Probing Single Helium Atoms in a Magneto-Optical Trap and the Nuclear Charge Radii of ⁶He and ⁸He
Dr. Peter Müller (Argonne National Lab, Chicago)

The short-lived isotopes ⁶He (t_1/2 = 807 ms) and ⁸He (t_1/2 = 119 ms) exhibit a loosely bound neutron halo around a ⁴He like core. Nuclear charge radii measurements of these exotic isotopes probe the interaction between the halo-neutrons and the core and provide tests for theoretical calculations of nuclear structure. The difference of charge radii between isotopes can be extracted from high-resolution measurements of atomic isotope shifts. In this talk I will present a new technique for measuring isotope shifts in helium based on laser spectroscopy of single atoms in a magneto-optical trap. First results for the charge radius of ⁶He produced on-line at the Argonne ATLAS accelerator will be shown and prospects for measuring ⁸He will be discussed.