Doppler broadening of positron annihilation radiation: fitting the coincidence spectrum

The profile of the annihilation radiation in aluminum using positrons from a 22 Na source was observed in a two-HPGe-detectors arrangement. The coincidence photon energy spectrum was fitted using a model function, accounting for both Doppler broadening and detector system response. Intensities of the thermalized positron annihilation with band, 2p, 2s, and 1s electrons, and in-flight positron annihilation were fitted. The binding energies of the 1s, 2s, and 2p electrons and the Fermi cutoff parameters of the band electrons were also fitted.