Proficiency Test of the SSDL-Inin-Mexico for the Calibration of Well-Type Chambers With HDR 192ir Sources Using Two Different Dosimetry Codes of Practice for the Determination of Reference Air Kerma Rate K̇r

Abstract

The results of the comparison between SSDL-ININ and SSDL-CPHR (pilot laboratory) demonstrates the competence of the SSDL-ININ for the performance of the KR in 192Ir. The RININ/CHPR ratio for the calibration coefficients is 0.989 ± 0.005. The comparison uses three SI-HDR 1000-Plus as transfer chambers, series: A02423, A941755 and A973052. CPHR used a secondary standard PTW 3304 chamber, s/n 154, calibrated at PTB and ININ employed a secondary standard SI-90008 s/n A963391, calibrated at NPL. To determine KR, the SSDL-CPHR used the IAEA TEC-DOC-1274 and the SSDL-ININ used the IPEM (UK) code of practice. The latter uses a correction factor by source's geometry, ksg. The results show that both codes are equivalent; however, for the use of well chambers in the highlands or in locations with reduced atmospheric pressure, it is needed to apply an additional factor k'P, or, to design a well chamber with air-equivalent walls for the application of the conventional kPT.

The dependence of N KR versus K R: the initial, thermal, volumetric recombination and screening effect on the efficiency of collected charges on the calibration of si HDR1000 plus well chambers with 192Ir HDR sources *

“…(a) k PT air density corrections given the atmospheric influence quantities: P and T, (b) Failure of the k PT owing to the non-equivalence of the chamber walls with the air, both for lowenergy 125 I and 103 Pd [5,6] and high-energy isotopes such as 192 Ir, [5,7]. In fact, when the interface air-chamber's wall-air cavity there is no air-equivalent material for the wall (C 552 plastic: it is an air-equivalent formulation that consists of polyvinylidene fluoride, carbon black, and silica, which makes it particularly appropriate in the measurement air kerma.)…”