Numerical optimization of Rhodium Self-Powered Neutron Detector

Self-Powered Neutron Detector (SPND) has been widely used in reactors to monitor neutron flux due to its adaptability for in-core severe environment. As a typical representative, SPND with Rhodium as its emitter has been modeled in the frame of Geant4, which is good at tracing the history of the particles in simulation and very appropriate for directly simulating SPND's working mechanism. First of all, simulation model has been validated by simulating one existing typical SPND. Then, the performances' dependences on the detector's dimensions have been studied systematically. Finally, SPND's geometries have been optimized and the suggested optimal design gives a neutron sensitivity of 1.03 × 10−19 A·cm2·s and a ratio of prompt current of 80.22%. Additionally, this work is also helpful to optimize all the SPNDs for customized requirements.