High Sensitivity Laser Spectroscopy with Atoms from a Cooled Helium Jet

We have developed a cryogenic He-jet system which efficiently transports radioactive atoms produced on-line at the Argonne National Lab Tandem-Linac Accelerator away from the production region and forms them into a cool atomic beam. This atomic beam will be probed with high sensitivity laser spectroscopy using the photon burst method. The ultimate goal of this work is to determine the sizes, shapes, and magnetic moments of short-lived nuclei through their atomic hyperfine structure. Preliminary measurements with the He-jet system and the adaption of the photon burst method to this new geometry are described.