Alpha particle transient response of a polycrystalline diamond detector Original Research Article

We report the transient response of room temperature pulses generated from alpha particles from a chemical vapor deposition (CVD) polycrystalline diamond detector. For transient signals dominated by electron transport only prompt pulse shapes were observed with an average rise time of 160 ns limited by the preamplifier rise time. For transient signals dominated by hole transport significant slow components were observed in the majority of pulses due to thermal emission of charge from shallow hole traps. These slow pulses were observed from the device when in its as-grown state, without any previous ‘priming’. Two separate slow components were identified from the hole pulses, with average rise times of 600 ns and 1–10 μs, respectively. These data suggest that room temperature electron transport in polycrystalline CVD diamond is prompt, with no evidence for thermal de-trapping. In contrast hole transport in our sample at room temperature contains a significant delayed component due to thermal emission of holes from at least two bands of shallow defects.