CRIS: Studying the neutron deficient francium isotopes with laser and decay spectroscopy

by Kara Marie Lynch (University of Manchester (GB))

Thursday 28 Feb 2013, 14:30 → 15:30 Europe/Zurich

26-1-022 (CERN)

The Collinear Resonant Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN uses laser radiation to stepwise excite and ionize an atomic beam for the purpose of ultra-sensitive detection of rare isotopes, and hyperfine structure measurements. The technique also offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new program using the CRIS technique to select only nuclear isomeric states for decay spectroscopy commenced in 2011. The isomeric ion beam is selected using a resonance of its hyperfine structure, where it is deflected to a decay spectroscopy station (DSS). This consists of a rotating wheel implantation system for alpha and beta decay spectroscopy, and up to three germanium detectors around the implantation site for gamma-ray detection. Laser spectroscopy provides a measurement of the spin of the ground and isomeric states in the parent nucleus, while the level structure of the daughter nucleus comes from the complementary decay spectroscopy, thus providing a wealth of information on the isotope under investigation. Resonant ionization laser spectroscopy and the new technique of laser assisted decay spectroscopy have recently been performed at the CRIS beam line on the neutron-deficient francium isotopes. Here the latest results from our experimental campaign will be presented, alongside an overview of the CRIS beam line and the DSS.