Ponente
Descripción
31Ar and 33Ar isotopes are very exotic nuclei near the proton drip-line, with high Q-value and low proton separation energy. Therefore, P-delayed protons are emitted in the decay of these nuclei [1,2]. The aim of the IS577 experiment performed at the ISOLDE Decay Station (IDS) [3] was to provide important information on the resonances of 30S, 29P, 31Cl, 33Cl, populated in the beta decay of 31Ar and 33Ar, respectively, as well as to study the study of the mechanism of multiple emission of protons in 31Ar.
The set-up used consisted of 5 Double Sided Si Strip Detectors (DSSD) backed by unsegmented Si-pad detectors in DeltaE-E telescope configuration. This Si-array is located inside the new MAGISOL Si-Plugin Chamber, installed at the new permanent station IDS (ISOLDE-CERN), devoted to beta-decay measurements. In addition, there are 4 HPGe clover-detectors surrounding the chamber for gamma detection. This set-up is very compact with both high efficiency (47% of 4pi) and good energy resolution (25 keV) for multi-particle emission, needed to characterize the different p-channels of 31Ar.
New results will be presented here, such as the observation of new proton transitions and the identification of new excited states of 31Cl and 33Cl with their corresponding spin assignments. Furthermore, we have experimentally determined for the first time the partial width of protons and gammas in the states of 30S located just above the proton separation energy, relevant for the astrophysical rp-process [4]. Our experimental determination of the values of partial widths can reduce the uncertainty in the values of the reaction rate of the 29P(p,g)30S reaction, present in certain stellar environments such as classical novae.
[1] Proposal to the ISOLDE and Neutron ToF Committee, INTC-P-386, September 2013
[2] Physical Review C, 81(2), 024311, 2010
[3] http://isolde-ids.web.cern.ch/isolde-ids/
[4] G.T. Koldste et al. Phys. Letters B 737 (2014) 383-387.
