Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma

M. Thompson; A. Deslandes; T. W. Morgan; R. G. Elliman; G. De Temmerman; P. Kluth; D. Riley; C. S. Corr

doi:10.1088/0029-5515/56/10/104002

Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma

M. Thompson, A. Deslandes, T. W. Morgan, R. G. Elliman, G. De Temmerman, P. Kluth, D. Riley, C. S. Corr

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

Helium retention is measured in tungsten samples exposed to mixed H/He plasma in the Magnum-PSI linear plasma device. It is observed that there is very little He retention below helium ion impact energies of eV, indicating the existence of a potential barrier which must be overcome for implantation to occur. The helium retention in samples exposed to plasma at temperatures >1000 K is strongly correlated with nano-bubble formation measured using grazing incidence small-angle x-ray scattering. The diameters of nano-bubbles were not found to increase with increasing helium concentration, indicating that additional helium must be accommodated by increasing the bubble concentration or an increase in bubble pressure. For some samples pre-irradiation with heavy ions of 2.0 MeV energy is investigated to simulate the effects of neutron damage. It is observed that nano-bubble sizes are comparable between samples pre-irradiated with heavy-ions, and those without heavy-ion pre-irradiation.

Original language	English
Article number	104002
Journal	Nuclear Fusion
Volume	56
Issue number	10
DOIs	https://doi.org/10.1088/0029-5515/56/10/104002
Publication status	Published - 16 Aug 2016

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title = "Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma",

abstract = "Helium retention is measured in tungsten samples exposed to mixed H/He plasma in the Magnum-PSI linear plasma device. It is observed that there is very little He retention below helium ion impact energies of eV, indicating the existence of a potential barrier which must be overcome for implantation to occur. The helium retention in samples exposed to plasma at temperatures >1000 K is strongly correlated with nano-bubble formation measured using grazing incidence small-angle x-ray scattering. The diameters of nano-bubbles were not found to increase with increasing helium concentration, indicating that additional helium must be accommodated by increasing the bubble concentration or an increase in bubble pressure. For some samples pre-irradiation with heavy ions of 2.0 MeV energy is investigated to simulate the effects of neutron damage. It is observed that nano-bubble sizes are comparable between samples pre-irradiated with heavy-ions, and those without heavy-ion pre-irradiation.",

keywords = "GISAXS, helium retention, magnum-PSI, nano-bubble, tungsten",

author = "M. Thompson and A. Deslandes and Morgan, {T. W.} and Elliman, {R. G.} and {De Temmerman}, G. and P. Kluth and D. Riley and Corr, {C. S.}",

note = "Publisher Copyright: {\textcopyright} 2016 EURATOM.",

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doi = "10.1088/0029-5515/56/10/104002",

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T1 - Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma

AU - Thompson, M.

AU - Deslandes, A.

AU - Morgan, T. W.

AU - Elliman, R. G.

AU - De Temmerman, G.

AU - Kluth, P.

AU - Riley, D.

AU - Corr, C. S.

PY - 2016/8/16

Y1 - 2016/8/16

N2 - Helium retention is measured in tungsten samples exposed to mixed H/He plasma in the Magnum-PSI linear plasma device. It is observed that there is very little He retention below helium ion impact energies of eV, indicating the existence of a potential barrier which must be overcome for implantation to occur. The helium retention in samples exposed to plasma at temperatures >1000 K is strongly correlated with nano-bubble formation measured using grazing incidence small-angle x-ray scattering. The diameters of nano-bubbles were not found to increase with increasing helium concentration, indicating that additional helium must be accommodated by increasing the bubble concentration or an increase in bubble pressure. For some samples pre-irradiation with heavy ions of 2.0 MeV energy is investigated to simulate the effects of neutron damage. It is observed that nano-bubble sizes are comparable between samples pre-irradiated with heavy-ions, and those without heavy-ion pre-irradiation.

AB - Helium retention is measured in tungsten samples exposed to mixed H/He plasma in the Magnum-PSI linear plasma device. It is observed that there is very little He retention below helium ion impact energies of eV, indicating the existence of a potential barrier which must be overcome for implantation to occur. The helium retention in samples exposed to plasma at temperatures >1000 K is strongly correlated with nano-bubble formation measured using grazing incidence small-angle x-ray scattering. The diameters of nano-bubbles were not found to increase with increasing helium concentration, indicating that additional helium must be accommodated by increasing the bubble concentration or an increase in bubble pressure. For some samples pre-irradiation with heavy ions of 2.0 MeV energy is investigated to simulate the effects of neutron damage. It is observed that nano-bubble sizes are comparable between samples pre-irradiated with heavy-ions, and those without heavy-ion pre-irradiation.

KW - GISAXS

KW - helium retention

KW - magnum-PSI

KW - nano-bubble

KW - tungsten

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U2 - 10.1088/0029-5515/56/10/104002

DO - 10.1088/0029-5515/56/10/104002

M3 - Article

SN - 0029-5515

VL - 56

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 10

M1 - 104002

ER -

Observation of a helium ion energy threshold for retention in tungsten exposed to hydrogen/helium mixture plasma

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