The absolute counting of I-125

The Institute of Nuclear Energy Research (INER) participated in a compariso n of activity organized by the Electrotechnical Laboratory (ETL, Japan). At this occasion, I-125 was measured. Seven laboratories of the Asia Pacific region carried out measurements and ETL, at the same time, took part in BIP M SIR measurements. Two measurement methods developed by INER, the sum-peak coincidence counting with two 76 x 76 mm NaI(Tl) detectors and the 4 pi e- X coincidence counting technique with efficiency extrapolation, were used t o standardize the activity of I-125. The results from the two methods are 2 .6% different. INER's results agree with the results of the regional compar ison and the BIPM SIR. (C) 2000 Elsevier Science Ltd. All rights reserved.