Thermal neutron detection using thin PEN film doped with high cross section materials

Anotacija

Poly(ethylene 2,6-naphthalate) (PEN) is promising as a new plastic scintillator, which emits deep-blue photons. Its photoluminescence emission peak (434–436 nm) and the decay time is of the order of 3 ns, as well as it is resistant to harsh environment. In this study, thin PEN film with high neutron cross section dopants was used for the thermal neutron detection. Iron boride, lithium tetraborate and lithium metaborate layers were coated on a 125 µm PEN film. Reaction particles from the boron neutron and lithium neutron reaction were detected by scintillation in PEN, and photomultiplier (PMT) pulses were registered and analysed. Energy deposition in the film samples was calculated using MCNP6 code taking into account losses in the source and air gap for the alpha particle source and incomplete energy deposition for the electrons. It was found that a small quantity of particles from the thermal neutron reaction could be detected in the strong neutron, gamma ray and recoil proton background.