Calculational model for self-powered neutron detector

A calculational model is presented for the self-powered neutron detector of the type used in nuclear reactor cores. The model accounts for the neutron capture rate for beta-decaying nuclei, the electron escape probability from the emitter of the detector, and the effect of the insulator on the sensitivity of the device. Calculated unit sensitivities to thermal neutrons are presented as functions of emitter diameters and insulator thicknesses for rhodium and vanadium emitters having cylindrical geometries. The calculated values are compared with experimental values.