Cross section for the production of electron-positron pairs by 1.064-MeV photons on germanium

Abstract

The relative pair-production rates by 1.064- and 1.770-MeV photons on Ge were measured in a double-escape-peak pair spectrometer consisting of a 2.44-cm diameter by 1-cm-thick intrinsic, planar Ge detector inside of a split NaI(Tl) annulus. Guided by previous experiments, the theoretical cross section $\ensuremath{\sigma}(1.770)$ was assumed to be correct and the value $\ensuremath{\sigma}(1.064)=0.131\ifmmode\pm\else\textpm\fi{}0.012$ mb/atom was deduced from the data. This is in excellent agreement with recent direct numerical screened calculations of Tseng and Pratt.