Inst, Washington, DC 20036 USA..
    Weyant, John P.
    Stanford Univ, Precourt Energy Efficiency Ctr, Stanford, CA 94305 USA.;Stanford Univ, Management Sci & Engn Dept, Huang Engn Ctr, Stanford, CA 94305 USA..
    Whitacre, Jay F.
    Carnegie Mellon Univ, Dept Engn & Publ Policy, Pittsburgh, PA 15213 USA..
    Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar2017In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 114, no 26, p. 6722-6727Article in journal (Refereed)
    Abstract [en]

    A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49): 15060-15065] argue that it is feasible to provide "low-cost solutions to the grid reliability problem with 100% penetration of WWS [wind, water and solar power] across all energy sectors in the continental United States between 2050 and 2055", with only electricity and hydrogen as energy carriers. In this paper, we evaluate that study and find significant shortcomings in the analysis. In particular, we point out that this work used invalid modeling tools, contained modeling errors, and made implausible and inadequately supported assumptions. Policy makers should treat with caution any visions of a rapid, reliable, and low-cost transition to entire energy systems that relies almost exclusively on wind, solar, and hydroelectric power.

  • 190. Coelho, R.
    et al.
    Akaslompolo, S.
    Dinklage, A.
    Kus, A.
    Reimer, R.
    Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Blanco, E.
    Conway, G.
    Hacquin, S.
    Heuraux, S.
    Lechte, C.
    Da Silva, F.
    Sirinelli, A.
    Synthetic Diagnostics In The European Union Integrated Tokamak Modelling Simulation Platform2013In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 63, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    The European Union Integrated Tokamak Modelling Task Force (ITM-TF) has developed a standardized platform and an integrated modeling suite of codes for the simulation and prediction of a complete plasma discharge in any tokamak. The framework developed by ITM-TF allows for the development of sophisticated integrated simulations (workflows) for physics application, e.g., free-boundary equilibrium with feedback control, magnetohydrodynamic stability analysis, core/edge plasma transport, and heating and current drive. A significant effort is also under way to integrate synthetic diagnostic modules in the ITM-TF environment, namely, focusing on three-dimensional reflectometry, motional Stark effect, and neutron and neutral particle analyzer diagnostics. This paper gives an overview of the conceptual design of ITM-TF and preliminary results of the aforementioned synthetic diagnostic modules.

  • 191. Collaboration, The n_TOF
    et al.
    Gunsing, F.
    Aberle, O.
    Andrzejewski, J.
    Audouin, L.
    Bécares, V.
    Bacak, M.
    Balibrea-Correa, J.
    Barbagallo, M.
    Barros, S.
    Bečvář, F.
    Beinrucker, C.
    Belloni, F.
    Berthoumieux, E.
    Billowes, J.
    Bosnar, D.
    Brugger, M.
    Caamaño, M.
    Calviño, F.
    Calviani, M.
    Cano-Ott, D.
    Cardella, R.
    Casanovas, A.
    Castelluccio, D. M.
    Cerutti, F.
    Chen, Y. H.
    Chiaveri, E.
    Colonna, N.
    Cortés-Giraldo, M. A.
    Cortés, G.
    Cosentino, L.
    Damone, L. A.
    Deo, K.
    Diakaki, M.
    Domingo-Pardo, C.
    Dressler, R.
    Dupont, E.
    Durán, I.
    Fernández-Domínguez, B.
    Ferrari, A.
    Ferreira, P.
    Finocchiaro, P.
    Frost, R. J. W.
    Furman, V.
    Ganesan, S.
    García, A. R.
    Gawlik, A.
    Gheorghe, I.
    Glodariu, T.
    Gonçalves, I. F.
    González, E.
    Goverdovski, A.
    Griesmayer, E.
    Guerrero, C.
    Göbel, K.
    Harada, H.
    Heftrich, T.
    Heinitz, S.
    Hernández-Prieto, A.
    Heyse, J.
    Jenkins, D. G.
    Jericha, E.
    KÀppeler, F.
    Kadi, Y.
    Katabuchi, T.
    Kavrigin, P.
    Ketlerov, V.
    Khryachkov, V.
    Kimura, A.
    Kivel, N.
    Kokkoris, M.
    Krtička, M.
    Leal-Cidoncha, E.
    Lederer, C.
    Leeb, H.
    Lerendegui, J.
    Licata, M.
    Lo Meo, S.
    Lonsdale, S. J.
    Losito, R.
    Macina, D.
    Marganiec, J.
    Martínez, T.
    Masi, A.
    Massimi, C.
    Mastinu, P.
    Mastromarco, M.
    Matteucci, F.
    Maugeri, E. A.
    Mazzone, A.
    Mendoza, E.
    Mengoni, A.
    Milazzo, P. M.
    Mingrone, F.
    Mirea, M.
    Montesano, S.
    Musumarra, A.
    Nolte, R.
    Oprea, A.
    Palomo-Pinto, F. R.
    Paradela, C.
    Patronis, N.
    Pavlik, A.
    Perkowski, J.
    Porras, I.
    Praena, J.
    Quesada, J. M.
    Rajeev, K.
    Rauscher, T.
    Reifarth, R.
    Riego-Perez, A.
    Robles, M.
    Rout, P.
    Radeck, D.
    Rubbia, C.
    Ryan, J. A.
    Sabaté-Gilarte, M.
    Saxena, A.
    Schillebeeckx, P.
    Schmidt, S.
    Schumann, D.
    Sedyshev, P.
    Smith, A. G.
    Stamatopoulos, A.
    Suryanarayana, S. V.
    Tagliente, G.
    Tain, J. L.
    Tarifeño-Saldivia, A.
    Tarrio, D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Tassan-Got, L.
    Tsinganis, A.
    Valenta, S.
    Vannini, G.
    Variale, V.
    Vaz, P.
    Ventura, A.
    Vlachoudis, V.
    Vlastou, R.
    Wallner, A.
    Warren, S.
    Weigand, M.
    Weiss, C.
    Wolf, C.
    Woods, P. J.
    Wright, T.
    Åœugec, P.
    Nuclear data activities at the n_TOF facility at CERN2016In: Eur. Phys. J. Plus, Vol. 131, no 10Article in journal (Refereed)
  • 192.
    Constanda, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Control Rod Effect at Partial SCRAM: Upgrade of Plant Model for Forsmark 2 in BISON After Power Uprate2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study aims to improve the modeling of partial SCRAM in the BISON plant model for the Forsmark 2 nuclear reactor after power uprate. Validation of the BISON model against tests performed from March to May in 2013 have shown that this is one of the areas in which there is room for improvement. After partial SCRAM is performed, the model underestimates the reactor power, recirculation flow and steam flow when compared to the measurement data.

    In BISON the partial SCRAM is modeled using a relative control rod effect vector (ASC vector). The aim is to replace the old values in this vector to improve the model. The new model was shown to give an improved result for the reactor power, recirculation flow and steam flow. The study gives recommendations on how to apply the new model and what values of the relative control rod effect vector that can be used in the future.

  • 193.
    Cruz, N.
    et al.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Pereira, R. C.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Santos, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Fernandes, A.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Sousa, J.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Marocco, D.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Riva, M.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Centioli, C.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Correia, C. M. B.
    Univ Coimbra, Dept Fis, LIBPhys UC, P-3004516 Coimbra, Portugal..
    Goncalves, B.
    Univ Lisbon, Inst Super Tecn, Inst Plasmas & Fusao Nucl, P-1049001 Lisbon, Portugal..
    Esposito, B.
    ENEA, CR Frascati, Dipartimento FSN, Via E Fermi,45 Frascati, I-00044 Rome, Italy..
    Real-time software tools for the performance analysis of the ITER Radial Neutron Camera2017In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1001-1005Article in journal (Refereed)
    Abstract [en]

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

  • 194.
    Cufar, Aljaz
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Batistoni, Paola
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Ghani, Zamir
    Culham Ctr Fus Energy, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Milocco, Alberto
    Culham Ctr Fus Energy, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Packer, Lee
    Culham Ctr Fus Energy, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Pillon, Mario
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Popovichev, Sergey
    Culham Ctr Fus Energy, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.;EUROfus Consortium, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England..
    Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator2017In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 847, p. 199-204Article in journal (Refereed)
    Abstract [en]

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  • 195.
    Cufar, Aljaz
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Batistoni, Paola
    ENEA, Dept Fus & Nucl Safety Technol, I-00044 Rome, Italy.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ghani, Zamir
    CCFE UKAEA, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Popovichev, Sergey
    CCFE UKAEA, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.
    Syme, Brian
    CCFE UKAEA, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England.
    Stancar, Ziga
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia.
    Calculations to Support In Situ Neutron Yield Calibrations at the Joint European Torus2018In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 74, no 4, p. 370-386Article in journal (Refereed)
    Abstract [en]

    The fusion power output of fusion plasmas is measured using the neutron yield detectors due to its linear relation to the fusion yield. Absolutely calibrated neutron yield detectors are thus a crucial part of the plasma diagnostics system and the absolute accuracy of their calibration must be ensured. The transition of the Joint European Torus's (JET's) first wall material from carbon (C) wall to ITER-like (Be/W/C) first wall was a significant change in the structure of the machine and recalibration of the main neutron yield detectors was needed to maintain the required measurement uncertainty of less than +/- 10%. The neutron yield detectors were thus recalibrated through two in situ calibrations to deuterium-deuterium neutrons in 2013 and deuterium-tritium neutrons in 2017 using 252Cf spontaneous fission source and a compact neutron generator, respectively. We describe the extensive neutronics calculations performed in support of these latest calibration experiments. These analyses were performed using Monte Carlo simulations to better understand the calibration procedure, optimize the experiments, ensure personnel safety, and quantify the effects of the uncharacteristic circumstances during calibration experiments. This paper focuses on assessments of the effects of the uncharacteristic circumstances, e. g., the presence of the remote handling system in the machine due to its use in neutron source delivery, difference in the neutron emission spectrum, and differences in the neutron source shape. Lessons learned, findings, and relevance for calibrations of future large tokamaks are discussed.

  • 196.
    Cufar, Aljaz
    et al.
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Lengar, Igor
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Kodeli, Ivan
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Milocco, Alberto
    Culham Sci Ctr, Culham Ctr Fus Energy, Abingdon OX14 3DB, Oxon, England..
    Sauvan, Patrick
    UNED, ETS Ingn Ind, Dept Ingn Energet, C Juan del Rosal 12, Madrid 28040, Spain..
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Snoj, Luka
    Jozef Stefan Inst, Reactor Phys Dept, Jamova Cesta 39, SI-1000 Ljubljana, Slovenia..
    Comparison of DT neutron production codes MCUNED, ENEA-JSI source subroutine and DDT2016In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 109, p. 164-168Article in journal (Refereed)
    Abstract [en]

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

  • 197.
    Dalbauer, V
    et al.
    TU Wien, Christian Doppler Lab Applicat Oriented Coating D, Inst Mat Sci & Technol, Vienna, Austria.
    Ramm, J.
    Oerlikon Surface Solut AG, Oerlikon Balzers, Balzers, Liechtenstein.
    Kolozsvari, S.
    Plansee Composite Mat GmbH, Lechbruck Am See, Germany.
    Paneta, Valentina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Koller, C. M.
    TU Wien, Christian Doppler Lab Applicat Oriented Coating D, Inst Mat Sci & Technol, Vienna, Austria;TU Wien, Inst Mat Sci & Technol, Vienna, Austria.
    Mayrhofer, P. H.
    TU Wien, Christian Doppler Lab Applicat Oriented Coating D, Inst Mat Sci & Technol, Vienna, Austria;TU Wien, Inst Mat Sci & Technol, Vienna, Austria.
    On the phase formation of cathodic arc evaporated Al1-xCrx-based intermetallic coatings and substoichiometric oxides2018In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 352, p. 392-398Article in journal (Refereed)
    Abstract [en]

    The phase evolution of Al1-xCrx-based intermetallic coatings and corresponding substoichiometric oxides grown by cathodic arc evaporation was investigated in order to obtain a better understanding of the relation between oxygen flow rate, Al and Cr content, and structural evolution of the coatings deposited. When using 20 sccm Ar, or 50 sccm O-2, or 100 sccm O-2 per active source (p.a.s.) the cathode reaction zone consists of various intermetallic Al-Cr-compounds, which are in good agreement with the binary Al-Cr phase diagram. This is generally also reflected in the phase composition of the metallic and substoichiometric oxide coatings. The Al-rich compositions, Al0.75Cr0.25 and Al0.70Cr0.30, show a strong tendency for the formation of gamma(1)-Al8Cr5 phases. Mostly, the coating compositions of the metallic constituents of the synthesised intermetallic and substoichiometric oxide coatings deviate from the elemental compositions of the cathode, show enrichment in Cr. This deviation is more pronounced for Cr-rich cathodes using low O-2 flow rates during deposition. The dense columnar structure of the intermetallic coatings (hardness values between 2.5 and 10.2 GPa) turns into a nano-composite-like morphology for depositions with 50 and 100 sccm O-2 p.a.s., which in turn leads to a significant hardness increase up to similar to 24 GPa. Among all coatings investigated, the Cr-rich compositions have higher hardness and denser morphology than the Al-rich layers.

  • 198.
    Dalborg, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    MCNP-modell för beräkning av neutrondos och DPA på reaktortanken vid Ringhals 22013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this report an MCNP (Monte Carlo N-Particle) model is described for the reactor vessel at Ringhals 2. The model is validated against the specific activity in neutron dosimeters, extracted in 1977, 1984 and 1994. The validation showed that the calculations of the model are within the requirements of a maximum of 20 percent uncertainty for every neutron dosimeter except one, extracted after the first cycle. The uncertainty of this cycle was mostly due to the operation data rather than to the MCNP model.

    The model has been used to investigate various questions concerning radiation damage. The reliability of the traditional measure of radiation damage, fast neutron flux (En > 1MeV) has been evaluated.  This has been done by taking the ratio for this and another measure of radiation damage, DPA (Displacement Per Atom), for various positions and layers. The results show good reliability, except for at the outer layers of the vessel wall, where the traditional measure underestimates the radiation damage.

    Inspections are carried out in connection with the change of fuel to investigate any possible cracking on the internal structures of the reactor vessel.  New data on local differences in the radiation of these have therefore been calculated for future evaluations.  This is in order to be able to focus the inspections mainly on those internal parts that are exposed to the highest dose of radiation. An estimation of the neutron dose after 40, 50 and 60 years of operation has been calculated for the surface of the reactor vessel that is being exposed to the highest neutron flux. The result confirms earlier appreciation that the radiation damage to the reactor vessel is not a limiting factor for the future operation of Ringhals 2. The report also presents which surface of the vessel wall that has been exposed to a neutron dose of 1017 n/cm2 for neutrons with En > 1 MeV.

  • 199.
    Davour, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Jacobsson, Staffan Svärd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Image analysis methods for partial defect detection using tomographic images on nuclear fuel assemblies2015Conference paper (Other academic)
    Abstract [en]

    A promising non-destructive assay method for verification of irradiated nuclear fuel is gammatomography, i.e. the use of measurements of the gamma radiation field around a nuclear fuel assembly to reconstruct detailed information about the internal source distribution.

    Typically, tomographic reconstructions result in two-dimensional images of cross sections of the fuel. We demonstrate how such images can be searched for fuel rods using a template matching technique, which is a method commonly used in the field of image analysis. In this case, a template or mask corresponding to the size and shape of a fuel rod is translated across the image in order to find the region with the highest reconstructed activity, which is assumed to correspond to the location of a fuel rod in the image. This is done iteratively, allowing no overlap of the rods. By defining the threshold between background and fuel rod objects in the image, we can identify and count the fuel rods using no other assumptions than the rod radius.

    Thus the rod identification procedure provides a possible means to verify whether all fuel rods arepresent, and it may also be implemented to identify the fuel type of the measured assembly. Theprocedure is robust in cases of irregularities, such as assembly bow or torsion, or the dislocation ofindividual fuel rods in the measured cross section.

    Here we demonstrate fuel rod identification procedure, using authentic images collected with a tomographic measurement device on commercial fuel assemblies. The results show that image analysis can support tomographic partial defect verification of irradiated nuclear fuel assemblies, even on the single fuel rod level.

  • 200.
    Davour, Anna
    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.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. OECD Halden Reactor Project, Halden, Norway.
    Grape, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Holcombe, Scott
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. OECD Halden Reactor Project, Halden, Norway.
    Jansson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Troeng, Mats
    Applying image analysis techniques to tomographic images of irradiated nuclear fuel assemblies2016In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 96, p. 223-229Article in journal (Refereed)
    Abstract [en]

    In this paper we present a set of image analysis techniques used for extraction of information from cross-sectional images of nuclear fuel assemblies, achieved from gamma emission tomography measurements. These techniques are based on template matching, an established method for identifying objects with known properties in images.

    We demonstrate a rod template matching algorithm for identification and counting of the fuel rods present in the image. This technique may be applicable in nuclear safeguards inspections, because of the potential of verifying the presence of all fuel rods, or potentially discovering any that are missing.

    We also demonstrate the accurate determination of the position of a fuel assembly, or parts of the assembly, within the imaged area. Accurate knowledge of the assembly position enables detailed modelling of the gamma transport through the fuel, which in turn is needed to make tomographic reconstructions quantifying the activity in each fuel rod with high precision.

    Using the full gamma energy spectrum, details about the location of different gamma-emitting isotopes within the fuel assembly can be extracted. We also demonstrate the capability to determine the position of supporting parts of the nuclear fuel assembly through their attenuating effect on the gamma rays emitted from the fuel. Altogether this enhances the capabilities of non-destructive nuclear fuel characterization.

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