U234excited states fed in theβdecay ofPa234

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Abstract
The decay of radiochemically separated Pa234 (UZ) sources has been reinvestigated by means of single and γ-γ coincidence spectrometry using planar and high efficiency coaxial HPGe detectors. Of the 330 γ rays observed in the 40–2100 keV energy range, of which 140 are new, more than 310 γ rays are accommodated in an improved U234 level scheme, accounting for 98% of the Pa234 β decay; of the 77 excited states observed here, 37 had not been previously found in this decay. Within the framework of the collective model of strongly deformed nuclei, couplings between the collective positive parity Kπ=01+ (g.s. band), 02+, 21+, 03+, and 22+ bands are estimated from the perturbed transition probabilities and the distortions to the adiabatic energy systematics. The Coriolis interaction weakly coupling the Kπ=0−, 1−, and 2− octupole bands was evaluated consistently by a fit to the experimental energy levels. Several new levels and a tentative Kπ=3+ band (at 1770 keV) are discussed in terms of Nilsson orbitals assignments.