Measuring the Density of a Molecular Cluster Injector via Visible Emission from an Electron Beam
Authors: D.P. Lundberg, R. Kaita, R. Majeski, and D.P. Stotler
Abstract:
A method to measure the density distribution of a dense hydrogen gas jet is pre- sented. A Mach 5.5 nozzle is cooled to 80K to form a flow capable of molecular cluster formation. A 250V, 10mA electron beam collides with the jet and produces Hα emission that is viewed by a fast camera. The high density of the jet, several 1016cm−3, results in substantial electron depletion, which attenuates the Hα emission. The attenuated emission measurement, combined with a simplified electron-molecule collision model, allows us to determine the molecular density profile via a simple iterative calculation.
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Submitted to: Review of Scientific Instruments (June 2010)
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Download PPPL-4530 (pdf 184 KB 10 pp)
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