Neutron monitoring is required in many sectors, including Energy, Defence, Security and Healthcare. Performing accurate neutron dosimetry is an extremely difficult task and, existing area survey meters can over-respond by up to 1,000%in some intermediate energy regions.
It is very difficult if not currently impossible to replicate the energy dependence of dose in living tissue with a portable device, and thus the current assessment of dose in the workplace falls short in several important areas of the spectrum.
Having been overlooked for many years, research is now starting to take into account the directional distribution of the neutron work place field. The impact of not taking this into account has led to over conservative estimates of dose in neutron workplace fields. Research has been published proposing methodologies for a more accurate estimate of dose, taking into account both neutron energy and direction. This presentation provides a critical review of this existing research into directional survey meters.
The two primary methods reviewed are boron doped spherical scintillator with multiple photo multiplier tubes and a multi-detector device with semiconductors equally spaced around a polyethylene sphere. Theoretical analysis has been carried out on both methods to investigate the systematic errors that exist within the two designs to enable identification of how conservative the estimate of dose is. Following the outcome of the review further work into the development of a directional neutron survey meter is proposed.