value in Kr

Rgis, J.-M.*; Jolie, J.*; Saed-Samii, N.*; Warr, N.*; Pfeiffer, M.*; Blanc, A.*; Jentschel, M.*; Kster, U.*; Mutti, P.*; Soldner, T.*; et al.

Physical Review C, 90(6), p.067301_1 - 067301_4, 2014/12

https://doi.org/10.1103/PhysRevC.90.067301

A smooth onset of collectivity in Kr has been determined from reported and E(2) values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the value in Kr, which was produced by cold-neutron-induced fission of U. The lifetime of the 2 state in Kr was measured via the electronic timing technique using the EXILL and FATIMA spectrometers. Based on the measured mean lifetime of = 15(10) ps, the value of 13 W.u. in Kr is determined for the first time and the smooth onset of deformation in the even-even Kr isotopes beyond neutron number N=50 is confirmed.