On-Line Nuclear Orientation

Some dilution refrigerators are designed to be placed on-line to a radioactive beam. Nuclei are implanted into the host lattice which is already at mK temperature. The nuclei will then relax (reach thermal equilibrium), taking a characteristic time, tSLR. Provided that tSLR > T1/2, then the nuclei will orient before decaying so experiments are possible.

The group has access to beams of both proton- and neutron-rich isotopes, allowing studies on both sides of the valley of stability. At CERN we can orient the proton-rich products of spallation reactions of a 1 GeV proton beam on various targets, in the NICOLE refrigerator.

Neutron-rich fission products are studied using the OSIRIS separator in Studsvik, Sweden. In 1995 the group moved the refrigerator from the NSF in Daresbury to there, as part of a successful collaboration with Prof. B. Fogelberg of Uppsala University. Experiments in Studsvik have produced measurements of numerous magnetic moments around the doubly magic 132Sn.