Beta environmental fine structure characterization of defects

The fine structure of beta emission (BEFS) due to the interference with the scattered waves from neighboring atoms, analogous to EXAFS, is known to pr oduce oscillations in the Kurie plot. Here we suggest the use of BEFS for c haracterizing the lattice environment of beta-emitting defects located at a distance from the crystal surface not exceeding the mean free path of beta -electrons. Examples of defective structures in semiconductors whose atomic arrangement could be conveniently studied with BEFS are tritium-passivated dangling bonds, beta-radioactive ions implanted in the crystal lattice or segregated at extended defects such as dislocations, grain boundaries or ra diation damage. Also C-14-doped diamond-like materials and other exotic car bon forms, as well as the atomic environment of ions in metal alloys could be good candidate for BEFS. In this work we have calculated the fractional BEFS modulation for Re-187 in its ordinary hcp crystal lattice for which ex perimental data by Cosulich et al. are available. The good correspondence b etween theory and experiment permits to conclude that BEFS experiments at l ow temperature are accessible to the present bolometric detection technique s and can provide an expedient method, as compared to EXAFS, for an accurat e structural assessment of extended defects in solids. (C) 1999 Elsevier Sc ience B.V. All rights reserved.