ABSOLUTE MEASUREMENT OF IR-192

The radioactivity of Ir-192 has been measured with several different t echniques. The conventional 4 pi beta-gamma coincidence results were c onfirmed by the 4 pi beta-gamma(Ge) spectroscopic coincidence method, in which a large HPGe detector [120% cf. 3 '' x 3 '' NaI(T1)] was used to avoid low gamma-efficiency problems. A well-type NaI(T1) crystal w as applied for the 4 pi gamma counting, which was very effective for s uch multi-gamma emitting nuclides. These results were in good agreemen t, and those of preliminary relative measurements with ionization cham bers and gamma-spectrometry were also in reasonable agreement. (C) 199 8 Elsevier Science Ltd. All rights reserved.