Toward complete spectroscopy using β decay: The example of Cl32(βγ)S32

E. Aboud, M. B. Bennett, C. Wrede, M. Friedman, S. N. Liddick, D. Pérez-Loureiro, D. W. Bardayan, B. A. Brown, A. A. Chen, K. A. Chipps, C. Fry, B. E. Glassman (+13 others)
2018 Physical Review C  
32 Cl is a neutron-deficient isotope with a β-decay half-life of 298 ms and a spin and parity of J π = 1 + . Previous measurements of 32 Cl β-delayed γ-rays have yielded a β-decay scheme with twelve β-decay transitions, contributing to studies of nuclear structure and fundamental symmetries. Those experiments have been limited to the observation of 32 S states with J π = 0 + , 1 + , 2 + . Purpose: To search for new β-delayed γ-rays and β-decay transitions of 32 Cl to 32 S. Methods: A
more » ... of 32 Cl β delayed γ decay has been performed using the Clovershare array of high-purity germanium detectors at the National Superconducting Cyclotron Laboratory. Results: By acquiring the highest-statistics 32 Cl β-delayed γ-ray spectrum to date and exploiting a new sensitivity to γ-γ coincidences, this experiment has allowed for the observation of nine previously unobserved β-delayed γ-ray transitions leading to the inference of five β-decay transitions never before observed in 32 Cl β-delayed γ decay. The set of observed states includes negative-parity states for the first time. By combining the new information with data from previous work, the lifetimes and partial widths of the 8861 and 9650-keV states of 32 S have been determined. In addition, the 31 P(p,α) 28 Si resonance strength of the 9650-keV state has been limited to ωγ < 9.8 meV, which is an improvement over direct measurements. Conclusion: An enhanced decay scheme has been constructed. Most of the excited bound 32 S states that would correspond to allowed and first-forbidden β decay transitions have been observed, demonstrating the potential of β decay experiments to approach complete spectroscopy measurements at the next generation of radioactive beam facilities. The observed positive-parity levels are well matched by sd shell-model calculations.
doi:10.1103/physrevc.98.024309 fatcat:4dcowmpynzh5dn2jewoxqep3wy