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1. Ion beam analysis of Li-Sn alloys for fusion applications

Author

Miguel Sales Dias, Miguel B. Costa, Eduardo Alves, Rodrigo Mateus, R.C. da Silva, Norberto Catarino, Mafalda Guedes, Luís Alves, and A.C. Ferro

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Microprobe, Ion beam analysis, Materials science, Intermetallic, Analytical chemistry, 01 natural sciences, 010305 fluids & plasmas, Deuterium, Nuclear reaction analysis, 0103 physical sciences, Melting point, Nuclear fusion, 010306 general physics, Instrumentation
Abstract

The use of liquid Li-Sn alloys for nuclear fusion applications may be hampered by the high melting point of Li-rich intermetallics. Aiming to inhibit their formation, the blend of pure Li (as high as 15 at.%) with pure Sn was controlled via mechanical alloying at room temperature under a dry Ar atmosphere. The depth profiling of Li down to depths near 15–20 μm was followed by nuclear reaction analysis, while elastic backscattering spectroscopy indicated the absence of O within the alloys. Elemental mapping using a nuclear microprobe evidenced the lateral spread of Li in the Sn matrix and identified Cr, Fe and Pb as the only contaminants with contents lower than 0.05 at.%. Despite the competing 2H(3He,p)4He, 6Li(3He,p)8Be, 7Li(3He,p)9Be and 7Li(3He,d)8Be nuclear reactions, retained amounts of deuterium in irradiated surfaces may be quantified with incident 3He+ ion beams in the 0.7 MeV–1.0 MeV energy range.

Published
2021
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2. Deuterium retention on the tungsten-coated divertor tiles of JET ITER-like wall in 2015–2016 campaign

Author

Jyrki Räisänen, A. Lahtinen, Seppo Koivuranta, Jet Contributors, A. Baron-Wiechec, J.P. Coad, Norberto Catarino, Kalle Heinola, Jari Likonen, Eduardo Alves, Anna Widdowson, Materials Physics, and Department of Physics

Subjects
Jet (fluid), Materials science, Fuel retention, Mechanical Engineering, Divertor, Analytical chemistry, chemistry.chemical_element, Plasma, Tungsten, 114 Physical sciences, 01 natural sciences, 010305 fluids & plasmas, Secondary ion mass spectrometry, Nuclear Energy and Engineering, chemistry, Erosion, JET, 0103 physical sciences, General Materials Science, Surface layer, Beryllium, Deposition, 010306 general physics, Deposition (chemistry), Civil and Structural Engineering
Abstract

Tungsten-coated divertor files exposed during the third JET ITER-Like Wall (ILW) campaign in 2015-2016 (ILW-3) were studied with Secondary Ion Mass Spectrometry (SIMS). ILW-3 campaign contained more high-power plasma discharges and longer plasma time than the earlier ILW campaigns. Measurements showed increased beryllium (Be) deposition on the upper inner divertor, whereas on the outer divertor, Be deposition was lower than during the second campaign in 2013-2014 (ILW-2). Increased intensifies of nickel, molybdenum and tungsten were observed at the surface layer of the inner divertor Be dominated deposits. These layers are probably formed during the high-power plasma discharge phase near the end of the ILW-3 campaign. Compared to the earlier campaigns, D retention on the upper inner divertor was observed to on a similar level than after ILW-2, whereas at the lower inner divertor and most parts of the outer divertor, D retention was lower for ILW-3 than ILW-2. D retention was increased at lower part of outer divertor Tile 7, where Be deposition was slightly increased. Probable reason for the reduction is the higher surface temperature of the files due to higher powers used.

Published
2019
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3. Assessing material properties for fusion applications by ion beams

Author

Miguel Sales Dias, Norberto Catarino, I. Jepu, and Eduardo Alves

Subjects
Nuclear and High Energy Physics, Materials science, Divertor, Tantalum, Refractory metals, chemistry.chemical_element, 02 engineering and technology, Tungsten, equipment and supplies, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Fluence, 010305 fluids & plasmas, chemistry, Sputtering, 0103 physical sciences, Irradiation, Composite material, 0210 nano-technology, Instrumentation
Abstract

The plasma-facing materials in the ITER divertor area must withstand unusual events, such as the edge-localized modes (ELMS). At the point when an ELM occurs, up to 30% of the energy can be deposited on the plasma-facing boundary in the form of the heat and particle load causing material loss due to sublimation. Tungsten is a promising candidate as a plasma-facing material in the ITER divertor area since it has a high melting point, good thermal conductivity and low sputtering yield, which minimizes the plasma contamination. However their brittleness at low temperatures which is worsened by irradiation is an issue. One strategy to modulate the properties of tungsten is alloying this element with other refractory metals, such as tantalum that shows higher toughness, lower activation and higher radiation resistance. In the present study tungsten-tantalum alloys (W-Ta) were produced by Ta implantation. The fundamental mechanisms which govern the behaviour of defect dynamics in W-Ta materials under reactor conditions, were simulated by the implantation of He and D. The microstructure observations of the W plates that after single Ta implantation revealed crater-like cavities and a more severe effect after D implantation. The effect increase with the increasing of D fluence. However at fluences higher than 1021D/m the effect is reduced. In addition, blistering was observed in W-Ta plates implanted with He. The D retention in the W-Ta alloys increases with the implanted fluence with tendency for saturation for high fluences. Moreover the results show that D retention is higher after sequential He and D implantation than for single D implantation. The diffractogram of W-Ta alloys implanted with He evidenced the presence of broadened W peaks associated with stress induced by irradiation, which may cause internal stress field resulting in a distortion of the crystal lattice. These irradiation defects can be observed in the D release spectra where three peaks are associated with three types of defects in W and W-Ta implanted with He and D.

Published
2017
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4. Implantation damage formation in a-, c- and m-plane GaN

Author

Ferdinand Scholz, Elke Wendler, Stephan Schwaiger, Norberto Catarino, Katharina Lorenz, Pierre Ruterana, Marie Pierre Chauvat, Andrés Redondo-Cubero, Eduardo Alves, Instituto de Plasmas e Fusão Nuclear [Lisboa] (IPFN), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Institut für Festkörperphysik, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Departamento de Física Aplicada [UAM Madrid], Universidad Autónoma de Madrid (UAM), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institute of Optoelectronic (IO), University of Ulm (UUlm), Universidad Autonoma de Madrid (UAM), and Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Materials science, [PHYS.PHYS]Physics [physics]/Physics [physics], Polymers and Plastics, Metals and Alloys, Nanotechnology, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, Rutherford backscattering spectrometry, Channelling, 01 natural sciences, Crystallographic defect, Molecular physics, Electronic, Optical and Magnetic Materials, Crystal, Ion implantation, Transmission electron microscopy, 0103 physical sciences, [CHIM.CRIS]Chemical Sciences/Cristallography, Ceramics and Composites, Radiation damage, Dislocation, 0210 nano-technology
Abstract

International audience; Epitaxial GaN layers with a-, c- and m-plane surface orientations were implanted with 300 keV Ar-ions at 15 K with fluences ranging from 2 × 1012 to 4 × 1016 at/cm2. Damage build-up proceeds in three steps separated by wide fluence regions where the maximum damage level, measured by in situ Rutherford Backscattering Spectrometry/Channelling, saturates. The three steps occur at similar fluences for the three crystal orientations and similar defect formation rates for the lowest fluences are observed. Surprisingly, the second saturation regime reveals a significantly lower damage level in a-plane layers while m- and c-plane samples suffer more than 4 times higher damage levels. The strong radiation resistance of a-plane GaN was attributed to very efficient dynamic annealing of point defects during the implantation even at 15 K. The migration and aggregation of point defects also lead to distinct defect microstructures as evidenced by transmission electron microscopy. Besides point defects and their clusters the dominant extended defects caused by implantation in c-plane GaN are basal stacking faults while dislocation loops are formed in a-plane material. m-plane GaN presents a mixture of planar defects and dislocation loops after implantation.

Published
2017
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5. Determination of 9 Be(p,p 0 ) 9 Be, 9 Be(p,d 0 ) 8 Be and 9 Be(p,α 0 ) 6 Li cross sections at 150° in the energy range 0.5–2.35 MeV

Author

Eduardo Alves, N.P. Barradas, and Norberto Catarino

Subjects
Nuclear and High Energy Physics, Range (particle radiation), Ion beam analysis, Hydrogen, Proton, Analytical chemistry, chemistry.chemical_element, Plasma, Fusion power, Tungsten, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, chemistry, 0103 physical sciences, Beryllium, Atomic physics, 010306 general physics, Instrumentation
Abstract

Beryllium and Tungsten have been chosen as the new “plasma facing materials” for fusion reactors. Understanding plasma wall interactions and their effects such as erosion and redeposition leading to the formation of alloys from the different materials present in the reactor chamber, is critical to model the retention of hydrogen isotopes by the wall materials. Determining the amount and the depth profile of Be and other elements deposited in the walls is a mandatory requirement in fusion reactors, making the knowledge of the relevant cross sections essential for IBA analysis. In this work we measured the 9Be(p,p0)9Be, 9Be(p,d0)8Be and 9Be(p,α0)6Li cross sections in the energy range 0.5–2.35 MeV, at an angle of 150°.

Published
2016
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6. Fuel retention in JET ITER-Like Wall from post-mortem analysis

Author

N.P. Barradas, Kalle Heinola, Seppo Koivuranta, Eduardo Alves, A. Baron-Wiechec, Jet-Efda Contributors, M. Mayer, Anna Widdowson, S. Brezinsek, P. Coad, Norberto Catarino, Jari Likonen, G. F. Matthews, Per Petersson, and JET-EFDA Contributors

Subjects
Nuclear and High Energy Physics, Ion beam analysis, Chemistry, Divertor, Analytical chemistry, Plasma, 01 natural sciences, 010305 fluids & plasmas, Nuclear Energy and Engineering, Deuterium, Impurity, visual_art, 0103 physical sciences, Limiter, visual_art.visual_art_medium, General Materials Science, Tile, High field, Composite material, 010306 general physics
Abstract

Selected Ion Beam Analysis techniques applicable for detecting deuterium and heavier impurities have been used in the post-mortem analyses of tiles removed after the first JET ITER-Like Wall (JET-ILW) campaign. Over half of the retained fuel was measured in the divertor region. The highest figures for fuel retention were obtained from regions with the thickest deposited layers, i.e. in the inner divertor on top of tile 1 and on the High Field Gap Closure tile, which resides deep in the plasma scrape-off layer. Least retention was found in the main chamber high erosion regions, i.e. in the mid-plane of Inner Wall Guard Limiter. The fuel retention values found typically varied with deposition layer thicknesses. The reported retention values support the observed decrease in fuel retention obtained with gas balance experiments of JET-ILW.

Published
2015
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7. Determination of the 9Be(3He,pi)11B (i=0,1,2,3) cross section at 135° in the energy range 1–2.5MeV

Author

Sérgio Ricardo Magalhães, Rodrigo Mateus, Eduardo Alves, N.P. Barradas, I. Bogdanović Radović, Zdravko Siketić, and Norberto Catarino

Subjects
Nuclear and High Energy Physics, Range (particle radiation), Cross section (physics), Chemistry, Nuclear reaction analysis, Cross sections, 3He, NDF, Atomic physics, Thin film, Instrumentation, Energy (signal processing)
Abstract

The 9 Be( 3 He, p i ) 11 B cross sections for i = 0,1,2,3 at an angle of 135° in the energy range 1–2.5 MeV have been measured using two thin films with different Be thickness at selected energies. The new data extend previous results, that only existed at 90°, 120° and 150° angles, and down to 1.8 MeV, which prevented use of this reaction for samples containing Be at larger depths.

Published
2015
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8. Effects of helium and deuterium irradiation on SPS sintered W–Ta composites at different temperatures

Author

José Lopes, Eduardo Alves, Patricia Almeida Carvalho, V. Livramento, Norberto Catarino, K. Hanada, J.B. Correia, Rodrigo Mateus, J. Rocha, Marta Dias, and N. Franco

Subjects
Nuclear and High Energy Physics, Materials science, Hydride, Tantalum, Sintering, chemistry.chemical_element, Spark plasma sintering, Tungsten, Atmospheric temperature range, Nuclear Energy and Engineering, chemistry, General Materials Science, Irradiation, Composite material, Ball mill
Abstract

Energetic He + and D + ions were implanted into different W–Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta 2 H) formation due to its implications for tritium inventory. Three W–Ta composites with 10 and 20 at.% Ta were prepared from elemental W powder and Ta fibre or powder through low-energy ball milling in argon atmosphere. Spark plasma sintering (SPS) was used as the consolidation process in the temperature range from 1473 to 1873 K. The results obtained from pure elemental samples and composites are similar. However, Ta 2 H is easily formed in pure Ta by using a pre-implantation stage of He + , whereas in W–Ta composites the same reaction is clearly reduced, and it can be inhibited by controlling the sintering temperature.

Published
2013
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9. Comparison of low- and room-temperature damage formation in Ar ion implanted GaN and ZnO

Author

Andrés Redondo-Cubero, Elke Wendler, Werner Wesch, Katharina Lorenz, Eduardo Alves, Norberto Catarino, and A. Yu. Azarov

Subjects
Nuclear and High Energy Physics, Materials science, Ion implantation, Diffusion, Analytical chemistry, Rutherford backscattering spectrometry, Channelling, Instrumentation, Saturation (magnetic), Crystallographic defect, Spectral line, Ion
Abstract

Ar ion implanted GaN and ZnO are studied at 295 K by Rutherford backscattering spectrometry in channelling configuration. Under these conditions in both materials damage formation proceeds in four steps which are characterised by the accumulation of point defects (I), a first saturation of the relative damage concentration at a value well below 10% (II), a second increase of the damage concentration (III) and a second plateau at about 60% for GaN and 40% for ZnO (IV). The results obtained here are compared to those reported previously for Ar ion implantation into these materials performed at 15 K. The main result of our studies is that damage formation is nearly the same for implantation at 295 K and 15 K. This suggests that thermally enhanced defect diffusion is not the main driving force during ion implantation of these materials. The shape of the channelling spectra observed in stages III and IV suggests the existence of both a high concentration of defect clusters and extended defects. The latter are proven to exist after implantation at 295 K. Therefore, there are arguments to conclude that extended defects form already during implantation at 15 K.

Published
2013
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10. Damage formation and recovery in Fe implanted 6H–SiC

Author

Eduardo Alves, Norberto Catarino, Ulrich Wahl, Katharina Lorenz, P.A. Miranda, and J. G. Correia

Subjects
Nuclear and High Energy Physics, Materials science, Annealing (metallurgy), Doping, Wide-bandgap semiconductor, Analytical chemistry, Condensed Matter, Magnetic semiconductor, Ion, Crystallography, chemistry.chemical_compound, Ion implantation, chemistry, Lattice (order), Silicon carbide, Instrumentation
Abstract

Silicon carbide doped with magnetic ions such as Fe, Mn, Ni or Co could make this wide band gap semiconductor part of the diluted magnetic semiconductor family. In this study, we report the implantation of 6H-SiC single crystals with magnetic $^{56}$Fe$^{+}$ ions with an energy of 150 keV. The samples were implanted with 5E14 Fe$^+$/cm$^{2}$ and 1E16 Fe$^+$/cm$^{2}$ at different temperatures to study the damage formation and lattice site location. The samples were subsequently annealed up to 1500°C in vacuum in order to remove the implantation damage. The effect of the annealing was followed by Rutherford Backscattering/Channeling (RBS/C) measurements. The results show that samples implanted above the critical amorphization temperature reveal a high fraction of Fe incorporated into regular sites along the [0001] axis. After the annealing at 1000°C, a maximum fraction of 75%, corresponding to a total of 3.8E14 Fe$^{+}$/cm$^{2}$, was measured in regular sites along the [0001] axis. A comparison is made between the observed annealing behavior and the one measured in low fluence (2E13 cm$^{−2}$) $\beta$- emission channeling experiments using the radioactive isotope $^{59}$Fe (t$_{1/2}$ = 45 d), where the sample was implanted at room temperature and the $\beta$- emission channeling yield was measured by means of a position-sensitive detector.

Published
2012
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11. In Situ Characterization and Modification of β-Ga2 O3 Flakes Using an Ion Micro-Probe

Author

Encarna G. Víllora, Eduardo Alves, Flávia Rocha, Katharina Lorenz, Luís Alves, Marco Peres, Carlos H. Brito Cruz, Kiyoshi Shimamura, Ana G. Silva, and Norberto Catarino

Subjects
010302 applied physics, In situ, Materials science, 02 engineering and technology, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Ion, Characterization (materials science), Chemical engineering, 0103 physical sciences, Materials Chemistry, Irradiation, Electrical and Electronic Engineering, 0210 nano-technology
Published
2018
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12. Global erosion and deposition patterns in JET with the ITER-like wall

Author

M. Mayer, Jet-Efda Contributors, C. Ayres, Kalle Heinola, Eduardo Alves, Marek Rubel, S. Brezinsek, A. Baron-Wiechec, N.P. Barradas, Anna Widdowson, W. Van Renterghem, Norberto Catarino, Jari Likonen, I. Uytdenhouwen, J.P. Coad, G. F. Matthews, Per Petersson, and JET-EFDA Contributors

Subjects
Nuclear and High Energy Physics, Jet (fluid), animal structures, Materials science, Divertor, chemistry.chemical_element, Tungsten, 01 natural sciences, 010305 fluids & plasmas, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, Erosion, Limiter, General Materials Science, Composite material, 010306 general physics, Carbon, Deposition (chemistry), Layer (electronics)
Abstract

A set of Be and W tiles removed after the first ITER-like wall campaigns (JET-ILW) from 2011 to 2012 has been analysed. The results indicate that the primary erosion site is in the main chamber (Be) as in previous carbon campaigns (JET-C). In particular the limiters tiles near the mid-plane are eroded probably during the limiter phases of discharges. W is found at low concentrations on all plasma-facing surfaces of the vessel indicating deposition via plasma transport initially from the W divertor and from main chamber W-coated tiles; there are also traces of Mo (used as an interlayer for these coatings). Deposited films in the inner divertor have a layered structure, and every layer is dominated by Be with some W and O content.

Published
2015
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14. Studies on deuterium retention in W-Ta based materials

Author

K. Hanada, Miguel Sales Dias, N. Pinhão, J.B. Correia, Pedro Barquinha, Vanessa Livramento, Eduardo Alves, Patricia Almeida Carvalho, Norberto Catarino, and Rodrigo Mateus

Subjects
Materials science, Metallurgy, Composite number, Tantalum, Mineralogy, Spark plasma sintering, chemistry.chemical_element, Tungsten, chemistry, Sputtering, Melting point, Instrumentation, Ball mill, Embrittlement
Abstract

The high melting point, high sputtering threshold and low tritium inventory rendered W as a potentially suitable material in fusion devices. The major problem associated with presently available tungsten grades as structural materials is its brittleness at lower temperatures. This is further worsened by irradiation embrittlement. A strategy for ductility improvement is producing a composite, with the brittle W matrix being reinforced by short fibres of tantalum. As Ta is more ductile than W it can therefore divert or stop cracks propagating in the W matrix. In the present research Ta short fibres and powder were used as reinforcement component for W by alloying Ta short fibres or powder in a W powder matrix. The composites were subsequently irradiated with deuterium to assess the retention of this hydrogenic species in the materials.The irradiated composites, with Ta contents of 10 or 20 at%, were produced from pure elemental powders (W-Ta powder composites), and pure W powder and Ta fibre (W-Ta fibre composites) with 100 μm in diameter by low energy ball milling in argon atmosphere. These materials were consolidated via spark plasma sintering (SPS) in the temperature 1200 to 1600 ºC range. Pure W and Ta plates (controls) and W-Ta composites were irradiated with He+ ions (optional pre-implantation step) and D+ ion beams at room temperature with fluences in the 1020-1021 at/m2 range. Blistering and deuterium retention in W and Ta plates and in W-Ta composites were studied with scanning electron microscopy (SEM), X-ray diffraction and thermal desorption analysis. The deuterium concentration was evaluated trough nuclear reaction analysis (NRA) using 0.75 to 2.1 MeV 3He+ beam and the D(3He,p)α reaction.The investigations showed that deuterium irradiation induced microstructural modifications producing blistering in Ta plates as well as in W-Ta composites (Figure 1). These effects increased substantially in the Ta and W-Ta materials with the He pre-implantation step, while blisters have not been observed in the W plates either for D+ or He+ plus D+ implantation. Higher deuterium retention was observed by thermal desorption for the composites than for the W plates. Moreover the present study revealed that D+ trapping in the composites is dependent on the microstructure with higher retention observed for fibers than for powder.This work has been performed under the Contract of Association between EURATOM and Instituto Superior Tecnico. Financial support was also received from the Fundação para a Ciência Tecnologia (FCT) grants with references PTDC/CTM/100163/2008, Pest-OE/SADG/LA0010/2011 and PEST-OE/CTM-UI0084/2011. The authors wish to acknowledge Jorge Rocha the implantation in W-Ta samples.

Published
2013
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15. Helium and deuterium irradiation effects in W-Ta composites produced by pulse plasma compaction

Author

M. Rosinki, Norberto Catarino, Marta Dias, Daniela Nunes, Eduardo Alves, Patricia Almeida Carvalho, J.B. Correia, Elvira Fortunato, and I.D. Nogueira

Subjects
Nuclear and High Energy Physics, Materials science, Scanning electron microscope, Blisters, 02 engineering and technology, 021001 nanoscience & nanotechnology, Rutherford backscattering spectrometry, Microstructure, 01 natural sciences, 7. Clean energy, Focused ion beam, 010305 fluids & plasmas, Nuclear Energy and Engineering, Transmission electron microscopy, Nuclear reaction analysis, 0103 physical sciences, medicine, General Materials Science, Irradiation, medicine.symptom, Composite material, 0210 nano-technology
Abstract

Tungsten-tantalum composites have been envisaged for first-wall components of nuclear fusion reactors; however, changes in their microstructure are expected from severe irradiation with helium and hydrogenic plasma species. In this study, composites were produced from ball milled W powder mixed with 10 at.% Ta fibers through consolidation by pulse plasma compaction. Implantation was carried out at room temperature with He+ (30 keV) or D+ (15 keV) or sequentially with He+ and D+ using ion beams with fluences of 5 × 1021 at/m2. Microstructural changes and deuterium retention in the implanted composites were investigated by scanning electron microscopy, coupled with focused ion beam and energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Rutherford backscattering spectrometry and nuclear reaction analysis. The composite materials consisted of Ta fibers dispersed in a nanostructured W matrix, with Ta2O5 layers at the interfacial regions. The Ta and Ta2O5 surfaces exhibited blisters after He+ implantation and subsequent D+ implantation worsened the blistering behavior of Ta2O5. Swelling was also pronounced in Ta2O5 where large blisters exhibited an internal nanometer-sized fuzz structure. Transmission electron microscopy revealed an extensive presence of dislocations in the metallic phases after the sequential implantation, while a relatively low density of defects was detected in Ta2O5. This behavior may be partially justified by a shielding effect from the blisters and fuzz structure developed progressively during implantation. The tungsten peaks in the X-ray diffractograms were markedly shifted after He+ implantation, and even more so after the sequential implantation, which is in agreement with the increased D retention inferred from nuclear reaction analysis.

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16. Sintering and irradiation of copper-based high entropy alloys for nuclear fusion

Author

António Pereira Gonçalves, Magdalena Galatanu, Eduardo Alves, Paula Ferreira, Norberto Catarino, F. Antão, Andrei Galatanu, Marta Dias, R.C. da Silva, and J.B. Correia

Subjects
Materials science, Scanning electron microscope, Mechanical Engineering, High entropy alloys, Analytical chemistry, Spark plasma sintering, Sintering, chemistry.chemical_element, Tungsten, Microstructure, Thermal diffusivity, 7. Clean energy, 01 natural sciences, Copper, 010305 fluids & plasmas, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, General Materials Science, 010306 general physics, Civil and Structural Engineering
Abstract

In this study, CuxCrFeTiV (x = 0.21, 0.44, 1 and 1.7 M ratio) high entropy alloys have been devised for thermal barriers between the plasma facing tungsten tiles and the copper-based heat sink in the first wall of nuclear fusion reactors. The high entropy alloys were produced by ball milling the elemental powders, followed by consolidation with spark plasma sintering. Irradiation of the equiatomic CuCrFeTiV sample was carried out at room temperature with Ar+ (300 keV) beams with a fluence of 3 × 1020 at/m2. Structural changes prior and after irradiation were investigated by scanning electron microscopy, coupled with energy dispersive X-ray spectroscopy, X-ray diffraction and thermal diffusivity. Preliminary results showed the presence of heterogenous and multiphasic microstructures in all samples. Moreover, with the increase of the Cu content it is possible to observe the formation of Cu-rich structures. The diffractogram of the CuCrFeTiV sample revealed major peaks of a BCC crystal structure and minor peaks of a FCC crystal structure. In addition, after irradiation no modifications in the CuCrFeTiV microstructure or in the diffractogram were observed.

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17. Time-resolved deposition in the remote region of the JET-ILW divertor: measurements and modelling

Author

Alexander Lukin, Eduardo Alves, Stefan Matejcik, Aleksandra Baron-Wiechec, Soare Sorin, Francesco Romanelli, Kalle Heinola, Norberto Catarino, Anna Widdowson, Bohdan Bieg, Vladislav Plyusnin, José Vicente, Alberto Loarte, Axel Jardin, Rajnikant Makwana, CHIARA MARCHETTO, Marco Wischmeier, William Tang, Choong-Seock Chang, and Manuel Garcia-munoz

Subjects
Jet (fluid), Nuclear engineering, Divertor, Fusion power, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, 0103 physical sciences, Environmental science, Deposition (phase transition), 010306 general physics, Mathematical Physics
Abstract

One crucial requirement for the development of fusion power is to know where, and how much, impurities collect in the machine, and how much of the fuelling isotope tritium will be trapped therein. ...

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18. Deep neural networks for plasma tomography with applications to JET and COMPASS

Author

J. Denis, M. Tardocchi, Kiptily, M. Koubiti, M. Ghate, R. Michling, G. De Masi, T. Tala, M. Bassan, R. McAdams, S. Dowson, Antoine Merle, Seppo Koivuranta, O. J. Kwon, S. Mahesan, P. Sparapani, A. Malaquias, M. Tsalas, Gennady V. Miloshevsky, M. Vecsei, Michal Stano, E. Lerche, Štefan Matejčík, Piergiorgio Sonato, S. D. Pinches, A. Dal Molin, O. McCormack, B. Colling, F. Mink, Ph. Mertens, P. Drewelow, Nuno Cruz, D. Iglesias, Alessandro Zocco, K. Rathod, S. Collins, F. Koechl, James Buchanan, Andrew West, Francesco Maviglia, E. Stefanikova, David Taylor, B. Graham, T. Lunt, S. Meshchaninov, Arturo Buscarino, G. L. Ravera, Maide Bucolo, J. P. Thomas, S. Foley, B. Wakeling, N. Ashikawa, D. W. Robson, N. J. Conway, V. P. Lo Schiavo, Stefan Buller, Sergey Popovichev, M. Saleem, Jorge Luis Rodriguez, M. Wheatley, Gabriele Croci, Hugo Bufferand, J.F. Artaud, R. C. Felton, O. Kovanda, D. Hepple, K. Dylst, Gabor Szepesi, M. Oberkofler, G.J. van Rooij, N. Teplova, Istvan Cziegler, K. K. Kirov, S. Vartanian, Y. Xue, D. Nina, J. Bernardo, Lorenzo Figini, Guglielmo Rubinacci, Peter Lang, R. Scannell, N. C. Hawkes, P. Denner, Istvan Pusztai, D. D. Carvalho, Salvatore Ventre, A. Lescinskis, Afanasev, C. Hamlyn-Harris, Panagiotis Tolias, R. Vale, T. O'Gorman, S. Lesnoj, I.E. Day, Karol Malinowski, D. Carralero, N. Balshaw, Massimo Angelone, Michaele Freisinger, I. Monakhov, Jesús Vega, Jonathan Citrin, Antti Hakola, H. Patten, P. A. Simmons, Y. Austin, Sehyun Kwak, J. Regana, Rohde, T. Eich, A. Alkseev, R. Lawless, C. G. Elsmore, Fusco, S. Hacquin, S. A. Silburn, A. Fernades, Luigi Fortuna, P. Bunting, R. Sartori, Yuji Hatano, D. Borodin, L. Colas, Daniele Marocco, M. Lennholm, Carlo Sozzi, J. J. Rasmussen, P. McCullen, Tommy Ahlgren, A. Kirschner, Thomas Johnson, M. Rack, Göran Ericsson, Hans Nordman, Jakub Bielecki, P. Merriman, M. Cavedon, G. Hermon, Geert Verdoolaege, K. J. Gibson, Daisuke Nishijima, R. Clarkson, Fuchs, M. Tomes, R. Zagórski, Gerald Pintsuk, W. Higginson, Daniel F. Valcarcel, R. Mooney, K. Dawson, A. Tallargio, T.H. Osborne, P. J. Carvalho, M. Gethins, R. Dux, Pierre Dumortier, G. Urbanczyk, Inessa Bolshakova, R. King, B. Tal, Daniel Tegnered, J. W. Coenen, Leena Aho-Mantila, Eva Belonohy, S. Schmuck, Kai Nordlund, Grégoire Hornung, G. Tvalashvili, M. De Bock, Y. Baranov, G. De Tommasi, A. Urban, L. Forsythe, I. Zychor, J. Dobrashian, E. Clark, Paolo Arena, Alessia Santucci, Ivan Lupelli, S. Nowak, M. Curuia, Jonathan Graves, J. C. Hillesheim, Claudio Verona, Zoita, S. Moon, C. Castaldo, A.V. Stephen, Karl Schmid, A. Sahlberg, C. Di Troia, R. Woodley, L. Garzotti, D. Sandiford, Matthew M. Knight, Juho Leppänen, S. Emery, O. G. Pompilian, M. Goniche, C. Luna, M. Mayer, M. Baruzzo, A. Weckmann, M. Kempenaars, S. Hazel, Fabio Pisano, Claudia Corradino, A. G. Meigs, P. Leichauer, S. Potzel, Stéphane Devaux, C. Piron, G. Saibene, David A Rasmussen, Bruce Lipschultz, A. Di Siena, E. Lazzaro, J. Deane, C. Meadowcroft, C. J. Rapson, K.-D. Zastrow, Ph. Duckworth, Tom Wauters, F. Nabais, T. Goerler, D. Brunetti, R. Ellis, David Moulton, L. Jones, E. Delabie, Anna Salmi, Luciano Bertalot, G. Burroughes, B. Kos, Laurent Marot, Daniel Primetzhofer, I Miron, N. Lam, F. Napoli, S. Rowe, E. Pajuste, Choong-Seock Chang, R.P. Doerner, D. Silvagni, C. Guillemaut, S. Warder, A.J. Thornton, Matthew Carr, A. Dempsey, Jorge Morales, Pramit Dutta, J. L. Herfindal, S. Maruyama, P. Camp, X. Lefebvre, Ye. O. Kazakov, Andrea G. Chiariello, Gabriele Manduchi, Andre Neto, T. Powell, J. Griffiths, José Vicente, C. Barcellona, J. Hobirk, F. Clairet, L. Xiang, Dirk Reiser, H. Bergsåker, I. Duran, G. Giacometti, M. Kalsey, David Tskhakaya, A. Martin de Aguilera, T. Dittmar, Edmund Highcock, I. Uytdenhouwen, S. Soare, Giuseppe Prestopino, L. Chôné, W. Davis, G. De Temmerman, Basiuk, G. Learoyd, C. Guerard, A. Klix, M. Incelli, B. Viola, R. J. Robins, A. Burckhart, W. Leysen, Jochen Linke, M. Oberparleiter, A. Murari, M. Sertoli, S. D. Scott, A. Lazaros, R. Dejarnac, P. Buratti, H.R. Strauss, G. T. A. Huijsmans, Hajime Urano, Justine M. Kent, A. Kallenbach, D. Fagan, D. S. Darrow, Benedikt Geiger, A. Wynn, X. Sáez, B. Beckett, Horacio Fernandes, G. Ferro, B. Alper, George Wilkie, A. Uccello, T.C. Luce, S. Zoletnik, Petrzilka, Fulvio Auriemma, D. Guard, A. Ho, R. Henriques, I. T. Chapman, D. Butcher, Ph. Maquet, C. Crapper, S. Murphy, C. Ham, D. Brennan, S. Knott, Krasilnikov, D. Kogut, Cédric Pardanaud, K. Galazka, Nicolò Marconato, Daniele Bonfiglio, M. Sos, E. Militello-Asp, Nesenevich, Sean Conroy, S. Hall, L. F. Ruchko, L. Laguardia, O. Marchuk, F.P. Orsitto, I. S. Nedzelskiy, Eva Macusova, E. Andersson Sundén, C. Ayres, R. Prakash, C. Giroud, M. Parsons, R. Rodionov, M. Marin, A. P. Vadgama, A. Reed, Jacob Eriksson, P. Macheta, R. Neu, J. Orszagh, L. Gil, Riccardo Maggiora, M. Peterka, P. Devynck, M. Price, J. Likonen, Andrew M. Edwards, P. Dalgliesh, I. Vinyar, Andrea Malizia, A. Brett, Jane Johnston, A. Kappatou, P. Blatchford, B. Lloyd, P. Vincenzi, A. Mauriya, A. Garcia-Carrasco, Z. Stancar, D. B. Gin, Gediminas Stankunas, J. Edwards, Giuseppe Ambrosino, A. Goodyear, M. Lungaroni, M. Gardener, R.A. Pitts, Svetlana V. Ratynskaia, E. Ivings, Marek Rubel, L. Calacci, Ivo S. Carvalho, M. Afzal, M. Gherendi, D. Schworer, C. Watts, A. M. Messiaen, E. Safi, P. David, A. Petre, J. Uljanovs, U. von Toussaint, H. Greuner, D. Del Sarto, A.C.A. Figueiredo, D. Gallart, R. Bilato, M. Enachescu, P. Monaghan, M. S. J. Rainford, A. Boboc, M. Reinhart, Hiroyasu Utoh, B. P. Duval, L. Hackett, M. Halitovs, G. De Dominici, B. Lomanowski, P. Cahyna, Aslanyan, T. May-Smith, M. Richiusa, A. Goussarov, M. Okabayashi, R. Howell, T. Tadic, M. E. Manso, J. F. Rivero-Rodriguez, Wayne Arter, Ivan Calvo, U. Losada, H. Weisen, A. Teplukhina, Marica Rebai, R. Andrews, C. H. A. Hogben, M. Klas, A. E. Shevelev, J. McKehon, F. Reimold, Enrico Zilli, R. Maingi, M.F. Stamp, A. Rakha, H. T. Kim, D. Ciric, Eric Nardon, A. Somers, I. Igaune, E. Laszynska, S. Saarelma, A. Cullen, Mǎdǎlina Vlad, D. Nodwell, S. Griph, T. Donne, T. Boyce, M. Tyshchenko, Paulo Carvalho, Elena Bruno, Ion E. Stamatelatos, A. Patel, E. de la Luna, F. Causa, Robin Barnsley, Michael Lehnen, F. Belli, N. Jones, B. Bauvir, M. Tokitani, I. Turner, Y. Zhou, J. Simpson, A. Vitins, D. Rendell, Alberto Milocco, Benjamin P. Brown, F.G. Rimini, C. Lamb, V. Thompson, E. Alessi, S. Arshad, J. Rzadkiewicz, P. Prior, J. Moran, S. D. A. Reyes Cortes, Igor Bykov, M. Weiszflog, Annette M. Hynes, Gennady Sergienko, J. Lönnroth, T. C. Hender, M.-L. Mayoral, Mattia Frasca, R. Coelho, J-J Honore, A. Jackson, A. Sirinelli, M. D. Axton, Hyun-Tae Kim, F. P. Keenan, H. J. Boyer, Elisabeth Rachlew, T. Szabolics, J. Ongena, Braic, Sandra C. Chapman, Anders Nielsen, John E. Marsh, J. Jansons, S. Gloeggler, Nengchao Wang, Naulin, M. Porton, D. Falie, P. Welch, G. T. Jones, N. Fil, M. Vincent, U. Kruezi, R. Pereira, L. Horvath, M. F. F. Nave, Lorella Carraro, N. Fonnesu, Davide Flammini, P. V. Edappala, G. M. D. Hogeweij, K. Krieger, P. Card, G. Poulipoulis, W. Studholme, Didier Mazon, T. Odupitan, D. Young, F. J. Casson, N. Muthusonai, I. Jepu, Olivier Sauter, Dimitri Voltolina, Sara Carcangiu, C. Reux, Irena Ivanova-Stanik, D. Tskhakaya Jun, O. Bogar, E. Viezzer, Shane Cooper, Fabio Villone, Florin Spineanu, H. Doerk, E. Cecil, J. Goff, F. Nespoli, F. Schluck, G. Ciraolo, Jennifer M. Lehmann, Jan Mlynar, H. J. C. Oliver, M. Marinucci, N. Krawczyk, J. Buch, M. Dreval, G. Possnert, C. Angioni, C. P. Lungu, Marco Ariola, S. Breton, Christopher N. Bowman, A. Kundu, J. Mailloux, I. Stepanov, D. Sprada, J. Zacks, G. Ramogida, E. Wolfrum, N.W. Eidietis, A. Pires dos Reis, Barbara Cannas, Robert E. Grove, A. Huber, Giuliana Sias, A. Baron Wiechec, Markus Airila, M. Berry, P. Huynh, R. Kovaldins, R. Bastow, Darren Price, S. Abduallev, P. Tsavalas, N. Aiba, Plyusnin, Ion Tiseanu, James Williams, M. Beckers, M. Weiland, S.N. Gerasimov, Alessandra Fanni, L. D. Horton, T. Xu, L. Joita, N. Reid, D. Zarzoso Fernandez, D. I. Refy, Jerry Hughes, Clarisse Bourdelle, J. E. Boom, G. Hancu, K. M. Aggarwal, F. Crisanti, M. Poradziński, A. Loarte, P. Vallejos Olivares, T. Mrowetz, Teddy Craciunescu, R. Guirlet, M. Valentinuzzi, J. Stephens, J. Stober, Michael Barnes, Isabel L. Nunes, Mario Pillon, P. Batistoni, G. Verona Rinati, Fabio Moro, R. Lucock, R. Olney, Jari Varje, B. Butler, A. Mariani, M. Hamed, Skvara, C. Terry, Larisa Baumane, T. Alarcon, Mike Kotschenreuther, T. M. Biewer, O. Hemming, N. Marcenko, Z. Kollo, B. Slade, J. Garcia, T. R. Blackman, Simone Peruzzo, N. den Harder, S. Ng, P. Siren, K. G. McClements, Rita Lorenzini, Y. Yakovenko, Lorenzo Frassinetti, J. Hawes, A. Kirk, C. Noble, Nicola Bonanomi, Y. Martynova, A.E. Shumack, F. Di Maio, H. R. Koslowski, N. Pomaro, G. Nemtsev, M. I. K. Santala, Richard George, E. Giovannozzi, T. Giegerich, C. Woodley, G. Pucella, D. Hopley, P.J. Knight, Michela Gelfusa, Francesca Poli, G. Petravich, G. Kocsis, S. Lanthaler, J. A. Wilson, D. Coombs, F. Köchl, G. Stables, Silvia Spagnolo, D. Rigamonti, W. Van Renterghem, Mike Dunne, H. Betar, W. Pires de Sa, Stjepko Fazinić, M. Nocente, G. Birkenmeier, L. Avotina, A. Horton, P. Heesterman, Larry R. Baylor, C. Stavrou, L. Appel, Amosov, J. Fessey, J. Flanagan, C. Paz Soldan, G. Kaveney, R. Young, Shimpei Futatani, U. Samm, R. Naish, P. Strand, E. Lascas Neto, S. Wheeler, Daisuke Shiraki, S. P. Hotchin, D. M. Witts, A. Cobalt, C. Waldon, Davide Galassi, I. Jenkins, S. Panja, C. Gurl, A. Lukin, R. Albanese, Andrea Pavone, A. Davies, J. Hawkins, N. Vianello, C. Besiliu, F. Domptail, Bruno Santos, Y. Li, T. Kaltiaisenaho, O. N. Kent, X. Litaudon, B. Lescinskis, M. Faitsch, Otto Asunta, F. Eriksson, Pericoli, M. Beldishevski, G.A. Rattá, C. D. Challis, Z. Ghani, M. Juvonen, A. C. C. Sips, João M. C. Sousa, Boris Breizman, P. Finburg, Henrik Sjöstrand, Slawomir Jednorog, Ewa Kowalska-Strzęciwilk, A. Martin, R. O. Dendy, B. Lepiavko, D. Croft, Goloborod'ko, A. V. Krasilnikov, M. Wischmeier, K. Gal, R. Ragona, Petter Ström, N. Parsons, G. Calabrò, Jean-Stéphane Joly, A. Capat, Linwei Li, T. Nakano, Paulo Rodrigues, L. Moser, João P. S. Bizarro, L. Piron, K. Pepperell, P. Aleynikov, Ambrogio Fasoli, S.-P. Pehkonen, Giuseppe Gorini, C. Taliercio, M. E. Puiatti, J. Svensson, H. R. Wilson, John Wright, S. Wiesen, O. Asztalos, R.V. Budny, A. Withycombe, P. Piovesan, Jonathan Gaspar, B. D. Stevens, P. Trimble, Vinodh Bandaru, F. S. Zaitsev, H. Sheikh, G. F. Matthews, Daniele Carnevale, K. Schoepf, L. McNamee, A. Czarnecka, P. Blanchard, Erik Fransson, J.P. Coad, Daniel Dunai, Carolina Björkas, A. Manzanares, M. Reich, A. Lahtinen, L. Giacomelli, Mirko Salewski, E. de la Cal, T. D. V. Haupt, T.T.C. Jones, M. Anghel, Kyriakos Hizanidis, J. M. Fontdecaba, Huber, A. Shaw, A. Cufar, A. Muraro, M. Clark, A. Meakins, Roland Sabot, A. Owen, K. Valerii, A. L. Esquisabel, Petr Vondracek, Maria Teresa Porfiri, Walid Helou, S. E. Sharapov, D. Terranova, M. Skiba, Konstantina Mergia, Frank Leipold, Francisco L. Tabarés, M. Zerbini, Ken W Bell, Marco Marinelli, Marco Riva, R. Martone, Bobkov, B. Magesh, A. Ash, Parail, M. Hook, Amanda Hubbard, Silvio Ceccuzzi, Ulrich Fischer, G. Liu, Nick Walkden, R. Otin, P. Santa, P. Abreu, Demerdzhiev, Roberto Zanino, T. Spelzini, António J.N. Batista, P. G. Smith, L. Meneses, S. S. Medley, M. J. Mantsinen, K. Vasava, G. Gervasini, Surya K. Pathak, Kristel Crombé, G. Ellwood, P. Raj, Robert Hager, Ch. Linsmeier, C. Stokes, Petra Bilkova, M. Groth, G. Pautasso, C. R. Nobs, S. Sridhar, P. Chmielewski, David Hatch, Luca Boncagni, I. Balboa, C. Stan-Sion, Nobuyuki Asakura, R. McKean, L. Pigatto, João Figueiredo, Roberto Cavazzana, Juri Romazanov, M. Beurskens, C. Christopher Klepper, Maryna Chernyshova, O. Biletskyi, D. Karkinsky, A. Eksaeva, S. Dalley, Pasquale Gaudio, J. Benayas, J. Dankowski, S. Korolczuk, R. Buckingham, F. Parra Diaz, E. Wang, A. Cardinali, J. Naish, R. O. Pavlichenko, Kalle Heinola, Hiroshi Tojo, Miles M. Turner, Brett Chapman, A. Lyssoivan, F. Militello, E. Matveeva, T. Kobuchi, I. Ksiazek, P. Bohm, Cody Jones, W. Yanling, T. Jackson, P. Gohil, D. Alegre, Tim D. Bohm, F. Jaulmes, L. Zakharov, Peter J. Pool, C.G. Lowry, M. Passeri, D. Testa, Igor Lengar, A. Formisano, C. M. Roach, A. Hjalmarsson, A. Drenik, S. Meiter, William Tang, Carlos B. da Silva, Diogo R. Ferreira, P. J. Lomas, M. McHardy, Gunta Kizane, Angela Busse, S. Jachmich, Corneliu Porosnicu, Stanislas Pamela, Yavorskij, Eduardo Alves, Saskia Mordijck, Boniface Nkonga, J. Morris, Dean A. J. Whittaker, S. Ertmer, A. Hollingsworth, T. Barnard, R. Tatali, S. Reynolds, S. Mistry, Sergio Galeani, Torbjörn Hellsten, V.S. Neverov, David Dickinson, T. M. Huddleston, D. Baiao, F. Salzedas, D. Willoughby, M. Tripsky, Emmanuele Peluso, J. R. Harrison, C. Mazzotta, R. Zarins, M. Maslov, X. Bonnin, T. E. Gebhart, S. Fietz, K. Flinders, C. Hidalgo, Yann Corre, Aqsa Shabbir, A. B. Kukushkin, A. Shepherd, M.L. Walker, R. Clay, T. Vasilopoulou, Paolo Innocente, I. H. Coffey, P. Lalousis, Italo Predebon, R. Bravanec, P. Papp, D. Sytnykov, Ewa Pawelec, M. Bernert, G. Corrigan, Lutsenko, M. Romanelli, Gergely Papp, S. Romanelli, R. Salmon, J. Risner, M. T. Ogawa, A. M. Whitehead, E. Fable, H. Dabirikhah, Juan Manuel López, M. Turnyanskiy, A. Baciero, S. Meigh, M. Garcia-Munoz, Massimiliano Mattei, J.-M. Noterdaeme, N. Hamilton, S. Minucci, I Wilson, A. Muir, A. V. Chankin, C. Clements, Matthias Hoelzl, Francesco Romanelli, S. Gee, R. J. E. Smith, P. de Vries, L. Fittill, S. Menmuir, K. Cave-Ayland, P. Curson, Richard Fridström, D. Grist, S. A. Robinson, Rodney Walker, Michael Loughlin, S. Aleiferis, W. Broeckx, Clayton E. Myers, S. F. Smith, D. Harting, W. Zwingmann, F. Binda, Mark R. Gilbert, Rajnikant Makwana, Richard Goulding, D. Van Eester, I. Voitsekhovitch, M. Bowden, I. Kodeli, Tomasz Czarski, Peter Hawkins, S. S. Henderson, M. Koeppen, D. Ricci, Ondrej Ficker, Carl Hellesen, D. Yadikin, Fabio Subba, Luka Snoj, Anthony Laing, E. R. Solano, M. Stephen, P. Staniec, C. Appelbee, M. Newman, Susan Leerink, M. Nicassio, P. P. Pereira Puglia, M. Brombin, Wouter Tierens, C. Perez von Thun, Cédric Boulbe, Ya. I. Kolesnichenko, Taina Kurki-Suonio, S. Hallworth-Cook, R. P. Johnson, B. B. Carvalho, Anna Widdowson, Alessandro Pau, R. Price, B. Gonçalves, D. L. Keeling, Kazantzidis, Michael Fitzgerald, M. Hughes, K. D. Lawson, M. Brix, Raffaele Fresa, Juha Karhunen, S. Esquembri, K. Purahoo, Matthew Reinke, Gerd Meisl, M. Valovic, J. Horacek, D. King, H. Maier, Philipps, Kenji Tanaka, M. Kresina, M. Valisa, L. Omoregie, Gábor Cseh, Seppo Sipilä, Scott W. Mosher, Filippo Sartori, J. Kaniewski, Jan Weiland, Giuseppe Chitarin, Coccorese, A. R. Field, P. Beaumont, Robert Skilton, D. C. Campling, Mitul Abhangi, S. Villari, Roberta Lima Gomes, G. D. Ewart, S. Wray, A. Broslawski, A. Sinha, Roberto Paccagnella, S. Hollis, R. D. Wood, Albert Gutierrez-Milla, E. Jonasson, L.-G. Eriksson, R. Leach, L. W. Packer, M. Vuksic, H. J. Sun, C. Marchetto, Giuseppe Telesca, Dieter Leichtle, S. Cramp, Blaise Faugeras, M. Allinson, Yannis Kominis, R. Normanton, H. J. Leggate, Francesco Ghezzi, T. Schlummer, Tommaso Bolzonella, Jorge Ferreira, M. J. Walsh, C. Day, Philipp Drews, Steven J. Meitner, M. D. J. Bright, Per Petersson, D. L. Hillis, M. Webb, P. Wright, C. F. Maggi, B. Sieglin, A. Farahani, J. Strachan, M. Muraglia, M. Cecconello, F. Durodié, D. Callaghan, J. Waterhouse, R. J. Dumont, Sara Moradi, Patrick J. McCarthy, S. Feng, M. Balden, M. Kaufman, R. Warren, Brian Grierson, Harry M. Meyer, S.C. Bradnam, D. Kinna, A. Krivska, M. Lungu, E. Suchkov, A. Kantor, D. Conka, C. Penot, A. Zarins, Pierre Manas, D. F. Gear, J. Callaghan, L. Barrera Orte, Tomas Markovic, Yu Gao, A. Lunniss, Z. Vizvary, E. Khilkevich, Th. Puetterich, Dmitry Matveev, E. Perelli Cippo, T. Owen, N. Imazawa, A. Silva, H. P. Summers, Norberto Catarino, Roberto Pasqualotto, P. Muscat, K. Keogh, Ricardo Magnus Osorio Galvao, P. Carman, M. Leyland, E. Veshchev, A. de Castro, M. Gruca, D. C. McDonald, L. Moreira, J. W. Banks, Sanjeev Ranjan, N. Sutton, Iris D. Young, Martin Imrisek, W. Zhang, J. K. Blackburn, Moiseenko, A. Parsloe, T. Loarer, D. N. Borba, S.J. Wukitch, D. P. Coster, J. Penzo, Jose Ramon Martin-Solis, P. Mantica, N. Bekris, M. G. O'Mullane, S. E. Dorling, Yunfeng Liang, S. Gulati, Roberto Ambrosino, J. Schweinzer, Cocilovo, D. Douai, M. A. Henderson, T. Suzuki, Gianluca Rubino, A. Peackoc, Yann Camenen, Y. Miyoshi, Ph. Jacquet, H. T. Lambertz, E. Tholerus, C. Sommariva, Prajapati, Yannick Marandet, F. Hasenbeck, Faa Federico Felici, M. Buckley, Kenneth Hammond, Daniele Milanesio, Cristian Ruset, Katsumichi Hoshino, D. Frigione, D. Chandra, I. Borodkina, P. Dinca, S. Brezinsek, J. Stallard, H. G. Esser, Matthew Sibbald, S. Knipe, Jorge Estrela da Silva, Kensaku Kamiya, P. A. Coates, J. C. Giacalone, Alfredo Pironti, Carvalho, D. D., Ferreira, D. R., Carvalho, P. J., Imrisek, M., Mlynar, J., Fernandes, H., and Formisano, A.

Subjects
Computer science, Feature extraction, Image processing, Computerized Tomography (CT) and Computed Radiography (CR), Plasma diagnostics - interferometry, spectroscopy and imaging, 01 natural sciences, Convolutional neural network, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Compass, Plasma diagnostics-interferometry, spectroscopy and imaging, 0103 physical sciences, Computer vision, Instrumentation, Mathematical Physics, Jet (fluid), Contextual image classification, 010308 nuclear & particles physics, business.industry, Cognitive neuroscience of visual object recognition, Plasma diagnostics - interferometry spectroscopy and imaging, Tomography, Artificial intelligence, business, plasma diagnostics - interferometry, spectroscopy and imaging
Abstract

Convolutional neural networks (CNNs) have found applications in many image processing tasks, such as feature extraction, image classification, and object recognition. It has also been shown that the inverse of CNNs, so- called deconvolutional neural networks, can be used for inverse problems such as plasma tomography. In essence, plasma tomography consists in reconstructing the 2D plasma profile on a poloidal cross-section of a fusion device, based on line-integrated measurements from multiple radiation detectors. Since the reconstruction process is computationally intensive, a deconvolutional neural network trained to produce the same results will yield a significant computational speedup, at the expense of a small error which can be assessed using different metrics. In this work, we discuss the design principles behind such networks, including the use of multiple layers, how they can be stacked, and how their dimensions can be tuned according to the number of detectors and the desired tomographic resolution for a given fusion device. We describe the application of such networks at JET and COMPASS, where at JET we use the bolometer system, and at COMPASS we use the soft X-ray diagnostic based on photodiode arrays.

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