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Publications (10 of 211) Show all publications
Oya, Y., Masuzaki, S., Tokitani, M., Azuma, K., Oyaidzu, M., Isobe, K., . . . contributors, J. (2018). Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall. Fusion engineering and design, 132, 24-28
Open this publication in new window or tab >>Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall
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2018 (English)In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 132, p. 24-28Article in journal (Refereed) Published
Abstract [en]

To understand the fuel retention mechanism correlation of surface chemical states and hydrogen isotope retention behavior determined by XPS (X-ray photoelectron spectroscopy) and TDS (Thermal desorption spectroscopy), respectively, for JET ITER-Like Wall samples from operational period 2011–2012 were investigated. It was found that the deposition layer was formed on the upper part of the inner vertical divertor area. At the inner plasma strike point region, the original surface materials, W or Mo, were found, indicating to an erosion-dominated region, but deposition of impurities was also found. Higher heat load would induce the formation of metal carbide. At the outer horizontal divertor tile, mixed material layer was formed with iron as an impurity. TDS showed the H and D desorption behavior and the major D desorption temperature for the upper part of the inner vertical tile was located at 370 °C and 530 °C. At the strike point region, the D desorption temperature was clearly shifted toward higher release temperatures, indicating the stabilization of D trapping by higher heat load.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Hydrogen isotope behavior, JET-ILW, Plasma wall interactions
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-228730 (URN)10.1016/j.fusengdes.2018.04.124 (DOI)2-s2.0-85046629650 (Scopus ID)
Funder
EU, European Research Council
Note

QC 20180529

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-05-29Bibliographically approved
Ström, P., Petersson, P., Rubel, M. & Possnert, G. (2018). Erratum: "A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis" [Rev. Sci. Instrum. 87, 103303 (2016)]. Review of Scientific Instruments, 89(4), Article ID 049901.
Open this publication in new window or tab >>Erratum: "A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis" [Rev. Sci. Instrum. 87, 103303 (2016)]
2018 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 89, no 4, article id 049901Article in journal (Refereed) Published
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-227781 (URN)10.1063/1.5030502 (DOI)000431139400078 ()29716341 (PubMedID)2-s2.0-85045335587 (Scopus ID)
Note

QC 201805014

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-06-01Bibliographically approved
Fazinic, S., Tadic, T., Vuksic, M., Rubel, M., Petersson, P., Fortuna-Zalesna, E. & Widdowson, A. (2018). Ion Microbeam Analyses of Dust Particles and Codeposits from JET with the ITER-Like Wall. Analytical Chemistry, 90(9), 5744-5752
Open this publication in new window or tab >>Ion Microbeam Analyses of Dust Particles and Codeposits from JET with the ITER-Like Wall
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2018 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 9, p. 5744-5752Article in journal (Refereed) Published
Abstract [en]

Generation of metal dust in the JET tokamak with the ITER-like wall (ILW) is a topic of vital interest to next-step fusion devices because of safety issues with plasma operation. Simultaneous Nuclear Reaction Analysis (NRA) and Particle Induced X-ray Emission (PIXE) with a focused four MeV He-3 microbeam was used to determine the composition of dust particles related to the JET operation with the ILW. The focus was on "Be-rich particles" collected from the deposition zone on the inner divertor tile. The particles found are composed of a mix of codeposited species up to 120 m in size with a thickness of 30-40 mu m, The main constituents are D from the fusion fuel, Be and W from the main plasma-facing components, and Ni and Cr from the Inconel grills of the antennas for auxiliary plasma heating. Elemental concentrations were estimated by iterative NRA-PIXE analysis. Two types of dust particles were found: (i) larger Be-rich particles with Be concentrations above 90 at% with a deuterium presence of up to 3.4 at% and containing Ni (1-3 at%), Cr (0.4-0.8 at%), W (0.2-0.9 at%), Fe (0.3-0.6 at%), and Cu and Ti in lower concentrations and (ii) small particles rich in Al and/or Si that were in some cases accompanied by other elements, such as Fe, Cu, or Ti or W and Mo.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-228440 (URN)10.1021/acs.analchem.8b00073 (DOI)000431464400032 ()29620878 (PubMedID)
Note

QC 20180529

Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2018-05-29Bibliographically approved
Brezinsek, S., Wirtz, M., Dorrow-Gesprach, D., Loewenhoff, T. & Rubel, M. (2017). 16th International Conference on Plasma-Facing Materials and Components for Fusion Applications. Physica Scripta, T170, Article ID 010201.
Open this publication in new window or tab >>16th International Conference on Plasma-Facing Materials and Components for Fusion Applications
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2017 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T170, article id 010201Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Institute of Physics (IOP), 2017
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-220608 (URN)10.1088/1402-4896/aa9958 (DOI)000417694700001 ()
Note

QC 20180115

Available from: 2018-01-15 Created: 2018-01-15 Last updated: 2018-02-21Bibliographically approved
Masuzakil, S., Tokitanii, M., Otsuka, T., Oya, Y., Hatan, Y., Miyamoto, M., . . . Rubel, M. (2017). Analyses of microstructure, composition and retention of hydrogen isotopes in divertor tiles of JET with the ITER-like wall. Paper presented at 16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY. Physica Scripta, T170, Article ID 014031.
Open this publication in new window or tab >>Analyses of microstructure, composition and retention of hydrogen isotopes in divertor tiles of JET with the ITER-like wall
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2017 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T170, article id 014031Article in journal (Refereed) Published
Abstract [en]

Results of the comprehensive surface analyses of divertor tiles and dusts retrieved from JET after the first ITER-like wall campaign (2011-2012) are presented. The samples cored from the divertor tiles were analyzed. Numerous nano-size bubble-like structures were observed in the deposition layer on the apron of the inner divertor tile, and a beryllium dust with the same structures were found in the matter collected from the inner divertor after the campaign. This suggests that the nano-size bubble-like structures can make the deposition layer to become brittle and may lead to cracking followed by dust generation. X-ray photoelectron spectroscopy analyses of chemical states of species in the deposition layers identified the formation of beryllium-tungsten intermetallic compounds on an inner vertical tile. Different tritium retention profiles along the divertor tiles were observed at the top surfaces and at deeper regions of the tiles by using the imaging plate technique.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2017
Keywords
JET, ITER-like wall, dust, XPS, divertor tiles, tritium retention, microstructure
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-217723 (URN)10.1088/1402-4896/aa8bcc (DOI)000414120500031 ()2-s2.0-85045301547 (Scopus ID)
Conference
16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY
Note

QC 20171123

Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2017-11-23Bibliographically approved
Catarino, N., Barradas, N. P., Corregidor, V., Widdowson, A., Baron-Wiechec, A., Coad, J. P., . . . Alves, E. (2017). Assessment of erosion, deposition and fuel retention in the JET-ILW divertor from ion beam analysis data. NUCLEAR MATERIALS AND ENERGY, 12, 559-563
Open this publication in new window or tab >>Assessment of erosion, deposition and fuel retention in the JET-ILW divertor from ion beam analysis data
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2017 (English)In: NUCLEAR MATERIALS AND ENERGY, ISSN 2352-1791, Vol. 12, p. 559-563Article in journal (Refereed) Published
Abstract [en]

Post-mortem analyses of individual components provide relevant information on plasma-surface interactions like tungsten erosion, beryllium deposition and plasma fuel retention with divertor tiles via implantation or co-deposition. Ion Beam techniques are ideal tools for such purposes and have been extensively used for post-mortem analyses of selected tiles from JET following each campaign. In this contribution results from tiles removed from the JET ITER-Like Wall (JET-ILW) divertor following the 2013-2014 campaign are presented. The results summarize erosion, deposition and fuel retention along the poloidal cross section of the divertor surface and provide data for comparison with the first JET-ILW campaign, showing a similar pattern of material migration with the exception of Tile 6 where the strike point time on the tile was similar to 4 times longer in 2013-2014 than in 2011-2012, which is likely to account for more material migration to this region. The W deposition on top of the Mo marker coating of Tile 4 shows that the enrichment takes place at the strike point location.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-220641 (URN)10.1016/j.nme.2016.10.027 (DOI)000417293300088 ()2-s2.0-85006922988 (Scopus ID)
Note

QC 20180111

Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-03-12Bibliographically approved
Tsavalas, P., Lagoyannis, A., Mergia, K., Rubel, M., Triantou, K., Harissopulos, S., . . . Petersson, P. (2017). Be ITER-like wall at the JET tokamak under plasma. Paper presented at 16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY. Physica Scripta, T170, Article ID 014049.
Open this publication in new window or tab >>Be ITER-like wall at the JET tokamak under plasma
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2017 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T170, article id 014049Article in journal (Refereed) Published
Abstract [en]

The JET tokamak is operated with beryllium and tungsten plasma-facing components to prepare for the exploitation of ITER. To determine beryllium erosion and migration in JET a set of markers were installed. Specimens from different beryllium marker tiles of the main wall of the ITER-like wall (ILW) JET tokamak from the first and the second D-D campaign were analyzed with nuclear reaction analysis, x-ray fluorescence spectroscopy, scanning electron microscopy and x-ray diffraction (XRD). Emphasis was on the determination of carbon plasma impurities deposited on beryllium surfaces. The C-12(d, p(0))C-13 reaction was used to quantify carbon deposition and to determine depth profiles. Carbon quantities on the surface of the Be tiles are low, varying from (0.35 +/- 0.07) x 10(17) to (11.8 +/- 0.6) x 10(17) at cm(-2) in the deposition depth from 0.4 to 6.7 mu m, respectively. In the 0.4-0.5 mm wide grooves of castellation sides the carbon content is found up to (14.3 +/- 2.5) x 10(17) at cm(-2) while it is higher (up to (38 +/- 4) x 10(17) at cm(-2)) in wider gaps (0.8 mm) separating tile segments. Oxygen (O), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni) and tungsten (W) were detected in all samples exposed to plasma and the reference one but at lower quantities at the latter. In the central part of the Inner Wall Guard Limiter from the first ILW campaign and in the Outer Poloidal Limiter from the second ILW campaign the Ni interlayer has been completely eroded. XRD shows the formation of BeNi in most specimens.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2017
Keywords
beryllium, JET tokamak, ITER like wall, plasma, nuclear reaction analysis, erosiond-eposition
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-217725 (URN)10.1088/1402-4896/aa8ff4 (DOI)000414120500049 ()
Conference
16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY
Note

QC 20171123

Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2017-11-23Bibliographically approved
Louche, F., Wauters, T., Ragona, R., Moeller, S., Durodie, F., Litnovsky, A., . . . Van Schoor, M. (2017). Design of an ICRF system for plasma-wall interactions and RF plasma production studies on TOMAS. Paper presented at 29th Symposium on Fusion Technology (SOFT), SEP 05-09, 2016, Prague, CZECH REPUBLIC. Fusion engineering and design, 123, 317-320
Open this publication in new window or tab >>Design of an ICRF system for plasma-wall interactions and RF plasma production studies on TOMAS
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2017 (English)In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 317-320Article in journal (Refereed) Published
Abstract [en]

Ion cyclotron wall conditioning (ICWC) is being developed for ITER and W7-X as a baseline conditioning technique in which the ion cyclotron heating and current drive system will be employed to produce and sustain the currentless conditioning plasma. The TOMAS project (TOroidal MAgnetized System, operated at the FZ-juelich, Germany) proposes to explore several key aspects of ICWC. For this purpose we have designed an ICRF system made of a single strap antenna within a metallic box, connected to a feeding port and a pre-matching system. We discuss the design work of the antenna system with the help of the commercial electromagnetic software CST Microwave Studio (R). The simulation results for a given geometry provide input impedance matrices for the two-port system. These matrices are afterwards inserted into various circuit models to assess the accessibility of the required frequency range. The sensitivity of the matching system to uncertainties on plasma loading and capacitance values is notably addressed. With a choice of three variable capacitors we show that the system can cope with such uncertainties. We also demonstrate that the system can cope as well with the high reflected power levels during the short breakdown phase of the RF discharge, but at the cost of a significantly reduced coupled power.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2017
Keywords
ICWC, Antennas, Capacitors, TOMAS, Matching, Simulations
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-221890 (URN)10.1016/j.fusengdes.2017.04.123 (DOI)000418992000063 ()
Conference
29th Symposium on Fusion Technology (SOFT), SEP 05-09, 2016, Prague, CZECH REPUBLIC
Note

QC 20180130

Available from: 2018-01-30 Created: 2018-01-30 Last updated: 2018-01-30Bibliographically approved
Vizvary, Z., Bourdel, B., Garcia Carrasco, A., Lam, N., Leipold, F., Pitts, R. A., . . . Widdowson, A. (2017). Engineering design and analysis of an ITER-like first mirror test assembly on JET. Paper presented at 29th Symposium on Fusion Technology (SOFT), SEP 05-09, 2016, Prague, CZECH REPUBLIC. Fusion engineering and design, 123, 1054-1057
Open this publication in new window or tab >>Engineering design and analysis of an ITER-like first mirror test assembly on JET
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2017 (English)In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 123, p. 1054-1057Article in journal (Refereed) Published
Abstract [en]

The ITER first mirrors are the components of optical diagnostic systems closest to the plasma. Deposition may build up on the surfaces of the mirror affecting their ability to fulfil their function. However, physics modelling of this layer growth is fraught with uncertainty. A new experiment is underway on JET, under contract to ITER, with primary objective to test if, under realistic plasma and wall material conditions and with ITER-like first mirror aperture geometry, deposits do grow on first mirrors. This paper describes the engineering design and analysis of this mirror test assembly. The assembly was installed in the 2014-15 shutdown and will be removed in the 2016-17 shutdown.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2017
Keywords
ITER-like first mirror, JET, Additive manufacturing, Remote handling, Disruption loads
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-221891 (URN)10.1016/j.fusengdes.2016.12.016 (DOI)000418992000221 ()
Conference
29th Symposium on Fusion Technology (SOFT), SEP 05-09, 2016, Prague, CZECH REPUBLIC
Note

QC 20180131

Available from: 2018-01-31 Created: 2018-01-31 Last updated: 2018-01-31Bibliographically approved
Fortuna-Zalesna, E., Grzonka, J., Moon, S., Rubel, M., Petersson, P. & Widdowson, A. (2017). Fine metal dust particles on the wall probes from JET-ILW. Paper presented at 16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY. Physica Scripta, T170, Article ID 014038.
Open this publication in new window or tab >>Fine metal dust particles on the wall probes from JET-ILW
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2017 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T170, article id 014038Article in journal (Refereed) Published
Abstract [en]

Collection and ex situ studies of dust generated in controlled fusion devices during plasma operation are regularly carried out after experimental campaigns. Herewith results of the dust survey performed in JET after the second phase of operation with the metal ITER-like wall (2013-2014) are presented. For the first-time-ever particles deposited on silicon plates acting as dust collectors installed in the inner and outer divertor have been examined. The emphasis is on analysing metal particles (Be and W) with the aim to determine their composition, size and surface topography. The most important is the identification of beryllium dust in the form of droplets (both splashes and spherical particles), flakes of co-deposits and small fragments of Be tiles. Tungsten and nickel rich (from Inconel) particles are also identified. Nitrogen from plasma edge cooling has been detected in all types of particles. They are categorized and the origin of various constituents is discussed.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2017
Keywords
plasma, dust, JET tokamak, ITER-like wall, beryllium, tungsten
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-217721 (URN)10.1088/1402-4896/aa8ddf (DOI)000414120500038 ()
Conference
16th International Conference on Plasma-Facing Materials and Components for Fusion Applications, MAY 16-19, 2017, GERMANY
Note

QC 20171123

Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2017-11-23Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9901-6296

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