F-center formation by Br K-hole Auger decay in KBr.

Abstract

Spectral dependence of the {ital F}-center formation efficiency has been measured for KBr single crystals at liquid-helium and nitrogen temperatures in the vicinity of the {ital K} edge of bromine at 13.47 keV. The {ital F}-center formation efficiency was evaluated by the optical absorption measurement under irradiation with monochromatized synchrotron x rays. The efficiency was normalized to the deposited x-ray energy estimated by a sensitive photocalorimetric measurement. It has been found that the {ital F}-center formation efficiency shows an {approximately}24{percent} stepwise increase above the core threshold at liquid-helium temperature. This result suggests that the multiple ionization mechanism, following the core-hole Auger cascade, might participate actively in the {ital F}-center formation process. {copyright} {ital 1996 The American Physical Society.}