Mylar electron beam windows

Thin sheets of Mylar have been found a useful material for electron beam windows for beams in the 0.5- to 1.0- Mev energy range. The material finds special application in beam excited plasma devices where the plasma and the electron gun are to be held at different pressures. Experiments are described in which the amount of beam scatter and beam debunching caused by the Mylar are determined. Data is presented on the damage to the Mylar caused by the electron beam and the resultant decrease in pressure differential that the bombarded Mylar can withstand. The experiments were also conducted using Mylar sheets coated with 4000-5000 A coatings of aluminum.