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.