PHOTOPARTICLE PRODUCTION IN SOLID-STATE DETECTORS USED FOR NEUTRON DOSIMETRY IN THE PRESENCE OF PHOTONS

Photon-induced neutron, proton and alpha particle production in polyethylene and CR-39 has been estimated for the photon energy range of 2-30 MeV, using our previously established methods and photonuclear cross-section data for hydrogen, carbon and oxygen. The rarer isotopes of the constituents of CR-39 and polyethylene, namely H-2, C-13, O-17 and O-18, have been taken into account. Neutrons and protons are produced in polyethylene and CR-39 for photon energies above 2.2 MeV, the (gamma,np) threshold for H-2. Photoparticles produced in these materials may need to be taken into consideration when using them for neutron dosimetry in the presence of photons in this energy range, especially when the neutron flux is several orders of magnitude less than that of the photons.