Absolute Intensity Determination of the 140.5 KeV Gamma Ray of 99Mo, 99mTc

The absolute intensities of the 140.5 KeV gamma-ray of 99Mo and/or 99MTc in a nonequilibrium state, have been measured using Ge(Li) gamma spectrometer. In various literatures, these values were scattered ranging from 1.44% to 5.7%. In the present work, the results obtained are 0.0510±0.0016, 0.882±0.026 and 0.895±0.024 for 99Mo, 99mTc and 99Mo-99mTc in a equilibrium state, respectively. The absolute intensities of the 181.1 KeV and 739.4 KeV gamma-ray have also been measured, they are 0.0579±0.0016 and 0.119±0.003, respectively.