Thermal Desorption of D sub 2 and CD sub 4 From Bulk-Boronized Graphites

• Published in: Journal of nuclear materials Vol. 187; no. 2; pp. 191 - 196
• Main Authors: Alimov, V H, Schworer, R, Scherzer, B M U, Roth, J
• Format: Journal Article
• Language: English
• Published: 01.05.1992
• ISSN: 0022-3115

Thermal desorption spectra of D sub 2 and CD sub 4 from bulk-boronized graphites containing 3-38 wt.% boron (e.g. GB103, GB110, GB120, GB130, M-19a-II, and USB15) and from pure graphite (HPG99 and GB100) and stoichiometric B sub 4 C were measured. The samples were implanted with 3 keV D exp + sub 3 ions at temperatures between 130-700 deg C to fluences between 2.3 x 10 exp 16 D/cm exp 2 prior to the desorption. An enhancement of D sub 2 release is observed with increasing B content, while the CD sub 4 release decreases correspondingly. The desorption peak maximum of D sub 2 is shifted towards lower temperatures with increasing B concentrations. Apparently, it is the B in solid solution which mainly influences the trapping and release behaviour of deuterium. The formation of CD sub 4 is suggested to proceed via a precursor state. The formation of the complete CD sub 4 molecule takes place only close to the desorption temperature. The reduction of binding energy for deuterium has only a minor influence on ion-beam-induced detrapping.