Optimizing the collimator/shielding configuration of the NG-430 neutron generator

Computer optimization of the collimator and shielding of the NG-430 neutron generator at the Institute for Nuclear Research, Russian Academy of Sciences, is performed. The purpose of the optimization is to reach an acceptable value of the ratio Q between the neutron fluence in the investigated target (the signal) and the neutron fluence in the area of the detecting equipment (the background). The fluences of fast neutrons in the target and detectors are calculated by the Monte Carlo method. The influence of the walls of the experimental hall is taken into account. The optimal configuration of the assembly that provides the required Q value is found.