Search for parity non-conservation in the hydrogen atom

A search for parity non-conservation was made in the hydrogen atom by looking for a small admixture of the 2P/sub 1/2/ state in the 2S/sub 1/2/ state. Since the predicted effect due to neutral current interaction is exceedingly small an interference technique was used. The two 2S/sub 1/2/(m;sub J/ = 1/2) → 2S/sub 1/2/(m/sub J/ = -1/2) parity conserving and parity non-conserving amplitudes were driven in two separate microwave cavities. A cylindrical geometry is chosen for the apparatus for a great reduction of the contributions from spurious amplitudes. The difference in the transition rate, when the relative sign of the two amplitudes are changed, is the PNC signal. The apparatus, control system and the different measurement techniques are discussed. The present results are limited by the systematic errors due to the presence of stray electric fields. The observed asymmetry when expressed in terms of C2/sub p/ was found to be equal to 430 +- 500. Possible modifications for further improvement and the feasibility of an experiment in zero magnetic field is discussed in the context of future use of a thermal beam