Fast neutron detector using PIN-type silicon photodiode

A new fast neutron detector has been developed using a PIN-type windowless photodiode with a polyethylene radiator of 45 μm thickness and a low noise charge sensitive preamplifier for the photodiode. The detection efficiency was 7.8 × 10−5 for fast neutrons and the detector was sensitive to neutrons with an energy higher than 1.2 MeV. Additionally the thickness of the depletion layer in the photodiode can be estimated using the saturated range of recoil proton pulses. ge sensitive preamplifier with lower noise is described for the photodiode radiation detection systems. The input stage of this preamplifier consists of four FETs. The equivalent noise charge was obtained as 1.1 × 10−16 C (FWHM) when connected to the photodiode. be concluded that this new system can be successfully used as a simple fast neutron detector.