Properties of P30 Levels from the Si29(p, γ)P30 Reaction. I

Abstract
γ-ray decay schemes of seven resonances in the Si29(p, γ)P30 reaction in the range Ep=7001750 keV have been studied in order to gain additional information on properties of resonant and bound levels of P30. The results also provide necessary information for the analysis of γ-ray angular-correlation and polarization measurements, which are in progress. Singles and coincidence spectra were obtained at each of the resonances at Ep=730, 917, 1302, 1470, 1505, 1686, and 1748 keV (all±2 keV) using large-volume NaI (Tl) detectors and a Ge(Li) detector. The resonance strengths were measured relative to the strength of the resonance at Ep=416 keV in the same reaction, which is known from previous work. Consistent resonance decay schemes were derived, along with decay schemes of lower-lying bound states which, in many cases, differ considerably from previously available information. New results, or results significantly different from earlier reports, were obtained for the decay properties of the 3.02-, 3.74-, 3.93-, 4.14-, 4.18-, 4.23-, 4.43-, 4.50-, 4.62-, and 4.92-MeV levels of P30. The existence of a weak transition from the 4, 4.23-MeV level to the 1+ ground state is shown. Another unusual transition found is one from the 3, 4.92-MeV level to the 1+, 0.709-MeV level. The energies of 17 bound levels of P30 were determined from the Ge(Li) data to a greater accuracy than heretofore available. Evidence is found for a previously unreported level at 4.468±0.003 MeV, which is proposed to be the J=0, T=1 analog of the 3.79-MeV level of Si30. The decay schemes of the Ep=730, 917, and 1302-keV resonances indicate they are quite pure T=0 levels. The new value Q=5.597±0.003 MeV for the Si29(p, γ)P30 reaction was derived from the Ge(Li) spectra.