Radiation imaging with a rotational modulation collimator (RMC) coupled to a Cs₂LiYCl₆:Ce (CLYC) detector

As an attempt to develop a gamma-ray/neutron dual-particle imager, we employed a rotating modulation collimator (RMC) coupled to a pulse shape discrimination-capable scintillator. We performed fundamental simulations on the proposed RMC system utilizing a CLYC detector to verify the basic properties of the RMC system and to optimize the computing methods for the Monte Carlo simulation. We obtained batches of modulation patterns for various source locations by using Monte Carlo N-Particle simulations, and we studied the characteristics of the modulation patterns, such as the rotational effect, the shift effect, and the symmetric effect. We compared simulated modulation patterns with those obtained from the mathematical model of the RMC system to investigate the feasibility of identifying the source location correctly based on the simulated patterns. When a source was located in the far-field region, the modulation patterns showed good agreement between the Monte Carlo simulation and the mathematical model. The results hold promises for reconstructing gamma and neutron images of radioactivity by using a RMC system on a CLYC detector.