Abstract: Information about a radiation source’s position is essential for methods of simultaneous detection of neutrons and photons. The detection system that is capable of spatial mapping of radiation in two dimensions was developed. A single Cs2LiYCl6:Ce³⁺ detector enriched in ⁷Li isotope (C7LYC) was equipped with a hybrid dual-mode rotational collimator. The collimator was designed as a coded aperture (a modified uniformly redundant array) using lead and plastic components. C⁷LYC scintillator enables segregation of neutron signals from photon signals, and neutron and photon energy measurements. Radiation measurements were performed at different angular positions of the collimator using a single detector. Maximum likelihood expectation technique was utilized to generate the image of an assayed radiation source. Time encoded imaging of neutron and photon sources was demonstrated using this detection system.

Keywords: C⁷LYC, Pulse shape discrimination, Gamma spectroscopy, Neutron detection, Dual mode hybrid collimator, Time encoded imaging.