ELECTRON-EMISSION FROM LEAD-ZIRCONATE-TITANATE CERAMICS

We report extensive experimental data on electron emission from lead-z irconate-titanate ferroelectric ceramics. A 1-2 MV/m pulse is applied to a gridded ferroelectric cathode and diode currents of up to 120 A/c m(2) are measured across an A-K gap of 5 X 10(-2) m, with the anode at 35 kV. Both the current and the anode voltage pulse duration may exte nd to several microseconds. The. measurements extend previously report ed data by nearly two orders of magnitude in the diode voltage and by a factor of more than 3 in the diode spacing. Two major regimes of ope ration were identified. In the first similar to 1 mu s the ferroelectr ic cathode controls the electron how through the diode. Beyond this ti me plasma effects dominate the current flow. The results are of import ance to the development of novel cathodes for high current electron be am generation. (C) 1998 American Institute of Physics. [S0021-8979(98) 06401-9].