A Linear Mode Avalanche Photodiode for Ion Detection in the Energy Range 5–250 keV

We investigated the response linearity and the energy resolution of a silicon based reach-through avalanche photodiode (APD) for low energy ions ranging from 5 keV to 250 keV. We found that space charge affects the APD gain, and that this could be compensated by applying a simple correction formula to the measured pulse height distributions. The comparison between former theoretical or experimental studies and our results showed that there was no evidence of additional performance degradation within the tested energy range in terms of the linearity and the energy resolution compared to conventional non-avalanching silicon detectors. Thanks to the low noise level (equivalent to 0.9 keV in silicon) at the room temperature even for a large detection area (15 mm²), APDs would be potentially used for detection of low-energy ions in various environments such as space plasma physics, particle physics, and many industrial applications.