Standardization of radionuclides multi-gamma emitters 166mHo and 72Ga and determination of its gamma intensities by decay

In the present work, the multi-gamma emitters 166mHo and 72Ga have been measured by 4πβ-γ coincidence technique. The calibration system is composed of a 4π gas-flow proportional counter coupled to a pair of NaI(Tl) crystals. Both radionuclides were measured by using two gamma discrimination windows, namely (629.9 + 834.2) keV and (2201.6 + 2507.7) keV for 72Ga and 184.4 keV and (711.7 + 830.5) keV for 166mHo. The methodology recently developed by LMN (Laboratorio de Metrologia Nuclear) for simulating all detection processes in a 4π(β,X)-γ coincidence system by means of the Monte Carlo technique was applied to the measurements of both radionuclides, and the predict behavior extrapolation curve was compared with the experimental data. The results obtained were in good agreement within the experimental uncertainty. The emission probabilities per decay of the most intense y-ray in the decay of 166mHo and 72Ga were measured by means HPGe spectrometer system, which was previously calibrated with standard sources of 57Co, 60Co, 54Mn, 133Ba, 24Na, 152Eu and 241Am previously standardized in the 4πβ-γ system. All the uncertainties evolved were treated rigorously, by means of covariance analysis. (author)