Standardization and decay data of 68Ge/ 68Ga

Abstract

A gamma and an x-ray spectrometer, 4πβ—γ-coincidence equipment, liquid-scintillation counting (LSC) equipment and a calibrated ionization chamber (IC) have been used to determine the decay scheme parameters of 68Ga and the specific activity of a 68Ge/ 68Ga solution. The transition probability of the positron branch and the EC branch to the ground state of 68Zn, b 1 and e 1, the corresponding branches to the 1077 keV level of 68Zn, b 2 and e 2, the total emission probability of annihilation radiation from the 68Ga decay, p ann, and the gamma-ray emission probabilities of the quanta corresponding to the 1077 keV transition ( p 1077) and to some weak transitions were redetermined. The results are b 1 = 0.8785 ± 0.0012, e 1 = 0.0892 ± 0.0012, b 2 = 0.0129 ± 0.004, e 2 = 0.0193 ± 0.0004, p ann = 1.7829 ± 0.0022, p 1077 = 0.0322 ± 0.0003. The specific activity of a 68Ge/ 68Ga solution was determined with a relative uncertainty of 1% (1σ) using 4πβ—γ coincidence, LSC and IC measurements. A half-life of T 1 2 = (270.99 ± 0.19) d for 68Ge was obtained by measurements with an ionization chamber.