Abstract :
An accurate sensitive technique for experimentally determining the electricfield distribution and space-charge density within a magnetron has been developed by Dr. D. L. Reverdin at the National Bureau of Standards in Washington, D. C. The new method, which is also well suited to investigations of electron-optical lenses, gas discharge, and other space-charge problems, is a modification of the electron-optical shadow technique recently developed at the Bureau for the quantitative study of minute electric and magnetic fields. A magnetic lens is used to produce shadow images of two fine-wire screens placed at either end of the magnetron in the path of an electron beam. Then, from the distortion in the shadow network caused by deflection of the electron rays as they pass through the magnetron field, the radial electric field is computed. These results are used to obtain the space-charge distribution.
