Study of the Doppler broadening of positron annihilation radiation in silicon

We report the measurement of Doppler broadening annihilation radiation in silicon, using 22Na as a positron source, and two Ge detectors arrangement. The two-dimensional coincidence energy spectrum was fitted using a model function. The model function included at rest positron annihilation with valence band, 2p, 2s, and 1s electrons. In-flight positron annihilation was also fitted. The detectors response functions included backscattering, and a combination of Compton effects, pileup, ballistic deficit, and pulse shaping problems. The obtained results agree well with the literature.