Calibration of Self-Powered Neutron Detectors

The thermal neutron sensitivities of ²³¹Rh self-powered neutron detectors were measured in a 1-MW(thermal) pool-type reactor. Measured relative sensitivities are statistically compared against calculated relative sensitivities. The latter are derived from a formula for the ratio of the lateral surface area of the rhodium emitter of a given detector to the lateral surface area of the rhodium emitter of a reference detector. Least-squares linear regression analysis of relative sensitivity versus surface area shows that the calculational method yields the same calibration results as the measured method with a high degree of accuracy.