Characteristics of the Beam Type Maser I

Velocity distribution of molecules in the beam type maser is considered fairly completely, though the mathematical approach is rather approximate. Because slower molecules spend longer time in the cavity, the effective average velocity of molecules is considerably smaller than the most probable velocity, when the rf power level and the focuser voltage are low. Amplitude vs. focuser voltage and vs. frequency characteristics are obtained, which seem to be in good agreements with experiments. Finally frequency shift due to the unresolved hyperfine structure is discussed and shown to be appreciable (a few parts in 10 8 ).