A new type of cathode-ray tube with a crossed-field gun

This paper introduces a new type of cathode-ray tube with a crossed-field electron gun which produces an electron beam in a region where a nonuniform magnetic field and an electric field cross perpendicularly. The new configuration gives increased freedom in the design of crossed-field guns. As a result, a long, directly heated cathode can be readily applied to a gun structure which makes high perveance and instant operation possible with much improved cathode heating efficiency. The new gun provides ion trap action by virtue of a magnetic field which separates ions from electrons due to the difference in their masses. A new type of cathode-ray tube using this gun not only demonstrates these features but also requires relatively low operational voltages for beam acceleration and control electrodes. The paper includes an analysis of electron motion in a crossed field with a nonuniform magnetic field. It also shows practical configuration of electrodes and current characteristics of the gun.