Neutron Detection with Large Plastic Scintillators for RPM Applications

Homeland security requests the use Radiation Portal Monitor (RPM) to detect and differentiate gamma and neutron radiation. Gamma detection is required for illicit transportation of radioactive matter detection. Neutron detection is important to control nonproliferation of enriched material. Manufacturers worldwide propose sensors based on He-3 which give the actual state of art in term of neutron detection. The price fluctuations due to the announcement of the shortage of He-3 forces manufacturers to find viable alternative. From 10 years sensors providers have the challenge to replace previous He-3 detectors that are known to be the most commonly deployed neutron sensor. As He-3 detectors can only detect neutron, they must be completed with gamma detector. The proposed approach is based on pulse time correlation between adjacent sensors from signal collected by EJ200 plastic scintillators to detect gamma and neutron. Results obtained during FP7 Scintilla project test campaigns show the system relevance for replacement of today's He-3 detectors.