Temperature influence on deuterium retention for Be–W mixed thin films prepared by Thermionic Vacuum Arc method exposed to PISCES B plasma

Abstract

Beryllium–tungsten thin films with well controlled elemental composition were prepared using Thermionic Vacuum Arc (TVA) technique and subsequently exposed to steady state, high ion flux (5.5−9.8×1022ionsm−2s−1) deuterium (D) plasma in the PISCES-B facility to consistent fluences of 2.3×1026m−2. Six types of layers were studied, ranging from pure Be, composite Be–W, having the atomic ratios of 9:1; 7:3; 1:1; 3:7; to pure W with a total deposited layer thickness of 2μm. The sample exposure temperatures, namely 300K, 473K, 573K and 773K, respectively, were measured in situ with a thermocouple placed on the back of the sample. Morphological and structural examinations were undertaken before and after plasma exposure. Results show an influence of temperature on the subsequent morphology of the surface. Thermal Desorption Spectrometry (TDS) spectra showed a change in the D release behavior for different Be–W ratio for a certain exposure temperature.