Alpha-gamma coincidence spectroscopy of ^259Rf using a mixed Cf target
Abstract
Gamma rays following the α decay of ^259Rf have been observed for the first time by means of α-γ coincidence spectroscopy. ^259Rf was produced via the ^ 251Cf(^12C,4n)^259Rf reaction at the JAEA tandem accelerator. The target consists of 63% ^249Cf, 12% ^ 250Cf, and 25% ^251Cf with a thickness of 420 μg/cm^2. Reaction products were transported with a He/KCl aerosol jet into a rotating wheel α-γ detection system equipped with two sets of two Si detectors and two Ge detectors. Two γ lines were observed at 97.3 and 146.7 keV in coincidence with the 8770 keV α transition of ^259Rf. In addition, a few γ events appeared at ∼125 keV. The energy differences and intensities of these γ transitions, which are very similar to those in the α decay of ^257No, allow us to assign the 3/2^+ [622] configuration to the 146.7 keV level in ^255No as well as to the ground state of ^259Rf. This result indicates that the order of neutron orbitals should be inverted between ^255Fm and ^257No in N=155 isotones.
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- October 2009
- Bibcode:
- 2009APS..HAW.EH011A