A small-scale neutron dosimetry intercomparison between Essen, Amsterdam and Edinburgh

An intercomparison of neutron dose measurements was made at Essen by visiting groups from Amsterdam and Edinburgh to compare measurements of the neutron and photon absorbed doses in a phantom in the neutron beam. An intercomparison of the photon calibration of the tissue-equivalent chambers was also made. Differences in the measurements of total absorbed dose in the neutron beam of up to 4.7% were observed. These were consistent with the observed differences in the photon calibrations. A summary is given of the different calibration methods used by each group. Greater discrepancies (up to 18%) were seen in the measurement of the photon contribution to the absorbed dose in the neutron beam and these were in part due to insufficient shielding of the GM counter from thermal neutrons.