Abstract
Isomeric yield ratios for the odd- isotopes of and from 25-MeV proton-induced fission on natural uranium have been measured at the JYFLTRAP double Penning trap, by employing the phase-imaging ion-cyclotron-resonance technique. With the significantly improved mass resolution of this novel method isomeric states separated by 140 keV from the ground state, and with half-lives of the order of 500 ms, could be resolved. This opens the door for obtaining new information on low-lying isomers, which are important for nuclear structure, fission, and astrophysics. In the present work the experimental isomeric yield ratios are used for the estimation of the root-mean-square angular momentum of the primary fragments. The results show a dependency on the number of unpaired protons and neutrons, where the odd- In isotopes carry larger angular momenta. The deduced values of display a linear relationship when compared with the electric quadrupole moments of the fission products.
- Received 12 November 2018
- Revised 4 December 2018
DOI:https://doi.org/10.1103/PhysRevC.99.014617
©2019 American Physical Society