BETA DECAYS OF C15 F17 AND F20

β-ray branches in the decays of C15, F17, and F20 have been investigated by measuring the γ-ray spectra from these activities with a 22-cc Ge(Li) detector. The activities were formed by deuteron bombardment of various targets with a chopped Van de Graaff beam. Previously observed C15 β-ray branches to the 8312-and 9052-keV states of N15 were confirmed, the branches being [(5.0±0.6)×10-4; logft=5.06±0.06] and [(3.5±0.5)×10-4; logft=3.99±0.07], respectively, and one new branch was found leading to the 7300-keV state [(0.8±0.2)×10-4; logft=6.82±0.13]. There is also weak evidence for a β-ray branch to the 8570-keV state of N15[≤2.8×10-4; logft 5.0]. The limit on the β branching of F17 to the 871-keV state of O17 is <3.4×10-4, corresponding to logft>5.6. In F20 decay, lifetime measurements have confirmed that a weak 3.3-MeV γ ray is associated with this activity resulting from a β-ray branch to the 4.97-MeV state of Ne20[(1.7±0.3)×10-4; logft=6.89±0.08]. From simultaneous measurements on the γ rays occurring in F20 and B12 decays, the energy of the F20 γ ray is 3334.3±0.7 keV, and thus Ne20 level has an energy of 4968.3±0.8 keV. © 1969 The American Physical Society.