MEASUREMENTS OF THE GROUND-STATE LAMB SHIFT AND ELECTRON-CORRELATION EFFECTS IN HYDROGENLIKE AND HELIUM-LIKE URANIUM

We report measurements of transition energies for highly ionized urani um. For hydrogenic uranium we have measured 102 130+/-92 eV for the 2p 3/2-1s1/2 transition. This measurement is sensitive to the 1s Lamb shi ft, probing the electron self-energy in high-field QED. In addition, w e have measured the (1s2p)1P1, 3P2-(1s2)1S0 transition in heliumlike u ranium as 100 598+/-111 eV, probing relativistic electron-electron cor relation effects. Both measurements were obtained with a Doppler spect rometer, a proven technique which we have adapted to the field of high -Z precision atomic transition-energy measurements. These measurements demonstrate the potential of this technique to attain approximately 1 eV uncertainties.