Investigation into neutron damage of EJ-299 and EJ-200 plastic scintillators

The advent of new plastic scintillator formulations opens avenues of application in terms of neutron-gamma discrimination. As a consequence, the likelihood that these detectors will be subject to regions of significant neutron flux is high. In order to study the tolerance to radiation damage a number of samples of both EJ-299 and EJ-200 plastic scintillator were irradiated with fast neutrons using a neutron flux of up to 2.2×10¹² (+/-5.6%) n/cm²/s. All samples were cut to a size of 30 mm × 30 mm × 15 mm and polished prior to irradiation. The radiation response of the samples was measured by performing standard gamma spectroscopy on lab sources. The optical emission spectra were analysed by irradiating each sample with an 80 kV X-ray beam from a Hamamatsu X-ray tube. Optical spectroscopy of the scintillation light was recorded using an Ocean Optics QE6500 spectrometer, and the opacity of the irradiated samples was measured with a Cary 5000 spectrophotometer. The effect on the peak emission wavelength, optical intensity, and spectral shape of the scintillation was determined as a function of neutron fluence.