Polyurethane-Based Scintillators for Neutron and Gamma Radiation Detection in Medical and Industrial Applications

Organic scintillators using a solid polyurethane (PU) matrix have been introduced to combine the robustness of a construction material with scintillating properties that allow gamma rays and fast neutrons to be detected efficiently and at low cost. This work compares two corresponding materials, the older M600 and the more recent M700, with EJ-276D and EJ-200 representing common plastic scintillators with and without pulse-shape discrimination (PSD) capabilities, respectively. Characterization measurements were performed with small samples of 26 mm diameter and 10 mm height, which were coupled to a photomultiplier tube (PMT) and simultaneously exposed to 252Cf fission neutrons and 137Cs gamma rays. M700 turned out to provide the best PSD performance and about the same light yield as EJ-276D, while its light pulses exhibit a shorter pulse decay. An accelerated ageing process applied in between two test campaigns was too short to trigger distinct performance degradation in any of the materials, though optical degradation was visible in EJ-276D and in EJ-200 but not in the PU-based materials. Nevertheless, the extremely robust polyurethane matrix promises advantages in medical and industrial applications where resilience and long-term stability are of crucial importance.