Ferrous Ammonium Sulphate Dosimeter Chemical Yield Determination for Dose Measurement Standardization in High Energy Photons

The radiation chemical yield G(Fe3+) of the ferrous ammonium sulphate (Fricke) dosimeter has been measured in high energy photon beams. The calibration of the dosimeters was performed at energies of 60Co gamma radiation, 6 and 18 MV photons. The reference absorbed dose in a water phantom was measured at a reference depth using an ionization chamber calibrated in terms of absorbed dose to water. The Fricke solution was placed in Pyrex ampoules. The values of G(Fe3+) thus obtained, for a solution with sodium chloride, are: 1.598 (±0.012), 1.597 (±0.020) and 1.603 (±0.020) μmol/J at 60Co, 6 and 18 MV photon beams, respectively. (author)