Investigation of the missing isomer in the rare-earth nucleus <sup>158</sup>Pm
ORAL
Abstract
Neutron-rich nuclei in the rare-earth region are important for understanding the effects of nuclear structure evolution and play a role in nuclear astrophysics. An enhanced rare-earth peak in the solar abundance pattern is also not fully understood, yet its formation may reveal information about possible astrophysical conditions. The odd-odd nucleus 158Pm is particularly interesting as a predicted isomeric state has yet to be clearly established. A β-decay experiment was performed at ANL using the HPGe clover detectors of the X-Array combined with the SATURN decay station. Radioactive ions produced by the CARIBU facility were isobarically separated and delivered to the experimental setup. The tape system was optimized to focus on the decay of 158Pm. It was discovered that the origin of the previously assigned 121-keV isomeric γ-ray transition in 158Pm originates instead from the decay of 158Nd. These observations provide the first high-resolution spectroscopic decay data in 158Pm, extending our knowledge further into more neutron-rich systems.
*This work is supported by DE-FG02-94ER40848(UML), DEAC02-06CH11357 (ANL), DE-SC0021315(LSU), DE-AC02-98CH10886 (BNL) and DE-AC52-07NA27344 (LLNL).
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Presenters
Sanjanee W Waniganeththi
University of Massachusetts Lowell
Brookhaven National Laboratory
Authors
Sanjanee W Waniganeththi
University of Massachusetts Lowell
Brookhaven National Laboratory
Andrew M Rogers
University of Massachusetts Lowell
University of Massachusetts-Lowell
Filip G Kondev
Argonne National Laboratory
Physics Division, Argonne National Laboratory, Lemont, IL 60439, USA
