First Nuclear Physics publication in PRX

March 2014

The CRIS Collaboration publishes the first ever Nuclear Physics article in Physical Review X, the new online open-access journal from the APS.

Following a successful experimental campaign in 2012, the CRIS Collaboration has recently published the first ever Nuclear Physics article in Physical Review X, the new online open-access journal from the APS.

The Collinear Resonance Ionisation Spectroscopy (CRIS) technique combines the high-resolution of collinear laser spectroscopy, in which the Nuclear Physics Group is a world leader, with the high sensitivity and selectivity of resonance ionisation. The radioactive beams produced at CERN ISOLDE are delivered to the CRIS experiment as a cocktail of different isobars. Using atomic transitions finely tuned for a single element, it is possible to resonantly excite an electron beyond the ionisation threshold and produce an ion. The resolution of the technique is sufficient to identify the hyperfine structure of the atomic transitions and the frequency shift between different isotopes, from which nuclear observables such as spin, electromagnetic moments and changes in charge radii can be extracted.

The strength of the CRIS experiment that has warranted the publication in PRX is the combination of this technique with an integrated nuclear spectroscopy setup, with which the alpha decay of the re-ionised isotopes, and sometimes isomers, can be performed. Using the CRIS technique, 3 states of 204Fr and 2 of 202Fr were successfully separated and the different hyperfine components were tagged according to the characteristic decay patterns of each isomer. This offered an unprecedented accuracy in the study of those isotopes and the first measurement of the branching ratios in the decay of the (10-) isomer in 204Fr.

More information can be found in the article and in the synopsis written by G. Sprouse.