Implementation of water calorimetry in a 180 MeV scanned pulsed proton beam including an experimental determination of k_Q for a Farmer chamber

Water calorimetry, in which the temperature rise induced by the absorbed dose in water is measured, is an important technique for establishing the absorbed dose under reference conditions. In the present work, water calorimetric measurements have been performed for the first time in a 180 MeV scanned pulsed proton beam and the absorbed dose has been compared with the results obtained using two NE2571 Farmer chambers. The present investigation has shown that water calorimetry is feasible in a high-energy scanned pulsed proton beam, and as a result of the work the beam quality correction factor, k_Q, was determined for the two NE2571 ionization chambers used. When comparing the result (1.032 ± 0.013) with a previously obtained result in a passively scattered proton beam of similar energy, a 1.1% deviation was obtained. This deviation is not significant considering the combined uncertainties of the two experimental determinations of k_Q.

The full article is available here (free to read).