A high-perveance ferroelectric cathode with a narrowed electron energy spread

Abstract

A pulsed ferroelectric electron cathode with a current density of up to 45 A based on ceramic is presented. The experimental set-up for the cathode triggering allowed us to achieve a perveance of more than P and an energy spread in the generated electron beam as low as 100 eV (FWHM).

Peculiarity of Low Density Plasma-Assisted Charge Emission Produced at LATGS Crystal Surface

“…2 and 3) that the surface plasma processes, generated at the LATGS sample surface under the same external field magnitude, are additionally gained during switching of the polarization contrary to that observed during dielectric charging of the sample. It can also be assumed that the energy of charges registered under our experimental condition reflects dynamically changing surface potential distribution and/or surface plasma potential [8,11,17].…”

“…About twenty years later, electron current with density of the order of a few Acm −2 was produced on PLZT ceramic samples subjected to the short (10 −7 s) negative HV pulse (Gundel et al [12]). During the last two decades, mainly PZT-and BaTiO 3 -based ceramic samples with selected composition and polarization state [13][14][15][16][17][18][19][20][21], and even TGS single crystals [22] were examined under different experimental conditions because of their possible application as cold cathodes in different areas of technology, for example in vacuum electronics, accelerators, plasma sources, lasers, triggering systems, etc. It should be stated that for the most of strong electron emission experiments, the sample studied were subjected to the pulse (10 −7 − 10 −6 s) electric field exceeding 10 4 V/cm and only in some experiments the pulse duration was as long as 10 −3 s [22].…”

Energy distribution of plasma-assisted electron and ion emission from TGS single crystals

“…Because the uncompensated charges arising on a polar sample surface in a region adjacent to the electrode edges are non-homogeneously distributed, a tangential component of the depolarizing field can lead to the initiation of surface discharge (plasma) formation. It can be assumed that the energy of charges registered for this low density plasma-assisted electron and ion emission processes can reflect dynamically changing surface potential distribution and/or plasma potential distribution [13,20]. Up to now, however, the mechanism leading to the appearance of electron energy peak at 70-80 eV for second emission maximum has been unknown.…”

“…Later, many research groups at laboratories all over the world have investigated these high density electron emission phenomena because of their potential applications in different areas of technology, for example in vacuum electronics as a new type of cold cathode. For these purposes many kinds of perovskite oxidebased ceramic samples with selected composition and phase sequences were examined under different experimental conditions [7][8][9][10][11][12][13][14][15]. Two points of view on this high density electron emission are presented in available literature, i.e., fast polarization reversal induced electron emission and/or plasma-assisted electron emission.…”

Ferroelectric cathodes in transverse magnetic fields

“…Cathodes based on the effect of ferroelectric emission were successfully used in several experimental setups with applied magnetic field 11,12,13,14,15 . Indeed, ferroelectric cathodes are able to produce uniform electron beams with kiloampere currents and low beam divergence, without any delay of the beam with respect to the accelerating voltage application and without vacuum deterioration 16 .…”