High spin isomers in129Snand130Sb

New sub-μs isomers in125,127,129Snand isomer systematics ofLozeva1, Simpson2, Grawe3 et al. 2008Phys. Rev. CSelf Cite

“…[12,36] are confirmed here, though the low-energy decays of the 3.6(2) µs 19/2 + isomer (19.7 keV) and the 2.4(2) µs 23/2 + isomer (41.0 keV) were not observed. A BG-subtracted energy spectrum from the end of the time range (as for 125 Sn and 127 Sn) is presented in Fig.…”

“…The (23/2 + ) state has already been observed as an isomer in the neighboring 123,127,129 Sn nuclei [2,12,36]. Two previous experiments [1,10] studying 125 Sn at intermediate spin were unable to observe the (23/2 + ) isomer due to poor particle identification and a lack of statistics, respectively.…”

“…Further away from stability, Sn nuclei and their vicinity have been studied by using relativistic fission [5][6][7] and fragmentation [8,9] reactions. Intermediatespin states were observed either directly after in-flight mass separation of µs isomeric states, produced by thermal neutroninduced fission [10][11][12], or by the β decay of intermediate-spin long-lived (seconds) In isomers [13,14]. The aforementioned experiments have allowed the complete νh −n 11/2 , seniority v = 2 multiplet to be measured for even-mass Sn isotopes in the mass range A = 116-130.…”

“…These isomers, however, were not observed in the more neutron-rich Sn isotopes using fission reactions, as β decay cannot populate such high-spin states and their predicted lifetime of ∼200 ns is below the observational limit of the Lohengrin mass spectrometer at the ILL, where the flight time is around 2 µs [10]. Valuable information about intermediate-spin states in the heavy odd Sn nuclei was however obtained from the decay of νh −2 11/2 d −1 3/2 µs isomeric states [10][11][12]. In order to complete the systematic data for the νh −n 11/2 , v = 3 isomers, to see whether their B(E2) values fit into the trend of the v = 2 isomers, and to gain more information on intermediate-spin states in these nuclei, data from a recent experimental campaign using relativistic fission or fragmentation performed at the fragment separator (FRS) at GSI [17] were examined, where the flight time of the reaction products was around 300 ns.…”

“…A good description of the experimental data is found from using an effective neutron charge of e n = 0.70e, in agreement with previous work in this region [19,20], and at variance with the larger values found in Refs. [3,12,21]. The experimental method and results are introduced in Secs.…”