Electron-Beam Generated Air Plasma: Sensors to Quantify Beam Current and Electron Density

Summary form only given. Sensors to measure the electron beam flux generated by an electron source operating at 100 keV are described. Electrons propagate into an air-plasma test cell through a transmission-window foil. A model for current stopped by the foil is discussed and compared to measurements with sensors within the test cell that is filled with air at a pressure between 1 mtorr and 760 torr. Optical emissions at 337.1 nm originate as a byproduct of electron-beam impact ionization provide an additional sensor. The N₂(C³Pi_u-B³Pi_g) emission detected by an optical fiber is calibrated to the current propagating through the transmission window. The calibrated fiber can then be moved within the test cell to quantify energy deposition. An air chemistry program is used to relate energy deposition to the rate of electron-ion pair production per cm³. The methodology to process data and reduce energy deposition to electron density concentration is detailed.