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Updated: Apr 30, 2026
09:18
Laser-heating and Radiance Spectrometry for the Study of Nuclear Materials in Conditions Simulating a Nuclear Power Plant Accident
Published on: December 14, 2017
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Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector
1STUK - Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
Summary
This study details a semiconductor alpha detector modified with a polyethylene converter for fast neutron detection. It shows promise for identifying neutron-emitting materials due to its low background and gamma ray insensitivity.
Area of Science:
- Nuclear instrumentation
- Radiation detection physics
Background:
- Semiconductor alpha detectors are typically used for charged particle detection.
- Fast neutron detection presents challenges due to their neutral charge and high energy.
Purpose of the Study:
- To investigate the feasibility of using a semiconductor alpha detector for fast neutron detection (>1 MeV).
- To enhance neutron detection efficiency using a polyethylene converter.
Main Methods:
- Utilized a semiconductor alpha detector coupled with a polyethylene converter to detect recoil protons from elastic neutron scattering.
- Employed measurements and simulations to characterize detector response.
- Tested prototype equipment with shielded radiation sources.
Main Results:
- Achieved intrinsic efficiencies of 2.5×10⁻⁴ for a Californium-252 neutron spectrum.
- Observed a three-fold increase in efficiency for an Americium-241/Beryllium neutron spectrum.
- Demonstrated low background noise and insensitivity to gamma rays above 1 MeV.
Conclusions:
- The modified semiconductor alpha detector is effective for fast neutron detection.
- The detector's characteristics make it suitable for applications requiring the detection of neutron-emitting nuclear materials.
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