PROPERTIES OF CL-34 LEVELS FROM S-33(P, GAMMA)CL-34 REACTION

Six resonances in the S33(p,γ)Cl34 reaction in the range Ep=1.0-1.3 MeV have been investigated in order to obtain information on resonance and bound-state properties of Cl34. Revisions of previously reported γ-ray decay schemes of all six resonances were required as a result of measurements with a 40-cc Ge(Li) detector. The decay properties of 11 bound states below Ex=4.0 MeV were determined. Significant changes from previous results were found for the 0.665-, 3.545-, and 3.598-MeV levels. The 0.665-MeV level was observed to decay only to the ground state, as opposed to the branching ratio 80:20 for decay to Cl34 (0) and Cl34 (1) reported from earlier NaI (Tl) work. Transitions were observed from resonance levels to both the 3.545- and 3.598-MeV levels, which were unresolved in previous γ-ray work. The lower level was observed to decay only to the 0.147-MeV (3+) level, while the upper level branches to the 0.147- and the 2.720-MeV level. Angular-correlation measurements at the 1165-keV resonance yield J=3 4, respectively, for the resonance and 2.376-MeV levels. The latter result is consistent with a previous prediction of Jπ=4+ from shell-model calculations. The 2.376→0.147 (3+) transition is highly mixed dipole-quadrupole (δ=-6.3-3.2+2.0) in reasonable agreement with a value δ=-2.7 calculated with published wave functions. Angular distribution and strength measurements at the 1266-keV resonance yield Jπ=2+1, respectively, for the resonance and 0.665-MeV levels. Similar measurements at the 1071-keV resonance yeild Jπ(Res.)=1+2±. For several other levels, limitations on the possible spin assignments are obtained from transition speed considerations. Lower limits for the lifetimes of six bound states were obtained from Dopplershift attenuation measurements at four resonances. New, more precise, values for the excitation energies of 12 bound states of Cl34 were obtained from Ge(Li) spectra. The S33(p,γ)Cl34 reaction Q value was found to be Q=5140.3±1.5 keV. This value is 15±6 keV lower than the value Q=5155±5 keV given in the 1964 Mass Tables. The possible location of members of the (d32f72) odd-parity spectrum is discussed. © 1969 The American Physical Society.