A thermoluminescent dosimetry intercomparison in operational power station fields

A dosimetry intercomparison was held among the five agencies in Canada that are recognized by the Atomic Energy Control Board as competent to perform external dosimetry. Exposures of thermoluminescent dosimeter badges were made under operational conditions to radiation fields in Candu nuclear generating stations. Details of the method are described including the large, block-type phantoms (with a rotating front face so that all badges were equally exposed) and a small device to measure the depth-dose distribution. Thirty-six exposures (or "runs") were made, exposing 522 badges for periods of 1 h-2 d. Normalization between the runs was based on the absorbed dose at 1,000 mg cm-2 for each run, as measured by the depth-dose device. Using this method, the average relative readings for the five participants ranged from 1.01-1.40 (dimensionless).