Speaker
Description
In the beta decay of exotic nuclei, far from stability, the daughter nuclei might be formed in an excited state, which is unstable against particle emission. This phenomenon is called β-delayed particle emission and is due to a high Q-value and low separation energy for particle emission. The decay of the proton drip-line nucleus $^{31}$Ar is one of the most exotic β-delayed multi-particle decays. It has a large $Q_{β}$-window and as a consequence many different β-delayed decay channels are open: βγ, βp, βpγ, β2p, β2pγ, β3p and perhaps also β3pγ [1].
The aim of the IS577 experiment performed at the ISOLDE Decay Station (IDS) was the identification of the β3p and β3pγ-decays in $^{31}$Ar as well as to provide important information on the resonances of $^{30}$S and $^{29}$P, relevant for the astrophysical rp-process [2].
The IDS is a new installation at ISOLDE devoted to β-decay measurements. This is the first time that one of these kind of experiments based on decay studies is carried out taking advantage of this permanent station. Our collaboration installed a new implantation chamber; the MAGISOL Si-Plugin Chamber, consisting in 5 Double Sided Si Strip Detectors (DSSSD) backed by un-segmented Si-pad detectors in ΔE-E telescope configuration. In addition, there are 4 HPGe clover-detectors surrounding the chamber for gamma detection. This setup is compact with high efficiency for both multi-particle emission and gamma ray detection with low cutoff energy as well.The Si-array detects multi proton emission over a wide energy range with the good energy (25 KeV) and angular ($3^{o}$) resolution that are needed to characterize the different p-channels of $^{31}$Ar. Further, with this setup it is possible to measure proton-gamma and proton-proton coincidences, therefore, we can see gamma transitions from levels of $^{30}$S and $^{29}$P and determine the spin of levels of $^{30}$S and $^{31}$Cl, respectively. I will present here preliminary results, as one-proton-gated gamma spectrum and proton-proton angular correlations. [1] Proposal to the ISOLDE and Neutron ToF Committee, INTC-P-386, September 2013 [2] G.T. Koldste et al. Phys. Letters B 737 (2014) 383-387.
