Contribution au développement d'un dosimètre de transfert pour les fortes doses, caractérisé au moyen d'un étalon secondaire

Abstract

RÉSUMÉABSTRACT The metrological parameters of a ferrous sulphate dosemeter are normally determined by comparison with primary standards. We have undertaken to evaluate these parameters using a secondary standard and the IAEA formalism for absorbed dose determination. Thus, we have determined with measurements the wavelength of absorption of the ferric ion (304 nm), the molar extinction coefficient e (218.7 ± 0.9) mol 1 m 2 and the radiochemical yield G (1.627 ± 0.04) 1(H> mol J" 1 . These values of c and G are respectively within 0.4% and 0.6% of the reference values recommended by the ICRU. The comparison of absorbed dose values derived from the ferrous sulphate dosemeter and the ion chamber has allowed to determine the detection limit of the Fricke dosemeter, which is around 20 Gy. Beyond this limit, the dosimeter as developed at the SSDL allows the determination of absorbed dose in water with a global uncertainty of ± 1.2%. For the countries who do not have primary standards, it is possible to undertake the control of doses used in radiation sterilisation using this type of dosemeter prepared and calibrated in a SSDL.