This study proposes a new integral experiment method for the thermal scattering law (TSL) of metal hydrides using neutron imaging. Metal hydrides have been considered as a neutron moderator in small reactors, including microreactors and space reactors. for achieving higher neutron economy. TSL data of metal hydrides, such as CaH2 and ZrH2, are crucial for core neutronics characteristics, particularly the temperature reactivity coefficient. However, existing TSL data of metal hydrides are outdated and based on room temperature experiments.

The proposed method involves using neutron imaging to measure the brightness change of metal hydride samples under high-temperature conditions of up to 500°C. This approach allows for high spatial resolution of less than 0.1-mm measurements with smaller samples using this high resolution, making it easier to increase sample temperature. This study demonstrates that the brightness decrease observed as 16-bit grayscale in neutron imaging experiments correlates with temperature changes and can be reproduced by PHITS (Particle and Heavy Ion Transport code System) calculations, especially when using CaH2 TSL data. These results suggest that neutron imaging may be a viable method for integral experiments of TSL under high-temperature conditions.