Electron beam fluorescence system to measure gas density in impulse facilitiesVery rapid measurements, ranging from a few microsecond to milliseconds in duration, characterize studies made in shock regions or behind them. A system to measure gas density under such conditions in a 15.24-cm (6-in.) expansion tube is described. The basic elements are an electron beam of moderate energy and high current capability, an optical detector, and the associated electronics and data readout equipment. A heated-cathode electron gun, capable of pulsed operation and delivering up to 200 milliamperes current, provides the source of electrons. Optics include a simple collector lens, aperture, collimator lens, filters, and a photomultiplier tube. The photomultiplier output signal was recorded by means of photographed oscilloscope traces for pulsed beam operation.
Document ID
19740056464
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Hoppe, J. C. (NASA Langley Research Center Instrument Research Div., Hampton, Va., United States)