Geonium "K" experiment using spin dependency of cyclotron frequency supports g data of earlier geonium "S" work.

By substituting the relativistic spin state dependence of the cyclotron frequency for the continuous Stern-Gerlach effect and running the geonium atom as a microsynchrocyclotron accelerator we have detected spin flips of the individual trapped electron. In our initial efforts we have been able to obtain a simple symmetric spin resonance about 4-fold narrower instead of a complex asymmetric one and also to support but not as yet seriously test the result of the earlier geonium "S" work, g/2 = 1. 001 159 652 185 5(40).