MICRO-ACCELERATOR TECHNIQUE FOR BETTER GEONIUM DATA

When measuring the g-factor of the electron to obtain information on i ts possible structure, an increase by factor 3 in resolution is about as important an improvement as a 3-fold increase in accelerator energy would be to high energy physicists looking for the Higgs particle. In this paper I review recent published work carried out with my colleag ues at the University of Washington that has yielded a new spectroscop ic technique capable of producing symmetric spin and cyclotron resonan ces only 1.1 Hz and 160 Hz wide, respectively as compared with the las t Seattle geonium ''S'' work in which the resonances were highly asymm etric and the corresponding best widths were 3 Hz and 2000 Hz respecti vely. The new technique relies on the relativistic spin fine structure of the cyclotron resonance and the well known fact that in a synchro- cyclotron the frequency of the rf drive field must be swept down in or der to keep up with the relativistic mass increase. Clearly an acceler ation cycle can only succeed when the process does start at a frequenc y above a threshold value close to the zero energy cyclotron frequency nu(c) to be measured. This threshold frequency then provides a fair a pproximation of nu(c), later calibrated relative to the 0 --> 1 cyclot ron transition.