Simulating response of C$^7$LYC detector for fast neutron detection

A detailed Monte Carlo simulation code has been developed to study the response of $^7$Li-enriched Cs$_2$LiYCl$_6$(C$^7$LYC) detectors using the Geant4 simulation framework. The intrinsic efficiency of a 1” thick shell of C$^7$LYC material is calculated for fast neutrons in the range 0.5 - 8 MeV and are compared with prior MCNP simulations and data. Contributions from $^{35}$Cl(n,p) and $^{35}$Cl(n,$\alpha$) reactions are differentiated and studied in the simulated spectrum. The detector efficiency as a function of energy is deduced using different cross-section evaluations and recent experimental measurements. Light output for both 3" x 3" and 1" x 1" C$^7$LYC detectors were simulated according to the Birks equation, with parameters deduced from experimental spectra. From this quenching factors for the light output of alphas and protons in C$^7$LYC are calculated from calibrated gamma-ray spectra. The simulations will be discussed in the context of benchmarking C$^7$LYC as an emerging scintillator for fast neutron measurements.