A measurement of the mass of 39Sc

Abstract

The mass of the proton-rich nucleus 39Sc has been derived from a measurement of the Q-value of the 40Ca(14N, 15O)39Sc reaction at a beam energy of 102.5 MeV and mean reaction angle of 6°. A value of -27.67 ±0.03 MeV was obtained for the Q-value, implying a mass excess of -14.19 ± 0.03 MeV for the ground state of 39Sc, which is therefore unbound to proton emission by an energy of 580 ±30 keV. There is some evidence for an excited state in 39Sc at an energy of 950 ±keV. This state is tentatively identified as the analog of the 1.27 MeV 3 2- state in 39Ar. The cross sections to the 1 2+ and 5 2+ states in 15C confirm an earlier suggestion that this reaction is well suited to the observation of proton-rich nuclei via direct transfer reactions having very negative Q-values. Show more