Coincidence Doppler Broadening of Positron Annihilation Radiation in Fe

16th International Conference on Positron Annihilation

Do Nascimento, E.^1 ; Vanin, V.R.^1 ; Maidana, N.L.^1 ; Helene, O.^1

Institute de Física, Universidade de São Paulo, São Paulo, SP, Brazil^1

关键词: Annihilation radiations;    Ballistic deficit;    Coincidence doppler broadening;    Model functions;    Positron annihilation radiation;    Positron sources;    Response functions;    Theoretical values;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012024/pdf
DOI  :  10.1088/1742-6596/443/1/012024

来源: IOP

【 摘 要 】

We measured the Doppler broadening annihilation radiation spectrum in Fe, using22NaCl as a positron source, and two Ge detectors in coincidence arrangement. The two-dimensional coincidence energy spectrum was fitted using a model function that included positron annihilation with the conduction band and 3d electrons, 3s and 3p electrons, and in-flight positron annihilation. Detectors response functions included backscattering and a combination of Compton and pulse pileup, ballistic deficit and shaping effects. The core electrons annihilation intensity was measured as 16.4(3) %, with almost all the remainder assigned to the less bound electrons. The obtained results are in agreement with published theoretical values.