Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor

H. Bergsker, I. Bykov, Y. Zhou, P. Petersson, G. Possnert, J. Likonen, J. Pettersson, S. Koivuranta, A.M. Widdowson

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (µ-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of µ-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (3He, p) µ-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 µm, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 µm. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at% in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.
Original languageEnglish
Article number014061
Number of pages8
JournalPhysica Scripta
Volume2016
Issue numberT167
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Fingerprint

deuterium
tungsten
secondary ion mass spectrometry
surface roughness effects
scanning electron microscopy
tiles
Tile
Surface Roughness
Profiling
Trapping
nuclear reactions
Coating
flat surfaces
Plasma
trapping
Sufficient
coatings
profiles
Energy
Range of data

Keywords

  • beryllium
  • deuterium
  • ion beam analysis
  • materials migration

Cite this

Bergsker, H., Bykov, I., Zhou, Y., Petersson, P., Possnert, G., Likonen, J., ... Widdowson, A. M. (2016). Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor. Physica Scripta, 2016(T167), [014061]. https://doi.org/10.1088/0031-8949/T167/1/014061
Bergsker, H. ; Bykov, I. ; Zhou, Y. ; Petersson, P. ; Possnert, G. ; Likonen, J. ; Pettersson, J. ; Koivuranta, S. ; Widdowson, A.M. / Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor. In: Physica Scripta. 2016 ; Vol. 2016, No. T167.
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title = "Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor",
abstract = "Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (µ-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of µ-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (3He, p) µ-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 µm, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 µm. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at{\%} in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.",
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Bergsker, H, Bykov, I, Zhou, Y, Petersson, P, Possnert, G, Likonen, J, Pettersson, J, Koivuranta, S & Widdowson, AM 2016, 'Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor', Physica Scripta, vol. 2016, no. T167, 014061. https://doi.org/10.1088/0031-8949/T167/1/014061

Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor. / Bergsker, H.; Bykov, I.; Zhou, Y.; Petersson, P.; Possnert, G.; Likonen, J.; Pettersson, J.; Koivuranta, S.; Widdowson, A.M.

In: Physica Scripta, Vol. 2016, No. T167, 014061, 2016.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Deep deuterium retention and Be/W mixing at tungsten coated surfaces in the JET divertor

AU - Bergsker, H.

AU - Bykov, I.

AU - Zhou, Y.

AU - Petersson, P.

AU - Possnert, G.

AU - Likonen, J.

AU - Pettersson, J.

AU - Koivuranta, S.

AU - Widdowson, A.M.

PY - 2016

Y1 - 2016

N2 - Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (µ-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of µ-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (3He, p) µ-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 µm, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 µm. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at% in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.

AB - Surface samples from a full poloidal set of divertor tiles exposed in JET through operations 2010-2012 with ITER-like wall have been investigated using SEM, SIMS, ICP-AES analysis and micro beam nuclear reaction analysis (µ-NRA). Deposition of Be and retention of D is microscopically inhomogeneous. With careful overlaying of µ-NRA elemental maps with SEM images, it is possible to separate surface roughness effects from depth profiles at microscopically flat surface regions, without pits. With (3He, p) µ-NRA at 3-5 MeV beam energy the accessible depth for D analysis in W is about 9 µm, sufficient to access the W/Mo and Mo/W interfaces in the coatings and beyond, while for Be in W it is about 6 µm. In these conditions, at all plasma wetted surfaces, D was found throughout the whole accessible depth at concentrations in the range 0.2-0.7 at% in W. Deuterium was found to be preferentially trapped at the W/Mo and Mo/W interfaces. Comparison is made with SIMS profiling, which also shows significant D trapping at the W/Mo interface. Mixing of Be and W occurs mainly in deposited layers.

KW - beryllium

KW - deuterium

KW - ion beam analysis

KW - materials migration

U2 - 10.1088/0031-8949/T167/1/014061

DO - 10.1088/0031-8949/T167/1/014061

M3 - Article

VL - 2016

JO - Physica Scripta

JF - Physica Scripta

SN - 0031-8949

IS - T167

M1 - 014061

ER -