Electron-time Of-flight Spectrometer
نویسنده
چکیده
A velocity selector is described which is designed for measurement of the total collision cross section of electrons in the energy region below one volt. The system determines the distributions of times of flight of single electrons over a measured path at selected pressures of a specimen gas. The electrons are generated by repetitive illumination of a photo-emitter by a spark gap, pass over a shielded drift path, enter an accelerating field, and impinge on an electron multiplier. Electronic equipment and data reduction for analysis of time-of-flight and amplitude distributions of electron counts are described; data illustrative of performance are presented, including typical transmission measurements in helium and argon which extend to 100 millivolts. Applications and extensions of the technique are discussed.
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