High-precision mass measurements for the rp-process at JYFLTRAP

University of Jyväskylä, P.O. Box 35 (YFL) FI-40014 University of Jyväskylä, Finland

^* Corresponding author: lacanete@student.jyu.fi

Published online: 30 December 2017

Abstract

The double Penning trap JYFLTRAP at the University of Jyväskylä has been successfully used to achieve high-precision mass measurements of nuclei involved in the rapid proton-capture (rp) process. A precise mass measurement of ³¹Cl is essential to estimate the waiting point condition of ³⁰S in the rp-process occurring in type I x-ray bursts (XRBs). The mass-excess of ³¹C1 measured at JYFLTRAP, -7034.7(3.4) keV, is 15 more precise than the value given in the Atomic Mass Evaluation 2012. The proton separation energy S_p determined from the new mass-excess value confirmed that ³⁰S is a waiting point, with a lower-temperature limit of 0.44 GK. The mass of ⁵²Co effects both ⁵¹Fe(p,γ)⁵²Co and ⁵²Co(p,γ)⁵³Ni reactions. The mass-excess value measured, - 34 331.6(6.6) keV is 30 times more precise than the value given in AME2012. The Q values for the ⁵¹Fe(p,γ)⁵²Co and ⁵²Co(p,γ)⁵³Ni reactions are now known with a high precision, 1418(11) keV and 2588(26) keV respectively. The results show that ⁵²Co is more proton bound and ⁵³Ni less proton bound than what was expected from the extrapolated value.