The triode electron gun based on carbon lattice field emission cathodes for vacuum electron beam devices

1997 ◽  
Keyword(s):  
Electron Beam ◽  
Field Emission ◽  
Electron Gun ◽  
Lattice Field ◽  
Field Emission Cathodes

Integrated tungsten nanofiber field emission cathodes selectively grown by nanoscale electron beam-induced deposition

2005 ◽  
Vol 86 (18) ◽  
pp. 183106 ◽  
Author(s):  
X. Yang ◽  
M. L. Simpson ◽  
S. J. Randolph ◽  
P. D. Rack ◽  
L. R. Baylor ◽  
...  
Keyword(s):  
Electron Beam ◽  
Field Emission ◽  
Electron Beam Induced Deposition ◽  
Field Emission Cathodes

Development of a 1-MV Field-Emission Electron Microscope III. Electron Optical Design and Development of Field-Emission Electron Gun

2000 ◽  
Vol 6 (S2) ◽  
pp. 1142-1143
Author(s):  
Takaho Yoshida ◽  
Takeshi Kawasaki ◽  
Junji Endo ◽  
Tadao Furutsu ◽  
Isao Matsui ◽  
...  
Keyword(s):  
Electron Beam ◽  
Field Emission ◽  
Optical Design ◽  
Electron Gun ◽  
Electron Holography ◽  
Optimized Design ◽  
Emission Electron ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Aharonov Bohm

Bright and coherent electron beams have been opening new frontiers in science and technology. So far, we have developed several field-emission transmission electron microscopes (FE-TEM) with increasing accelerating voltages to provide higher beam brightness. By using a 200-kV FE-TEM and electron holography techniques, we directly confirmed the Aharonov-Bohm effect. A 350-kV FE-TEM equipped with a low-temperature specimen stage enabled us to observe moving vortices in superconductors.2 Most Recently, we have developed a new 1-MV FE-TEM with a newly designed FE gun to obtain an even brighter and more coherent electron beam.Electron beam brightness, Br, defined in Figure 1, is suitable for measuring the performance of electron guns, since both lens aberrations and mechanical/electrical vibrations contribute to a decrease in beam brightness, and beam coherency is proportional to (Br)1/2. Therefore, we optimized design of the illuminating system and its operation by maximizing the electron beam brightness.

scholarly journals Electron Diagnostics for Extreme High Brightness Nano-Blade Field Emission Cathodes

Instruments ◽  
2019 ◽  
Vol 3 (4) ◽  
pp. 57
Author(s):  
Gerard Lawler ◽  
Kunal Sanwalka ◽  
Yumeng Zhuang ◽  
Victor Yu ◽  
Timo Paschen ◽  
...  
Keyword(s):  
Electron Beam ◽  
Field Emission ◽  
Transverse Energy ◽  
Modern Science ◽  
Damage Threshold ◽  
X Rays ◽  
The Novel ◽  
High Brightness ◽  
Nanoscale Structure ◽  
Field Emission Cathodes

Electron beams are essential tools in modern science. They are ubiquitous in fields ranging from microscopy to the creation of coherent ultra-fast X-rays to lithography. To keep pace with demand, electron beam brightness must be continually increased. One of the main strategic aims of the Center for Bright Beams (CBB), a National Science Foundation Science and Technology Center, is to increase brightness from photocathodes by two orders of magnitude. Improving the state-of-the-art for photoemission-based cathodes is one possibility. Several factors have led to an alternative design becoming an increasing necessity; the nanoscale structure. Field emission sources from nano-tips would be an ideal candidate were it not for their low current and damage threshold. A 1-dimensional extended nano-fabricated blade, i.e., a projected tip, can solve the problems inherent in both designs. The novel geometry has been demonstrated to produce extremely high brightness electron beam bunches and is significantly more robust and easier to manufacture than traditional photocathodes. Theory indicates electron emission up to keV energies. We thus present a system of diagnostics capable of analyzing the cathodes and assessing their viability. The diagnostics are designed to measure the electron spectrum up to keV energies, with sub meV resolution at <100 eV, mean transverse energy (MTE), emission uniformity, and cathode lifetime. We also report preliminary data on total extracted charge and maximum detectable electron energy with a simplified retarding field spectrometer.

scholarly journals Field-emission electron gun for a MEMS electron microscope

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Michał Krysztof
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Field Emission ◽  
Control Function ◽  
Electron Gun ◽  
Emission Current ◽  
Electron Beam Current ◽  
Anode Current ◽  
Current Limit ◽  
Emission Electron

AbstractThis article presents a field-emission electron gun intended for use in a MEMS (microelectromechanical system) electron microscope. Its fabrication process follows the technology of a miniature device under development built from silicon electrodes and glass spacers. The electron gun contains a silicon cathode with a single very sharp protrusion and a bundle of disordered CNTs deposited on its end (called a sharp silicon/CNT cathode). It was tested in diode and triode configurations. For the diode configuration, a low threshold voltage <1000 V and a high emission current that reached 90 µA were obtained. After 30 min of operation at 900 V, the emission current decreased to 1.6 µA and was stable for at least 40 min, with RMS fluctuation in the anode current lower than 10%. The electron beam spot of the source was observed on the phosphor screen. In the diode configuration, the spot size was the same as the emission area (~10 µm), which is a satisfactory result. In the triode configuration, an extraction electrode (gate) control function was reported. The gate limited the emission current and elongated the lifetime of the gun when the current limit was set. Moreover, the electron beam current fluctuations at the anode could be reduced to ~1% by using a feedback loop circuit that controls the gate voltage, regulating the anode current. The developed sharp silicon/CNT cathodes were used to test the MEMS electron source demonstrator, a key component of the MEMS electron microscope, operating under atmospheric pressure conditions. Cathodoluminescence of the phosphor layer (ZnS:Ag) deposited on the thin silicon nitride membrane (anode) was observed.

Sign in / Sign up

Export Citation Format

Share Document