Identification of μs isomers in the fission products of241Pu(nth,f)

Penning-trap-assisted study of excitations in Br88 populated in β decay of Se88Czerwiński1, Sieja2, Rza̧ca‐Urban3 et al. 2017Phys. Rev. C74102View full textAdd to dashboardCite

“…This value compared to theoretical values of 4. Interestingly, we could also observe the 111.0-keV line (clearly resolved in the singles spectrum from the 113.9-keV line) corresponding to the decay of the 5.1 μs isomer at 270.0 keV in 88 Br [15]. The half-life obtained from fitting the corresponding time-decay spectrum of the 111.3-keV line is 5.1(9) μs.…”

“…As observed before in Refs. [2,15] the 272.8-keV level decays exclusively to the 158.9-keV level by the 113.9-keV transition, seen in Fig. 5(a) as a pronounced line.…”

“…The total conversion coefficient for the 158.9-keV line was derived from the K-conversion coefficient measured in Ref. [15]. Taking the ratio 0.315, the total intensity of the 775.2-keV line, (I A ) Br = (I A ) 775.2 = 0.625 as reported in [17], and the (I R ) Se calculated using our new excitation scheme of 88 Br, we determined the ground-state feeding of 88 Br to be 26(9)%.…”

Recent Results and Future Prospects for Nuclear Structure Studies at the ILL

“…Using a narrow time window, and mass selection, allows isomeric decays to be observed in very weakly produced fission fragments. Indeed the first observation of excited states in several very neutron-rich nuclei has recently been performed at Lohengrin [1,2].…”

“…The pressure of the gas in the chamber is adjusted so that the fission fragments stop in the last 1 or 2 µm of the mylar foil. A Si(Li) conversion-electron detector, 6 x 2 cm 2 in area, is placed close behind the mylar foil, giving an efficiency of ∼25 %, as described in [2]. Germanium detectors are then placed perpendicular to the beam, in approximately the same geometry as the gamma-ray spectroscopy setup.…”