WATER CALORIMETER FOR MEASURING PHOTON-RADIATION ABSORBED DOSE RATES.

Recently, increasing attention has been given to methods of determining ionizing-radiation absorbed doses, in particular in dosimetry for radiation safety, in radiotherapy, and in monitoring effects on materials in the engineering use of radiation. The transfer from exposure dose to absorbed dose for photon radiation has been caused by difficulties in using the SI unit for exposure dose, Cu/kg. Two problems are discussed in relation to abandoning exposure dose; the first is choosing the quantities that should be measured by working instruments, while the second is that of standards and the calibration of instruments by means of them. The use of a water calorimeter is described. Reproducibility and measurement error are also discussed.