Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films

Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare 3 He gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for γ-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with 10 B thin film prototypes and a 3 He detector. It is demonstrated that equal γ-ray rejection to that of 3 He tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid 10 B layers, such as 6 Li layers and 10 BF 3 gas.