Separated Oscillatory Field Microwave Measurement of the n=2 Triplet P Fine-Structure of Helium

The Ramsey method of separated oscillatory fields is being used to make a very precise microwave measurement of the n=2 triplet P J=1-to-J=2 interval in helium. The excellent signal-to-noise obtained in these measurements allows for extensive studies of possible systematic effects. Comparison between precise measurements of the n=2 triplet P fine structure and theoretical predictions will allow for a precise determination of the fine-structure constant when the current large discrepancy between experiment (PRL \underline {95} 203001; PRL \underline {87} 173002; PRL \underline {84} 4321; Can J Phys \underline {83} 301) and theory (PRL \underline {97} 013002; Can J Phys \underline {80} 1195) is resolved.