Abstract
Mass measurements of , , and performed at the LEBIT facility at the NSCL by Penning trap mass spectrometry are presented. The rare isotopes were produced by fast beam fragmentation and in-flight separation, then converted to a low energy beam using a gas stopping technique. Masses of the nuclei and have been determined with uncertainties of and , respectively, representing a more than ten-fold improvement in precision over previous measurements. For , , , and relative mass uncertainties of were obtained. is found to be 135 keV more bound than the value listed in the 2003 Atomic Mass Evaluation. Using theoretical Coulomb shift energies in combination with the experimental mass values for , , and , masses for , , and are predicted with an estimated uncertainty of 100 keV. These mass values, in conjunction with our measurements, were used to calculate improved effective lifetimes of the rp-process waiting point nuclei and . We find that is less of a waiting point while poses a larger delay in the rp-process than previously thought. The improved mass values in this region were also used to investigate the neutron-proton pairing energy of odd-odd nuclei.
- Received 24 January 2007
DOI:https://doi.org/10.1103/PhysRevC.75.055801
©2007 American Physical Society