Abstract
The - and -ray radiation following the decay of Ba142 to La142 were measured in experiments in which end-point energies, coincidences, -ray singles, t coincidence, and t() angular correlation data were collected. The Ba142 activity was produced by on-line mass separation from the U235(nth, f) reaction. A level scheme for odd-odd La142 was deduced from coincidence information that includes 90 rays which are placed among 23 levels. A 0.870.17 s isomeric state was established at 145 keV. The Q value of 220025 keV was determined from coincidence data. Beta-ray intensities and logft values have been evaluated, and along with internal conversion and angular correlation measurements, yielded spin-parity assignments for a number of levels. The low-lying levels were compared with level schemes projected from multiplet parabolas computed using parameters extracted from parabolic fits in La140 and Pr142. RADIOACTIVITY Ba142 [from U235(nth, f)] measured E, I, E, k, t coincidence, t() angular correlation, coincidence; HPGe and detectors; L142A deduced levels J, I, logft, level lifetime, and Q. Mass separated Ba142 activity. © 1983 The American Physical Society.