Theory of the Hydrogen Maser

The behavior of the atomic hydrogen maser is analyzed for both stationary and transient operation. An expression for noise in the signal from the maser oscillator is derived by applying the previously developed theory of Shimoda, Wang, and Townes. A variety of relaxation phenomena are analyzed, including effects of chemical reaction with the surface and magnetic field inhomogeneities. Several mechanisms leading to frequency shifts in the maser are also analyzed, including cavity pulling and the Doppler effect.