Study of Doppler-broadened annihilation radiation in metals with a Ge(Li) detector

Abstract

We have investigated the Doppler-broadened annihilation radiation spectra arising from positron-electron annihilation in twelve metals. A plot of αX² vs. E_F for these metals, when grouped according to the periodic table, results in straight lines, (α is the effective-electron-mass ratio m^∗/m₀, X is a measure of the observed broadening, and E_F is the Fermi energy). This feature is consistent with a simple theoretical model. In addition, it suggests a possible method for determining the electron effective mass in other metals. We have utilized this to estimate the effective-mass ratio for B as 2.8.