CHARACTERISTICS OF A ~(85)Kr BETA-PARTICLE SOURCE APPLIED IN SERIES 1 REFERENCE IRRADIATIONS OF ™DIS-1 DIRECT ION STORAGE DOSEMETERS

摘要

Characteristics necessary to specify an ISO 6980 Series 1 reference radiation field were determined for a commercially available ~(85)Kr beta-particle source, using a BEAM EGS4 Monte Carlo code. The characteristics include residual maximum beta energy, E_(res), and the uniformity of the dose rate over the calibration area. The E_(res) and the uniformity were also determined experimentally, using an extrapolation ionization chamber (EC) and a 0.2 cm~3 parallel plate ionization chamber, respectively. The depth-dose curve measured with the EC gave a value 0.62 MeV for the E_(res). Series 2 ~(90)Sr + ~(90)Y and Series 1~(85)Kr beta-particle sources calibrated for H_p(0.07) at the secondary standard dosimetry laboratory (SSDL) of STUK were used to determine the energy and angular responses of ™DIS-1 direct ion storage dosemeters. The averaged zero angle H_p(0.07) responses to the ~(90)Sr + ~(90)Y and ~(85)Kr reference radiations were 135 and 80%, respectively. The responses were normalized to 100%, H_p(0.07) response to ~(137)Cs photon radiation.