The beta-decay energy $Q_{\beta }$ of the neutron-rich chlorine isotopes ${}_{}{}^{40}{}_{}{}^{}$,42Cl produced by fragmentation of a tantalum target with a 2-μA proton beam has been determined. Energies of the beta transitions to bound levels in the daughter nuclei were measured by means of a scintillation telescope in singles or in coincidence with a high-efficiency Ge(Li) gamma counter. The ${}_{}{}^{40}{}_{}{}^{}\mathrm{Cl}$ and ${}_{}{}^{42}{}_{}{}^{}\mathrm{Cl}$ inferred experimental mass excesses, -27.72±0.08 and -24.66±0.22 MeV, respectively, are compared to mass predictions.

• Received 19 July 1988

DOI:https://doi.org/10.1103/PhysRevC.39.992