Thin Film Cadmium Telluride Charged Particle Sensors for Large Area Neutron Detectors

Thin film semiconductor neutron detectors are an attractive candidate to replace ³He neutron detectors, due to the possibility of low cost manufacturing and the potential for large areas. Polycrystalline CdTe is found to be an excellent material for thin film charged particle detectors−an integral component of a thin film neutron detector. The devices presented here are characterized in terms of their response to alpha and gamma radiation. Individual alpha particles are detected with an intrinsic efficiency of >80%, while the devices are largely insensitive to gamma rays, which is desirable so that the detector does not give false positive counts from gamma rays. The capacitance-voltage behavior of the devices is studied and correlated to the response due to alpha radiation. When coupled with a boron-based neutron converting material, the CdTe detectors are capable of detecting thermal neutrons.