Neutron and Gamma-Ray Effects on Self-Powered In-Core Radiation Detectors

A general calculational model describing the effects of neutrons and gamma rays on self-powered prompt-responding coaxial in-core radiation detectors is presented. The model accounts for external gamma-ray interactions within a detector and the subsequent emissions of Compton electrons and photoelectrons. The model also includes neutron-capture gamma-ray and internal-conversion electron emissions. The effect on a detector’s sensitivity of space charge within its insulator is considered. A pseudopotential on the central electrode is introduced to account for Z-dependent variations in the space-charge distribution. Calculated neutron and gamma sensitivities of several in-core detectors are compared with experimental sensitivities. The comparisons are sufficiently satisfactory to label the model as successful in its predictions.