0000000000663176
AUTHOR
David H M
Decay and Fission Hindrance of Two- and Four-Quasiparticle K Isomers in 254Rf
International audience; Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and 247(73) mu s have been discovered in the heavy (254)Rf nucleus. The observation of the shorter-lived isomer was made possible by a novel application of a digital data acquisition system. The isomers were interpreted as the K-pi = 8(-), nu(2)(7/2(+)[624]; 9/2(-)[734]) two-quasineutron and the K-pi = 16(+), 8(-)nu(2)(7/2(+)[624]; 9/2(-)[734] circle times 8(-)pi(2) (7/2(-)[514]; 9/2(+)[624]) four-quasiparticle configurations, respectively. Surprisingly, the lifetime of the two-quasiparticle isomer is more than 4 orders of magnitude shorter than what has been observed for analogous isomer…
Superallowed α Decay to Doubly Magic 100Sn
We report the first observation of the 108Xe→104Te→100Sn α-decay chain. The α emitters, 108Xe [Eα=4.4(2) MeV, T1/2=58+106−23 μs] and 104Te [Eα=4.9(2) MeV, T1/2<18 ns], decaying into doubly magic 100Sn were produced using a fusion-evaporation reaction 54Fe(58Ni,4n)108Xe, and identified with a recoil mass separator and an implantation-decay correlation technique. This is the first time α radioactivity has been observed to a heavy self-conjugate nucleus. A previous benchmark for study of this fundamental decay mode has been the decay of 212Po into doubly magic 208Pb. Enhanced proton-neutron interactions in the N=Z parent nuclei may result in superallowed α decays with reduced α-decay wi…