Channeling radiation from LiH and LiD

Abstract

We have obtained channeling-radiation spectra for both electrons and positrons incident along the major planes of LiH and LiD crystals. Analysis of the data yields two significant results: (1) the thermal-vibration amplitude of LiD is smaller than that of LiH, as one would expect for this isotopic effect, but in contradiction with tabulated values; and (2) a tunneling transition was observed for 54-MeV electron channeling along the (111) planes of both LiH and LiD.