Beta-delayed proton emission of the drip-line nucleus 73Rb

Not scheduled
15m
Kunibiki Messe (Matsue)

Kunibiki Messe

Matsue

Poster Contribution

Speaker

Prof. Andrew Rogers (Department of Physics and Applied Physics, University of Massachusetts Lowell)

Description

Nuclei near the neutron and proton drip lines play a key role in our understanding of astrophysics, weak-interaction physics, and nuclear structure. Weakly-bound or proton-unbound nuclei at the rp-process waiting points, such as the unbound Tz = −1/2 nucleus 73Rb, are critical for constraining calculations and observations of type I x-ray bursts. For instance, the rp process is greatly slowed near 72Kr (N = Z) due to its relatively long β-decay half-life and inhibited proton capture. This waiting point, however, may be bypassed by sequential 2p-capture through 73Rb - a reaction which is sensitive to the 73Rb proton separation energy [1]. The recent discovery of the relatively long-lived 72Rb nuclear "sandbank" highlights the interplay of the Coulomb interaction and structure effects that can arise at the proton drip line, particularly in the region of 73Rb [2]. To probe the extent by which 73Rb is proton unbound we have performed an implant-decay experiment designed to measure β-delayed protons from states in 73Rb fed through the decay of 73Sr (t1/2 ~ 30 ms). The experiment was carried out at NSCL where a newly available 92Mo primary beam was used to access neutron-deficient nuclei with Z>36 (krypton), producing 73Sr as well as other nearby neutron-deficient isotopes of interest. Short-lived nuclei were transported to the Beta-Counting Station (BCS) where they were identified and implanted in a silicon DSSD surrounded by the Segmented Germanium Array (SeGA). The secondary beam was purified with the RF Fragment Separator which reduced the total implantation rate to ~10 pps, thereby enabling the successful detection and correlation of β-delayed proton groups from 73Rb. Details of the experimental setup and new decay results, as well as the potential impact on the 72Kr rp-process waiting point will be presented.

  • This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-FG02-94ER40848 (UML) and DE-AC02-06CH11357 (ANL); the National Nuclear Security Administration through the Nuclear Science and Security Consortium under Award Number(s) DE-NA0003180 and/or DE-NA0000979; and the National Science Foundation under Contract No. PHY-1102511.

Primary authors

Prof. Andrew Rogers (Department of Physics and Applied Physics, University of Massachusetts Lowell) Dr Christopher Morse (Department of Physics and Applied Physics, University of Massachusetts Lowell)

Co-authors

Dr Alexander Dombos (National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University) Prof. Christopher Lister (Department of Physics and Applied Physics, University of Massachusetts Lowell) Douglas Soltesz (Institute of Nuclear and Particle Physics, Department of Physics and Astronomy) Emery Doucet (Department of Physics and Applied Physics, University of Massachusetts Lowell) Prof. Hendrick Schatz (National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University) Dr Jason Clark (Argonne National Laboratory) Katherine Childers (National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University) Dr Konrad Schmidt (National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University) Kristyn Brandenburg (Institute of Nuclear and Particle Physics, Department of Physics and Astronomy) Prof. Peter Bender (Department of Physics and Applied Physics, University of Massachusetts Lowell) Rebecca Lewis (National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University) Prof. Sean Liddick (National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University) Dr ShiLun Jin (National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University) Shiv Kumar Subedi (Institute of Nuclear and Particle Physics, Department of Physics and Astronomy) Prof. Zachary Meisel (Institute of Nuclear and Particle Physics, Department of Physics and Astronomy)

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