Semiconductor particle detectors are ideal for alpha spectroscopy due to their compact size, low noise, and high resolution.
This paper describes the construction and testing of an automatic sample changer for use with such a detector. The changer
was constructed from locally available services and materials. It holds up to 24 samples of alpha emitting material deposited
on 22 mm stainless steel counting planchets. The vacuum chamber can be evacuated to less than 10 μm mercury in 10 to 15 minutes.
Once the chamber has been evacuated and detector bias has been applied, any sample in the chamber may be selected for analysis,
either automatically or manually. Continuous automatic analysis of up to 24 samples is possible. Variation in efficiency from
position to position was found to be 3.25% at the detector-sample spacing of 4.8 mm, and 2.31% at 27 mm. Shielding between
the adjacent samples not under analysis and the detector was acceptable.