B-delayed charged particle decays of neutron-deficient nuclei 20Mg and 22,23Si

by Dr Mathieu Babo (Grand Accelerateur National d’Ions Lourds (GANIL))

Monday 3 Oct 2016, 11:00 → 12:00 Europe/Rome

LAE meeting room (INFN-LNL)

A novel arrangement of three double-sided Si strip detectors (DSSSD) surrounded by 16 HPGe detectors was employed at NSCL (MSU, USA) to study the -delayed charged particle decays of the neutron-deficient Si isotopes 22;23Si. These nuclei are situated at or near the proton drip-line, and can decay by several exotic -delayed decay paths. Depending on the mass predictions, 22Si is a possible candidate for the recently discovered 2-proton radioactivity.
The well-known p emitter 20Mg was also studied, and the spectroscopy provided in this work was compared to previous measurements to assess the accuracy of the method. The decay scheme was built using -ray gated proton spectra and compared to previous measurement.
Detailed decay spectroscopy, including the measurements of the excitation energies for the isobaric analog states (IAS) in the 22;23Al daughters, was performed and compared to previous measurements and USDB shell model calculations. New exotic decay pathways, such as 3p and 2p were tentitavely identified in 23Si and 22Si respectively.
Using the isobaric mass multiplet equation (IMME), the mass of 23Si was deduced. The first indirect measurement of the mass of the lightest TZ = 􀀀3 nucleus 22Si was obtained using the ft value of the superallowed Fermi decay to the IAS in the daughter 22Al, in order to assess whether its ground state is a candidate for 2p-radioactivity.