AMORPHOUS-SILICON POSITION-SENSITIVE NEUTRON DETECTOR

Abstract

In this work, we present an investigation of the possibility of using an a-Si:H diode, coated with an appropriate converter, as a position sensitive neutron detector. Our Monte Carlo simulation predicts that using a Gd film, approximately 2mum thick, coated on a sufficiently thick amorphous silicon n-i-p diode, we can achieve a neutron detection efficiency of 25 percent. The experimental results presented give an average signal size of about 12000 e- per neutron interaction, which is well above the noise and is in good agreement with the expected values. We can also fabricate pixel detectors with element size as small as 300 mum and still register a count rate of 2200 events/sec in a typical neutron flux situation of about 10(7) n/cm2sec. The fact that these detectors are not sensitive to gamma rays, and show excellent radiation hardness, make them good candidates for applications such as neutron imaging, neutron crystallography and neutron scattering.