Intercomparison of Absorbed Dose to Water Measurements for 60Co Gamma Rays using Fricke, Alanine and Radiochromic Dye Film Dosimetry

Measurements of absorbed dose at 5 cm depth in a 30 X 30 X 30 cm 3 water phantom have been performed using three independent dosimetric techniques: Fricke, alanine and radiochromic dye film (GafChromic HD-810). The measurements were carried out in the secondary standard dosimetry laboratory at ININ Mexico using a collimated 60 Co gamma source with a radiation field of 10 × 10 cm 2 at the phantom front surface. The source to phantom distance was set at 100cm. The reference absorbed dose at 5 cm depth in the water phantom was obtained using a 0.6 cm 3 ionisation chamber. The absorbed dose to water for the test dosimetry techniques was around 100 Gy. The deviations of the dose obtained from these dosimetry techniques were within 4%. The reasons for these deviations are discussed.