Electron emitter

This soft, silver white metal reacts with air and water. The oxide is applied in optical glasses with high refractive indices (special lenses for powerful cameras and telescopes). Used for special effects in optoelectronics and electronics. Lanthanum exhibits catalytic properties. It is a component of flint and battery electrodes. Lanthanum boride (LaB6) is the superior electron-emitter for electron microscopes. Lanthanum is the first of the series of 14 lanthanides, also called the "rare-earth" metals, whose inner N shells are filled with electrons. They do not belong on the "red list" of endangered species they are neither rare nor threatened with depletion. China is particularly rich in lanthanide ores. 

The TSP interface was very popular and attractive to chromatogra-phers in the 1980s, as a result of its ease of operation and dependable performance. Commercial TSP LC/MS systems are equipped with an electron emitter filament to enhance the Cl process. 

The field emission current from an area A of a field electron emitter surface of work function 0O at a field F is given by... 

The samples were then mounted and coated with an Au/Pd alloy and placed in a Cambridge Stereoscan (S4-10), equipped with a LaB6 electron emitter. 

Carbon nanotubes have been studied extensively since their first observation in 1991 by Ijima [1], Several techniques of preparation have been developed such as laser ablation [2], arc electric procedure [3] or decomposition of hydrocarbides [4], The tremendous interest of scientists towards this new class of carbon materials is due to several reasons. First, the electronic properties are of primary importance on a fundamental point of view, but more importantly, potential applications are proposed every day [5], far beyond the use of nanotubes as electron emitters in flat screen as reported some time ago. 

Flat AIN films were fabricated into gated cathode structures [15]. The films included thin AIN on SiC and a graded layer with a concentration graded from GaN to nearly 100% AIN at the surface. The structures employed an oxide spacer layer and an Al film on the oxide served as the grid electrode. The results for both structures were similar. Devices worked for a few minutes, but they exhibited grid currents ranging from 10 to 1000 times the collector current. These preliminary measurements suggest that further materials research on the surfaces of nitrides may lead to room temperature electron emitter structures. 

The return beam vidicon (Fig. 9) uses a photocathode to detect the light image. The photoelectrons are formed on a target composed of a secondary electron emitter similar to the dynodes in a photomultiplier, and secondary electrons produced are collected by a mesh, leaving the target with an image stored in... 

The use of DLC in field emission displays is growing because of its properties as an electron emitter for field emission array applications. By controlling the sp /(sp + sp ) ratio the activation energy can be... 

Electron emitter (W, W-Th02, W-La203, porous W). Other elements are better emitters, but W has an extremely low vapor pressure and can be used at higher temperatures (it keeps the filament free of gas contamination, which would decrease emission). Therefore, W is practically the only material used in this field. Timgsten can be used as cold (field emission) and as hot emitter (thermionic emission). The principles are explained in Section 1.2.7. Field emission cathodes are used in field emission electron microscopy (FESEM). Examples of thermionic emission are manifold ... 

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