CLLBC High Temperature Scintillation Characterization and Detector Integration

High-temperature detectors are required for nuclear material accounting measurements for some advanced reactor designs including molten salt reactors. The Cs2LiLa(Br,Cl)(6):Ce (CLLBC) scintillator is a dual-mode scintillator that shows excellent gamma detection along with the capability to discriminate gamma rays from neutrons and is available as a commercial product from Radiation Monitoring Devices Inc. (RMD). The energy resolution at room temperature (RT) is similar to 3.0% at 662 keV with a light yield of similar to 45 000 ph/MeV. The gamma-neutron pulse shape discrimination (PSD) figure of merit (FOM) is similar to 3.5 at RT. We investigated the gamma and neutron detection performance of CLLBC scintillators from 25 degrees C to 200 degrees C. The results showed a good light yield response for gamma events as a function of temperature while the light yield for neutron-capture events monotonically decreased from 100% to 76% at 200 degrees C. When integrated with a high-temperature photomultiplier, at 175 degrees C we obtained energy resolutions of 7.8% for 662 keV gammas and 4.2% for neutron-capture events, together with a PSD FOM of 0.74.

Automated summary

The Cs2LiLa(Br,Cl)(6):Ce (CLLBC) scintillator is a dual-mode scintillator that can detect gamma rays and discriminate them from neutrons. We investigated the gamma and neutron detection performance of CLLBC scintillators from 25 degrees C to 200 degrees C. The results showed that the light yield for gamma events responded well to temperature changes, while the light yield for neutron-capture events decreased from 100% to 76% at 200 degrees C. When integrated with a high-temperature photomultiplier, we achieved energy resolutions of 7.8% for 662 keV gammas and 4.2% for neutron-capture events at 175 degrees C, together with a PSD FOM of 0.74.