Electron beam generation in a diode with different ferroelectric cathodes

We present experimental results of electron beam generation in a diode with cathodes made of BaTi solid solution and prepoled and unpoled PZT ferroelectrics without a screening grid in front of them. The diode operates with an accelerating pulse of similar to200 kV and similar to300 ns duration. It was found that although a surface plasma is always formed as a result of the application of a driving pulse, the beginning of the electron emission does not always coincide with the start of the accelerating pulse. Namely, it was shown that the application of the accelerating pulse at the same time with the driving pulse leads to simultaneous electron emission from the surface plasma only in the case of coincidence of the driving and accelerating electric field directions. In the opposite case, electron emission starts only at the end or at the fall of the driving pulse for the BaTi and PZT samples, respectively. Also, it was found that the electron beam current density distribution corresponds to the plasma emission spots which appear at the ferroelectric surface. (C) 2003 American Institute of Physics.