Large area thin film semiconductor detectors using multichannel counting Castor readout chip

The performance of charged particle counters associating thin diamond or amorphous silicon (a-Si) detectors to Castor VLSI analog-digital circuits for the fabrication of large area detectors are reported. The 20 μm thick semiconductor detectors were synthesised using the chemical vapour deposition (CVD) technique. Detectors of 2.5×2.5 cm² area were segmented in 32 sub-areas of 13 mm² in order to limit the electronic noise per reading channel. The 32 channel circuit was used to record the counting rate and the total number of counts on each segment. Such detection systems were tested under alpha particles (²⁴¹Am) as well as under low energy beta particles (¹⁴C). The results show that large area detection systems can readily be fabricated at low cost by the association of an application specific readout chip (ASIC) with chemically vapour deposited semiconductor detectors