Heat Transfer Effects in a Water Calorimeter for Measuring the Absorbed Dose of Therapy-Level Radiation Beams

Published

October 1, 2007

Author(s)

Ronald E. Tosh, Huaiyu H. Chen-Mayer

Abstract

Water calorimetry that directly measures the temperature rise (at the mK level) due to radiation heating is used as a primary standard for therapy-level gamma-radiation beams. The temperature rise is measured at a given point in space where the spatial distribution of the absorbed dose is non-uniform, and therefore is subject to heat conduction and convection distortions that must be corrected to recover the accurate dosimetric value. Corrections are typically estimated using finite-element modeling of these processes analyzed in the time domain, which is sensitive to timing details of the source. By using periodic modulation of the radiation source and measuring an effective frequency response, a system transfer function of the calorimeter can be derived. This spectral technique provides a basis for assessing systematic errors for all radiation exposure times, extending the data usable range beyond the limit of the traditional time domain analysis.

Conference Dates

October 1, 2007

Conference Title

Comsol Multiphysics Conference

Pub Type

Conferences

Keywords

frequency domain analysis, radiation dosimetry, water calorimetry

Citation

Tosh, R. and Chen-Mayer, H. (2007), Heat Transfer Effects in a Water Calorimeter for Measuring the Absorbed Dose of Therapy-Level Radiation Beams, Comsol Multiphysics Conference (Accessed October 13, 2025)