2010/08/18 by P. Hosmer, H. Schatz, A. Aprahamian +27
Physics and Astronomy · #Astronomical and nuclear sciences #Atomic and Molecular Physics #Nuclear physics research studies #nucl-ex
paper · pdf · doi:10.1103/physrevc.82.025806
published as Phys.Rev.C82:025806,2010 · 13 pages, 13 figures
openalex publication_date 2010/08/18 · arxiv created 2010/11/23 · arxiv updated 2010/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The \ensuremathβ decays of very neutron-rich nuclides in the Co--Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL \ensuremathβ-counting station in conjunction with the neutron detector NERO. We measured the branchings for \ensuremathβ-delayed neutron emission (Pn values) for 74Co (18\ifmmode±\else\textpm\fi15%) and ^75\ensuremath-77Ni (10\ifmmode±\else\textpm\fi2.8%, 14\ifmmode±\else\textpm\fi3.6%, and 30\ifmmode±\else\textpm\fi24%, respectively) for the first time, and remeasured the Pn values of ^77\ensuremath-79Cu, 79,81Zn, and 82Ga. For ^77\ensuremath-79Cu and for 81Zn we obtain significantly larger Pn values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of 75Co (30\ifmmode±\else\textpm\fi11 ms) and 80Cu (170_\ensuremath-50+110 ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is better able to reproduce the A=78--80 abundance pattern inferred from the solar abundances. The new data also influence r-process models based on the neutrino-driven high-entropy winds in core collapse supernovae.