Radioactive ${}_{}{}^{40}{}_{}{}^{}\mathrm{Cl}$ was produced by the reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}\mathrm{}(n,p)\mathrm{}{}_{}{}^{40}{}_{}{}^{}\mathrm{Cl}$ through bombardment of a liquidargon target with 14.9-MeV neutrons. $\gamma$ rays were observed with 6-, 15-, and 35-cc Ge(Li) crystal detectors, and with two NaI(Tl) crystal detectors in coincidence. Twenty-three $\gamma$ rays with energies from 262 to 6334 keV were assigned to transitions in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$. The $\beta$-ray relative intensities were deduced from the relative intensities of the $\gamma$ rays, and $log\mathrm{ft}$ values were calculated. It was concluded that all levels in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ up to and including the 3518-keV level have even parity. Seven levels from 3681 to 6335 keV in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ have odd parity and spin of 1, 2, or 3. The ground energy level of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Cl}$ has spin-parity $2^{-}$, if in fact the 3681-keV level of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ has spin-parity $3^{-}$.

• Received 11 February 1970

DOI:https://doi.org/10.1103/PhysRevC.2.948