Recherche de résonances isobariques analogues dans 32S AU moyen des réactions 31P(p, γ) 32S 31P(p, p) 31P et 31P(p, α 0) 28Si

Abstract

Fourteen resonance levels have been observed in a study of the 31P(p, γ) 32S, 31P(p, p) 31P and 31P(p, α 0) 28Si reactions in the proton energy range E p = 1240–1600 keV. Resonance strengths have been determined for thirteen resonances of the 31P(p, γ) 32S reaction. The γ-ray decay schemes often resonances have been studied by means of a Ge(Li) detector. Spin values of resonance levels and of some bound levels have been obtained or confirmed by γ-ray angular distribution measurements done at seven resonances. For the thirteen resonances of the 31P(p, p) 31P reaction the proton orbital momenta have been determined. By combining the information from the three reactions, spins, parities, total and partial widths have been obtained for twelve resonance levels. Strong Ml transitions have been observed at the E p = 1247, 1402, 1437, 1555 and 1581 keV resonances. Two T-mixed doublets are identified at E p = 1247 and 1472 keV, J π = 2 −, and at E p = 1402 and 1469 keV, J π = 3 −. The resonance levels at E p = 1437 and 1581 keV may be components of a third almost completely mixed doublet. The E p = 1555 keV resonance level has been assigned T = 1. The E p = 1411 keV, J π = 1 +, resonance level has been identified with a level previously observed in the β + decay of 32Cl. Strong E2 transitions similar to those observed in some other doubly even s-d shell nuclei have been observed between odd-parity levels of 32S.