Hydrogen Spectroscopy with a Lamb-shift Polarimeter - An Alternative   Approach Towards Anti-Hydrogen Spectroscopy Experiments
  A Lamb-shift polarimeter, which has been built for a fast determination of the polarization of protons and deuterons of an atomic-beam source and which is frequently used in the ANKE experiment at COSY-J\"ulich, is shown to be an excellent device for atomic-spectroscopy measurements of metastable hydrogen isotopes. It is demonstrated that magnetic and electric dipole transitions in hydrogen can be measured as a function of the external magnetic field, giving access to the full Breit-Rabi diagram for the $2^2S_{1/2}$ and the $2^2P_{1/2}$ states. This will allow the study of hyperfine structure, $g$ factors and the classical Lamb shift. Although the data are not yet competitive with state-of-the-art measurements, the potential of the method is enormous, including a possible application to anti-hydrogen spectroscopy. 
M.P. Westig, R. Engels, K. Grigoryev, M. Mikirtytchiants, F. Rathmann,   H. Paetz gen. Schieck, G. Schug, A. Vasilyev and H....
physics.atom-ph