First Lifetime Investigations of N > 82 Iodine Isotopes the Quest for Collectivity

We report on spectroscopic information and lifetime measurements in the neutron-rich 135,137,139I isotopes. This is the first lifetime data on iodine isotopes beyond N = 82. Excited states were populated in fast neutron induced fission of 238U at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid ν-ball spectrometer. The level schemes of the 135,137,139I isotopes are revised in terms of excited states with up to maximum spin-parity of (33/2+), populated for the first time in fast neutron-induced fission. We provide first results on the lifetimes of the (9/2+1 ) and (13/2+1) states in 137I and 139I, and the (17/2+1) state in 137I. In addition, we give upper lifetime limits for the (11/2+1) states in 135−139I, the (15/2+1) state in 137I, the (17/2+1) state in 139I, and reexamine the (29/2+1) state in 137I. The isomeric data in 135I are reinvestigated, such as the previously known (15/2+1) and (23/2−1) isomers with T1/2 of 1.64(14) and 4.6(7) ns, respectively, as obtained in this work. The new spectroscopic information is compared to that from spontaneous or thermal-neutron induced fission and discussed in the context of large scale shell-model (LSSM) calculations for the region beyond 132Sn, indicating the behavior of collectivity for the three valence-proton iodine chain with N = 82, 84, 86.

HAEFNER G.;  LOZEVA R.;  NAIDJA H.;  LEBOIS M.;  JOVANCEVIC N.;  THISSE D.;  ETASSE D.;  CANAVAN Rhiann;  RUDIGIER Matthias;  WILSON J. N.;  ADAMSKA E.;  ADSLEY P.;  ALGORA A.;  BABO M.;  BELVEDERE K.;  BENITO J.;  BENZONI G.;  BLAZHEV A.;  BOSO A.;  BOTTONI S.;  BUNCE M.;  CHAKMA R.;  CIEPLICKA-ORYNCZAK N.;  COLLINS S. M.;  CORTES M. L.;  DAVIES P.;  DELAFOSSE C.;  FALLOT M.;  FRAILE L.M.;  GERST R.B.;  GJESTVANG D.;  GUADILLA V.;  HAUSCHILD K.;  HENRICH C.;  HOMM I.;  IBRAHIM F.;  ISKRA L.W.;  JAZWARI S.;  KORGUL A.;  KOSEOGLOU P.;  KROELL T.;  KURTUKIAN-NIETO T.;  LE MEUR L.;  LEONI S.;  LJUNGVALL J.;  LOPEZ-MARTENS A.;  MATHIEU L.;  MIERNIK K.;  NEMER J.;  OBERSTEDT Stephan;  PAULSEN W.;  PIERSA M.;  POPOVITCH Y.;  PORZIO C.;  QI Liqiang;  RALET D.;  REGAN P. H;  REYGADAS-TELLO D.;  REZYNKINA K.;  SANCHEZ-TEMBLEQUE V.;  SCHMITT C.;  SÖDERSTRÖM P.A.;  SUERDER C.;  TOCABENS G.;  VEDIA V.;  VERNEY D.;  WARR N.;  WASILEWSKA B.;  WIEDERHOLD J.;  YAVACHOVA M.;  ZEISER F.;  ZILIANI S.; 

2021-09-02

AMER PHYSICAL SOC

JRC124303

2469-9985 (online),   

https://journals.aps.org/prc/abstract/10.1103/PhysRevC.104.014316,    https://publications.jrc.ec.europa.eu/repository/handle/JRC124303,   

10.1103/PhysRevC.104.014316 (online),