A spectrometer for the measurement of the Doppler broadening of the annihilation line with efficient reduction of background

Following Lynn and the suggestion made by MacKenzie we describe a Doppler broadening (DB) spectrometer with efficient reduction of the background (BG). The simple experimental set-up achieved a peak to the BG ratio for the annihilation line of the order 1000 : 1. In this work, attention is given to the problem of the BG correction under the annihilation line, which has not been described in the literature. Measurements of Doppler profile of the annihilation line in Ni, Cu and a single crystal of Si are presented as an illustration of the advantage of the applications of the suggested BG reduction and correction technique.