Apparatus for study of energy parameters of gas-dynamic molecular beams

The authors describe a three-chamber source of gas-dynamic molecular beams with oilless evacuation of the second and third stages that generates a beam with an angular divergence of 1 degree 30' and a density 3.5·1011 molecules/cm3 as well as an experimental procedure for determination of beam parameters. The velocity-distribution function for the molecules in a nitrogen molecular beam is reconstructed by time-of-flight spectroscopy of the metastable molecules excited by an electron beam. Results of determination of the mean mass velocity, static temperature, and velocity ratio of a nitrogen molecular beam are given. Also described is an optical system that permits real-time monitoring of beam density during time-of-flight experiments