Figure 7

Illustration of the environmental radiation source normalisation methodology. The arrows indicate the direction of neutrons, which are recorded in the sphere in a track length estimator tally to compute a normalisation factor. The source was sampled on a 10 m \(\times\) 10 m plane surface, positioned 5 m above the origin of the coordinate system. All models were oriented such that the centre of the monitor was at the origin. Using a void geometry with a sphere cell of radius 2 m centred on the origin, the neutron source definition is sampled and the cell volume averaged neutron flux estimate over the sphere is recorded.