Decay of Radioisotope Ga⁶⁸

Abstract

The decay of Ga⁶⁸ (68 min) has been investigated with beta- and gamma-ray scintillation spectrometers. Two beta-ray components with endpoint energies of 1.95±0.03 MeV, and 0.88±0.05 MeV are observed. Gamma-rays of 0.80±0.02, 1.08±0.01, 1.24±0.02 and 1.88±0.01 MeV are confirmed. Angular correlation of the 1.08–0.80 MeV gamma-ray cascade in Zn⁶⁸ have been measured. The Legendre polynomial expansion coefficients are determined to be A₂=−0.237±0.056 and A₄=0.39±0.062. The measured correlation establishes the spin sequence to be 2–2–0, with a quadrupole-dipole mixing ratio δ of −(4₋₂⁺³) for the 0.80 MeV gamma-ray. The results of the angular correlation work together with the allowed nature (logft=5.7) of the electron capture decay to the 1.88 MeV level fix the spin and parity of this level to be 2+. The results are consistent with the systematics given by Sakai for low excited of even states of even-even nuclei.