Measurement of the Response Function of a Custom Plastic Scintillator Using Monoenergetic Neutron and Proton Sources

An experimental study was carried out to determine the light output function of the protons deposited energy in a custom triple discriminating (thermal neutrons/fast neutrons/gamma rays) plastic scintillator. Two response functions of the plastic scintillator were measured and compared using monoenergetic sources of either neutrons or protons. The response function to neutrons was measured at the IRSN Amande facility in CEA Cadarache using the monoenergetic neutron generator. The response matrix was based on six incident neutron energies that ranged from 953 keV to 14.8 MeV. The low-energy threshold for detecting neutrons is evaluated at around 1 MeV. The second response function was measured utilizing the Cyrcé cyclotron at IPHC located in Strasbourg. The response matrix was obtained based on six incident proton energies ranging from 5.9 to 19.97 MeV. The response function measured using monoenergetic neutrons has a nearly rectangular shape that extends from the light output of the low-energy discrimination threshold to the light output of the full incident neutron energy. The pulse height spectra acquired with monoenergetic protons exhibit a Gaussian shape, where the average value corresponds to the light output of the incident protons' energy. The exponential curve used to fit the light output data acquired from the monoenergetic neutron field generator aligns well with the light output data obtained from the monoenergetic proton beam.