Heat transport by material-dependent heating during absorption of radiation in the water absorbed dose calorimeter

Water absorbed dose calorimeters have been developed for the application as PTB standards for the dosimetry in radiation therapy with photon and elect ron radiation. Different detector types for various applications are availa ble. In this paper, heat conduction effects of "sealed" detectors are inves tigated, caused by the material-dependent temperature rise during the absor ption of Co-60-gamma-radiation in the detector walls and in the temperature probes embedded in water. The corresponding corrections can be minimized b y a proper design, allowing the resulting relative standard uncertainty to be kept well below 0.1%. (C) 1999 Elsevier Science B.V. All rights reserved .