Well-developed deformation in 42Si

S. Takeuchi , M. Matsushita , N. Aoi , P. Doornenbal , K. Li , T. Motobayashi , H. Scheit , D. Steppenbeck , H. Wang , H. Baba , Dominique Bazin , L. Caceres (1) , H. Crawford , P. Fallon , R. Gernhäuser , J. Gibelin (2) , S. Go , S. Grévy (1) , C. Hinke , C. R. Hoffman , R. Hughes , E. Ideguchi , D. Jenkins , N. Kobayashi , Y. Kondo , R. Krücken , T. Le Bleis , J. Lee , G. Lee , A. Matta (3) , S. Michimasa , T. Nakamura , S. Ota , M. Petri , T. Sako , H. Sakurai , S. Shimoura , K. Steiger , K. Takahashi , M. Takechi , Y. Togano , R. Winkler , K. Yoneda

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 LPCC - Laboratoire de physique corpusculaire de Caen
3 IPNO - Institut de Physique Nucléaire d'Orsay

Excited states in 38,40,42Si nuclei have been studied via in-beam gamma-ray spectroscopy with multi-nucleon removal reactions. Intense radioactive beams of 40S and 44S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled gamma-gamma coincidence measurements. A prominent gamma line observed with an energy of 742(8) keV in 42Si confirms the 2+ state reported in an earlier study. Among the gamma lines observed in coincidence with the 2+ -> 0+ transition, the most probable candidate for the transition from the yrast 4+ state was identified, leading to a 4+_1 energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2+_1 and 4+_1 states indicates well-developed deformation in 42Si at N=28 and Z=14. Also for 38,40Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for 42Si, the results show a rapid deformation development of Si isotopes from N=24 to N=28.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

S. Takeuchi, M. Matsushita, N. Aoi, P. Doornenbal, K. Li, et al.. Well-developed deformation in 42Si. Physical Review Letters, 2012, 109, pp.182501. ⟨10.1103/PhysRevLett.109.182501⟩. ⟨in2p3-00721241⟩