Response of a telescope proton recoil spectrometer based on a YAP: Ce scintillator to 5–80 MeV protons for applications to measurements of the fast neutron spectrum at the ChipIr irradiation facility

A telescope proton recoil spectrometer consisting of a 500μm thick silicon detector and a 2.54 cm × 2.54 cm YAP:Ce inorganic scintillator has been developed to measure the neutron spectrum at ChipIr, a fast neutron beam line that has recently started operations at the ISIS neutron source in the UK. The spectrometer has been tested with protons in the range 5–80 MeV at the INFN-LNS cyclotron accelerator. The light yield of the YAP scintillator to protons has been characterized relative to gamma-rays of same energies and found to scale linearly with the proton energy in the whole range. Background rejection using a ΔE-E technique by combining data from the silicon and YAP:Ce detectors has also been tested successfully.