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This tutorial lecture provides an introduction (suitable for those relatively new to the subject) to methods available for the extraction of emitter characterization data from field electron emission (FE) current-voltage data, to the problems of doing this reliably, and to some recent progress in developing better understanding of the issues involved.
With a large-area field electron emitter, when an individual post-like emitter is sufficiently resistive, and current through it sufficiently large, then voltage loss occurs along it. This conference presentation provides a simple analytical and conceptual demonstration that this voltage loss is directly and inextricably linked to a reduction in the field enhancement factor (FEF) at the post apex,...
A control circuit to stabilize the flux of electrons transmitted through an extractor electrode is presented. By controlling the emission current a fluctuation with a standard deviation of 0.015% is observed. However, the achievable stability of the transmitted electron current is limited due to a variation of the extraction grid current ratio showing a standard deviation of 4.33%. By regulating the...
Needle-like single crystal diamond structures were obtained by combination of the plasma enhanced chemical vapor deposition (CVD) and selective oxidation techniques. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and the intensity of the femtosecond laser focused on the needle. Moreover, a new set-up based...
Electron emission from single hot carbon nanotubes (CNTs) heated by self-Joule heating is in situ studied inside a scanning electron microscope (SEM) and the emitted electrons are detected by the Everhart-Thornley detector. Periodic pulsed electron emission is observed to overlap on a dc background. The period of the pulses is measured to be 292 ms with no dependence on the bias voltage applied to...
An in-situ fabrication technique based on ion track etched template electrodeposition of metallic nanocones was used for the production of field emitter cathodes. Gold nanocones with a height of 24 microns, a base diameter between 3 to 4 microns and a tip diameter below 300 nanometers were deposited on a circular electrode with a diameter of 2.5 mm. The integral field emission (FE) measurements of...
Carbon nanotubes (CNTs) have attracted much attention as field emitters for x-ray tubes because of their excellent properties such as rapid operation speed, wide operation range, reduced size, light weight, and no necessity of emitter heating. This study fabricated the CNT emitters by screen-printing the CNT paste, followed by firing at 435 °C and vacuum heat treatment at 830 °C. During the high-temperature...
In this paper, we report our first experimental findings that evidence the vacuum level in the test chamber can be responsible for variation in the field emission (Fowler-Nordheim) response of an electron source. This situation is exampled using a carbon nanotube sample measured in a parallel plate configuration.
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