Abstract: An ion plasma electron gun for the generation of electron beams which exhibits electron beam dose uniformity and which is capable of varying the dose received by a material to be irradiated. Positive ions generated by a wire in a plasma discharge chamber are accelerated through an extraction grid onto a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode, causing the cathode to emit secondary electrons which form an electron beam. After passing through the extraction grid in the plasma discharge chamber, the electron beam exits from the gun by way of a second grid and a foil window supported on the second grid. The gun is constructed so that the electron beam passing through the foil window has a relatively large area and uniform electron distribution which is subsantially the same as the ion distribution of the ion beam impinging upon the cathode.

Abstract: An ion plasma electron gun for the generation of large area electron beams with uniform electron distribution. Positive ions generated by a wire in a plasma discharge chamber are accelerated through an extraction grid into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam. After passage through an extraction grid and plasma discharge chamber, the electron beam exits from the gun by way of a second grid and a foil window supported on the second grid. The gun is constructed so that the electron beam passing through the foil window has a relatively large area and uniform electron distribution which is substantially the same as the ion distribution of the ion beam impinging upon the cathode.

Abstract: An apparatus and method for the phase-transition cooling of particle-transparent windows in charged particle accelerator systems, wherein the apparatus and method permit the operation of the particle-transparent window at a desired temperature by directing an atomized, vaporizable coolant liquid over the window surface, the coolant liquid having a boiling point approximately equal to the desired operating temperature of the window, so that heat is absorbed as the liquid coolant changes from a liquid phase to a gaseous phase.

Abstract: A foil covering for the apertured exit window for a broad beam electron gun is placed in tension by stretching it over a raised edge which extends parallel to one of the dimensions of the aperture pattern, thereby creating a hollow space between the foil and the exterior surface of the housing adjacent to the exit window apertures, and then sealing the circumference of the foil to the exterior surface of the housing. When the housing is evacuated, the ambient air pressure presses the foil into this hollow space and thereby stretches the foil taut over the exit window aperture to remove any potential creases or folds in the foil.