Effect of carbon on accumulation of deuterium in beryllium irradiated with stationary plasma

Abstract

Beryllium targets placed in the PLAST beam-plasma discharge facility were irradiated with a flux of stationary deuterium (D) plasma with a deuterium ion energy of 200 eV and plasma flux density of 3 × 10²⁰ m⁻² s⁻¹ at temperatures of 370 and 670 K. The irradiation doses varied from 5 × 10²¹ to 10²⁴ m⁻². To heat the target and to ionize impurities near its surface the target was irradiated with an electron beam. The deuterium concentration at the target center exceeds its concentration at the periphery by a factor of more than two under all irradiation conditions. The target center was enriched with carbon up to 16–24 at %, as compared to 4–6 at % at the target periphery. The [D]: [Be] atomic concentration ratios at the target center were equal to 0.054 and 0.036 against 0.024 and 0.016 at the periphery at temperatures of 370 and 670 K, respectively. It has been found that these ratios depend on the concentration of carbon atoms which trapped deuterium atoms.