Helium release and microstructural changes in Er(D,T)2-x3Hex films).

Gelles, D. S. (Pacific Northwest National Laboratory, Richland, WA) ; Browning, James Frederick ; Snow, Clark Sheldon ; Banks, James Clifford ; Mangan, Michael A. ; Rodriguez, Mark Andrew ; Brewer, Luke N. ; Kotula, Paul Gabriel

Sandia National Laboratories

关键词: Decay;    Tritium;    Thickness;    Helium I;    Diffraction;   

DOI  :  10.2172/945172
RP-ID  :  SAND2007-7983
RP-ID  :  AC04-94AL85000
RP-ID  :  945172

美国|英语

来源: UNT Digital Library

【 摘 要 】

Er(D,T){sub 2-x} {sup 3}He{sub x}, erbium di-tritide, films of thicknesses 500 nm, 400 nm, 300 nm, 200 nm, and 100 nm were grown and analyzed by Transmission Electron Microscopy, X-Ray Diffraction, and Ion Beam Analysis to determine variations in film microstructure as a function of film thickness and age, due to the time-dependent build-up of {sup 3}He in the film from the radioactive decay of tritium. Several interesting features were observed: One, the amount of helium released as a function of film thickness is relatively constant. This suggests that the helium is being released only from the near surface region and that the helium is not diffusing to the surface from the bulk of the film. Two, lenticular helium bubbles are observed as a result of the radioactive decay of tritium into {sup 3}He. These bubbles grow along the [111] crystallographic direction. Three, a helium bubble free zone, or 'denuded zone' is observed near the surface. The size of this region is independent of film thickness. Four, an analysis of secondary diffraction spots in the Transmission Electron Microscopy study indicate that small erbium oxide precipitates, 5-10 nm in size, exist throughout the film. Further, all of the films had large erbium oxide inclusions, in many cases these inclusions span the depth of the film.