Mon·Jul 13, 2015Monday·July 13, 2015

1. 01*

   Gamma ray production cross sections in proton induced reactions on natural Mg, Si and Fe targets over the proton energy range 30 up to 66 MeV

   W. Yahia-Chérif · S. Ouichaoui · J. Kiener🇫🇷 · V. Tatischeff🇫🇷 · E. Lawrie🇿🇦 · J.J. Lawrie🇿🇦 · A. Belhout · H. Benhabiles · T.D. Bucher🇿🇦 · A. Chafa · S. Damache · M. Debabi and 20 other authors

   Gamma-ray excitation functions have been measured for 30, 42, 54 and 66 MeV proton beams accelerated onto C + O (Mylar), Mg, Si, and Fe targets of astrophysical interest at the separate-sector cyclotron of iThemba LABS in Somerset West (Cape Town, South Africa). A large solid angle, high energy resolution detection system of the Eurogam type was used to record Gamma-ray energy spectra. Derived preliminary results of Gamma-ray line production cross sections for the Mg, Si and Fe target nuclei are reported and discussed. The current cross section data for known, intense Gamma-ray lines from these nuclei consistently extend to higher proton energies previous experimental data measured up to Ep ~ 25 MeV at the Orsay and Washington tandem accelerators. Data for new Gamma-ray lines observed for the first time in this work are also reported.

   nucl-ex0 citations
2. 02*

   First Measurement of the ${}^{96}$Ru(p,$\gamma$)${}^{97}$Rh Cross Section for the p-Process with a Storage Ring

   Bo Mei🇨🇳 · Thomas Aumann🇩🇪 · Shawn Bishop🇯🇵 · Klaus Blaum🇩🇪 · Konstanze Boretzky🇩🇪 · Fritz Bosch · Carsten Brandau🇩🇪 · Harald Bräuning · Thomas Davinson🇬🇧 · Iris Dillmann🇩🇪 · Christina Dimopoulou · Olga Ershova🇩🇪 and 35 other authors

   This work presents a direct measurement of the ${}^{96}$Ru($p,\gamma$)${}^{97}$Rh cross section via a novel technique using a storage ring, which opens opportunities for reaction measurements on unstable nuclei. A proof-of-principle experiment was performed at the storage ring ESR at GSI in Darmstadt, where circulating ${}^{96}$Ru ions interacted repeatedly with a hydrogen target. The ${}^{96}$Ru($p,\gamma$)${}^{97}$Rh cross section between 9 and 11 MeV has been determined using two independent normalization methods. As key ingredients in Hauser-Feshbach calculations, the $\gamma$-ray strength function as well as the level density model can be pinned down with the measured ($p,\gamma$) cross section. Furthermore, the proton optical potential can be optimized after the uncertainties from the $\gamma$-ray strength function and the level density have been removed. As a result, a constrained ${}^{96}$Ru($p,\gamma$)${}^{97}$Rh reaction rate over a wide temperature range is recommended for $p$-process network calculations.

   nucl-exastro-ph.IMPRC(2015)·59 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.