title: Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector.
abstract: The response of a semiconductor alpha detector to fast (>1 MeV) neutrons was investigated by using measurements and simulations. A polyethylene converter was placed in front of the detector to register recoil protons generated by elastic collisions between neutrons and hydrogen nuclei of the converter. The developed prototype equipment was tested with shielded radiation sources. The low background of the detector and insensitivity to high-energy gamma rays above 1 MeV are advantages when the detection of neutron-emitting nuclear materials is of importance. In the case of a (252)Cf neutron spectrum, the intrinsic efficiency of fast neutron detection was determined to be 2.5×10(-4), whereas three-fold greater efficiency was obtained for a (241)AmBe neutron spectrum.
authors.affiliation: STUK - Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland. Electronic address: roy.pollanen@stuk.fi.
authors.forename: R
authors.initials: R
authors.lastname: Pöllänen
authors.affiliation: STUK - Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Siiskonen
keywords: Alpha spectrometry; Monte Carlo simulation; Neutron; Silicon detector