The performance of charged particle counters associating thin diamond or am
orphous silicon (a-Si) detectors to Castor VLSI analog-digital circuits for
the fabrication of large area detectors are reported. The 20 mum thick sem
iconductor detectors were synthesised using chemical vapour deposition (CVD
) technique. Detectors of 2.5 x 2.5 cm(2) area were segmented in 32 sub-are
as of 13 mm(2) in order to limit the electronic noise per reading channel.
The 32 channel circuit was used to record the counting rate and the total n
umber of counts on each segment. Such detection systems were tested under a
lpha particles (Am-241) as well as under low energy beta particles (C-14).
The results show that large area detection systems can readily be fabricate
d at low cost by the association of an application specific readout chip (A
SIC) with chemically vapour deposited semiconductor detectors.