Subtractive gamma discrimination technique for neutron diamond detectors operating in mixed radiation fields

A detection system based on diamond detectors and subtractive discrimination was developed for the measurement of thermal neutrons flux distribution changes during rod drop transient at the VR-1 reactor. The detection system was modified to replace the pulse-shaped method used for discrimination. The electronics available at the department was not able to measure high count rates with the pulse shape discrimination method. Subtractive discrimination allows us to reduce the requirements in the signal processing area, as the shape does not need to be recorded, and therefore the digitizer performance can be significantly lower. For this reason, a pulse stretching amplifier was developed and tested.