Deuterium retention in tungsten exposed to low-energy pure and helium-seeded deuterium plasmas

• Published in: Journal of applied physics 2011-01, Vol.109 (1)
• Main Authors: Ogorodnikova, O. V., Schwarz-Selinger, T., Sugiyama, K., Alimov, V. Kh
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CARBON; CHARGED PARTICLES; CHEMICAL ANALYSIS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COATINGS; CRYSTALS; CYCLOTRON RESONANCE; DENSITY; DESORPTION; DEUTERIUM; ELECTRON CYCLOTRON-RESONANCE; ELEMENTS; FLUIDS; GASES; HELIUM; HELIUM IONS; HYDROGEN ISOTOPES; ION IMPLANTATION; IONS; ISOTOPES; LIGHT NUCLEI; METALS; NONDESTRUCTIVE ANALYSIS; NONMETALS; NUCLEAR REACTION ANALYSIS; NUCLEI; ODD-ODD NUCLEI; PHYSICAL PROPERTIES; PLASMA; POLYCRYSTALS; RARE GASES; REFRACTORY METALS; RESONANCE; RETENTION; SORPTION; SPECTROSCOPY; STABLE ISOTOPES; SUBSTRATES; TRANSITION ELEMENTS; TRAPS; TUNGSTEN; WALL EFFECTS
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3505754

Influence of helium (He) on the deuterium (D) retention in tungsten (W) under simultaneous He-D plasma exposure was investigated. Bulk polycrystalline tungsten and two W coatings on carbon substrate, namely, plasma-sprayed tungsten and combined magnetron-sputtered and ion implanted tungsten (CMSII-W) were exposed to pure and He-seeded D plasmas generated by electron-cyclotron-resonance plasma source. The D retention in each sample was subsequently analyzed by various methods such as nuclear reaction analysis for the D depth profiling up to 6 μm and thermal desorption spectroscopy for the determination of total amount of D retention. It is shown that seeding of helium into D plasma with helium ion flux fraction of 10% reduces the deuterium retention for all tungsten grades but more significant reduction was observed for polycrystalline W and less significant effect was found for W coatings. From the thermal desorption spectroscopy measurements, we conclude that the presence of He modifies the density of existing traps for D but does not modify the nature of traps. Maximum effect of a reduction in the deuterium retention due to helium seeding was observed at around 500 K for bulk polycrystalline W. Mechanisms of deuterium retention and He effect in different W materials are discussed.