Comparison of Hp(0.07, 0°) for 90Sr/90Y Beta Radiation with CaF2:Dy TLD-200 Dosimeters

The results for the comparison of Hp(0.07,0°) in 90Sr/90Y, carried out by the SSDL-ININ (pilot) and CPHR, are presented. Four calibration curves (CCs) are constructed with 32 TLD-200 dosimeters irradiated on a PMMA phantom. The CCs, TLD's Response RTLD (nC) vs Hp(0.07,0°), are in the range 0.2-100 mSv. The SSDL-ININ rate Hp(0.07, 0°) value is (43.85 ± 0.57) µSv s-1 obtained with a primary extrapolation chamber serial 040. These same dosimeters are irradiated at the CPHR with a rate of Hp(0.07, 0°) = (14.94 ± 0.36) µSv s-1, also calibrated with another primary standard extrapolation chamber serial 105. After irradiation at CPHR, the dosimeters are returned to the SSDL-ININ for reading, and then irradiated again to construct the fourth CC (CC4). The comparison is based on a modification of the standard ANSI/HPS N13.11-2009, where the reference values are [Hp]ININ,ref. For the values of [Hp]CPHR the statistics bias B = 0.002; standard deviation, S = 0.099; and tolerance level L = 0.099 are determined. The homoscedasticity test is performed for the variances associated to the mean performance quotientB.