Optimisation of the neutron coincidence process for the assay of fissile materials

The detection and measurement of groups of associated pulses in a train otherwise comprised of randomly timed individual pulses is an important technique for assaying fissile materials. A well known and effective method of doing this is based on the use of shift registers. An alternative method was suggested in a previous paper and found theoretically to give a measurement with a smaller standard deviation. Both methods are well suited to Monte Carlo simulation and this has been successfully used to confirm the theoretical result. (orig.)