Focusing Molecular Beams of NH3

Abstract

The problem of forming molecular beams for use in ammonia masers is examined. It is shown theoretically and experimentally that through the use of a new type of parabolic focuser with a ``point source'' effuser, the molecular flow may either be reduced by a factor of 8, for the same power output, or the power output may be increased by a factor of 2 for the same molecular flow. A theory of beam formation in a multitube effuser is described. This shows that the most intense molecular beam is formed by an effuser of small overall diameter. Design considerations are discussed for parabolic, upper‐state focusers, and for coaxial, lower‐state focusers. The operation of a system is described, using a lower‐state focuser and an ionization detector, in which lower‐state molecules produced by maser oscillation may be detected.