Statistical analysis of the Doppler broadening coincidence spectrum of the electron-positron annihilation radiation in aluminum

摘要

We report a new, simplified and more efficient modeling on the statistical analysis of Doppler broadening coincidence data of the electron-positron annihilation radiation in aluminum, when compared with previous works. The Doppler broadening coincidence spectrum was fitted using a model function. The model function included positron annihilation at rest with the conduction band, 2p, 2s and Is electrons. In-flight positron annihilation was also fitted. The response functions of the detectors included backscattering, combinations of Compton effects, pileup, ballistic deficit and pulse shaping problems. The annihilation intensities obtained in this work were, for the conduction band 94.0(3)%, for the 2p electrons 5.7(3)%, for the 2s electrons 0.29(16)%, for the Is electrons 0.0126(13)%. The intensity of the in-flight positron annihilation was 0.064(3)%, and the three Fermi cutoff parameters obtained were 6.758(9), 10.013(11) and 15.532(10), in 10(-3)m(0)c units. The obtained results are compared with published data. (c) 2006 Elsevier B.V. All rights reserved.