Operation of ferroelectric cathodes with control grid

Abstract

Summary form only given, as follows. Results of experimental investigation of the generation of electron beams in a planar diode with a ferroelectric plasma cathode having a control grid are investigated. The plasma is formed at the surface of a BaTiO/sub 3/ ferroelectric sample as a result of incomplete surface discharge when a driving pulse is applied to the sample. It is shown that in the case of plasma formation prior to the application of the accelerating voltage, the diode operates in a plasma prefilled mode. This mode of the diode operation occurs because of the formation of a fast plasma flows which fill the anode-cathode gap during the first 100-200 ns from the start of the driving pulse. We present results of experimental studies of the plasma parameters produced by a large area ferroelectric plasma cathode and of the generation of electron beams by the ferroelectric cathode with a control grid. The use of the control grid allows a suppression of the fast plasma flows. Measurements of the density of the plasma and its velocity allows the prediction of the control grid biased potential which is required for the suppression of the plasma flows. The measurements of the decrease of the plasma density of these flows on the grid potential showed the high efficiency of the control grid operation. The successful operation of the electron diode using the ferroelectric plasma cathode with the biased control grid, when the plasma prefilling of the anode-cathode gap was almost completely avoided, is demonstrated.