Standardization of 125I and 109Cd by the photon-photon coincidence method in PTKMR-BATAN

Abstract:

A photon-photon coincidence system was constructed for the standardization of (125)I and (109)Cd in PTKMR-BATAN, Indonesia. Two NaI(Tl) detectors of 76 mm diameter × 6mm thickness with 0.5mm aluminum window were used, which were positioned approximately symmetrically to the source holder.

The electronic chain was almost the same as for a 4πβ-γ system. The CANBERRA Multiport II multi channel analyzer was used for energy calibration and a Philips type PM3092 oscilloscope for visualization of the pulses. A polyethylene plastic was used as the source substrate for the (125)I and (109)Cd samples. The activity of a (125)I solution was measured by the photon-photon coincidence and the efficiency extrapolation method (Schrader and Walz, 1987), whereas the activity of a (109)Cd solution was determined by a tracer method using (125)I (Schrader, 2006). The result of the (125)I activity showed good agreement with the result of measurements using a calibrated ionization chamber, and the result of (109)Cd also showed good agreement with the measurements result using a LEGe detector.

Pujadi Marsoem, Gatot Wurdiyanto, Hermawan Candra

Center for Technology of Radiation Safety and Metrology, National Nuclear Energy Agency, Jalan Lebak Bulus Raya No.49, POB 7043-JKSKL, Jakarta Selatan 12070, Indonesia. 

(Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine)