The Effect of Injection System Dynamics on Limiting Current Behavior in an Ideal Planar Diode

摘要

The report describes an improvement in the digital computer simulation of high perveance beams in a region confined by two equipotential parallel planes. The improvement consists in considering a triode model where the first region is an acceleration region or a cathode-grid region and the second region the usual drift region between two equipotential parallel planes. The entrance plane of the drift region (grid plane) is supposed perfectly permeable to the electrons travelling in both directions. The usual assumption of returning electron annihilation at the entrance plane is not made. The improvement was tested by comparing the results with those of the previously studied diode model (AD-603 078). The triode model was also tested against errors introduced by the discrete injection of charges. The use of the triode model gave rise to problems related to the discontinuity of the acceleration when the charges pass through the grid and the effect of the space charge upon the emission of the charges from the cathode. (Author)