Dr. Livius Trache, Astrofizica nucleara cu nuclee exotice si fascicule radioactive (II) Spectroscopie prin dezintegrari.

Thursday 28 Mar 2013, 11:00 → 12:00 Europe/Bucharest

I will continue the review of indirect methods in nuclear astrophysics using exotic nuclei and radioactive nuclear beams, review started some weeks ago. The decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. It aims at characterizing states that are resonances in reactions important in nucleosynthesis. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. Short-lived radioactive species were produced in-flight and separated using the MARS spectrometer of TAMU, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. Gamma ray were measured in parallel. We have studied the decay of 23Al, 27P, 31Cl relevant for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. More recently we have radically improved the technique using a gas based detector we call AstroBox.