“Gamma Rays from the Proton Bombardment of Sulphur and the O+ Second Excited State of 32S”

Abstract

The analysis of gamma rays from natural sulphur, separated sulphur–32 and sulphur–34 bombarded protons up to 5.7 MeV was carried out. Excitation function of the 2.24 MeV gamma ray due to the transition (1st-ground state of 32 S) was measured. Resonances were found at Ep=4.77, 5.10, 5.35 and 5.60 MeV, which correspond to the excitation energies of 6.93, 7.24, 7.48 and 7.71 MeV of 33 Cl, respectively. Gamma rays were observed with a single and three crystal spectrometers. In addition, using gamma-gamma cascade coincidence and sum coincidence methods, energies and decay scheme were determined as follows: 32 S: 0.92 MeV (5th-2nd), 1.20 (6th-2nd), 1.54 (2nd-1st), 2.23 (3rd-1st), 2.24 (1st-ground) and ∼4.3 (3rd or 4th-ground). 34 S: 0.97 (7td-3rd), 1.17 (2nd-1st), 2.13 (1st-ground), 3.30 (2nd-ground), 3.91 (3rd-ground) and 4.11 (5th-ground). The 3.78 MeV gamma ray due to the transition (2nd-ground of 32 S) was not found. The angular correlation between the cascade gamma rays of 1.54 and 2.24 MeV shows good agreement with the transition of O + (E2)2 + (E2) + . Then the 2nd state of 32 S at 3.78 MeV has a spin of O + . This assignment agrees with the calculation of the j-j coupling shell model. With a three crystal spectrometer, nuclear pair from the 2nd state of 32 S at 3.78 MeV was searched. The intensity of the nuclear pair was about 2% or less of the 1.54 MeV gamma ray. The configurations of this O + second state and the ground state of 31 P are also discussed.