High‐current density, high‐brightness electron beams from large‐area lanthanum hexaboride cathodes

1988 ◽  
Vol 63 (8) ◽  
pp. 2552-2557 ◽  
Author(s):  
P. Loschialpo ◽  
C. A. Kapetanakos
Keyword(s):  
Current Density ◽  
Electron Beams ◽  
High Current Density ◽  
Lanthanum Hexaboride ◽  
High Current ◽  
Large Area ◽  
High Brightness

Philips electron microscopes: Applications trends—design advances

1992 ◽  
Vol 50 (2) ◽  
pp. 976-977
Author(s):  
M.N. Thompson
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Total Current ◽  
High Current ◽  
Large Area ◽  
Small Probe ◽  
Field Emitters ◽  
Chemical Resolution ◽  
Electron Microscopes ◽  
Reasonable Choice

Application trends in the 1990's will continue to be driven by the pursuit of materials characterisation to higher levels of structural and chemical resolution. Due to the information-limit and current-density limitations of LaB6 sources, further advancements will require better electron guns. The choice of guns includes Cold, Thermally-assisted Cold and Schottky Field Emitters. For SEM and STEM the Cold Field Emitter is a reasonable choice, because the primary criterion for small-probe techniques is current density. This logic doesn't apply to TEMs, which require both high current density for small probes and high total current for large-area illumination at various TEM magnification levels. Table 1 compares Schottky and Cold Field emitters in different applications and microscope construction. In view of its performance (Figs. 1 and 2), the Field Emission Gun is expected to have a major impact on TEM in the 1990's.

NEEDLE CATHODES FOR HIGH-BRIGHTNESS BEAMS

2007 ◽  
Vol 22 (22) ◽  
pp. 3784-3793 ◽  
Author(s):  
C. H. BOULWARE ◽  
J. D. JARVIS ◽  
H. L. ANDREWS ◽  
C. A. BRAU
Keyword(s):  
Field Emission ◽  
Current Density ◽  
High Current Density ◽  
Thermionic Emission ◽  
High Current ◽  
High Brightness ◽  
Electron Sources ◽  
Schottky Effect ◽  
Surface Electric Field ◽  
Very High

At the tips of sharp needles, the surface electric field is enhanced by many orders of magnitude. This intensifies thermionic emission and photoemission of electrons through the Schottky effect, and reduces the effect of space charge. The increased current density improves the brightness of electron sources by orders of magnitude. In addition, at very high fields (>109 V/m ), field emission and photo-field emission produce very high current density. Arrays of needles can be used to achieve high total current.

Static and dynamic characterization of large-area high-current-density SiC Schottky diodes

2001 ◽  
Vol 48 (2) ◽  
pp. 349-352 ◽  
Author(s):  
D.T. Morisette ◽  
J.A. Cooper ◽  
M.R. Melloch ◽  
G.M. Dolny ◽  
P.M. Shenoy ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Schottky Diodes ◽  
High Current ◽  
Dynamic Characterization ◽  
Large Area

High-current-density subnanosecond electron beams formed in a gas-filled diode at low pressures

2006 ◽  
Vol 32 (11) ◽  
pp. 948-950 ◽  
Author(s):  
E. Kh. Baksht ◽  
M. I. Lomaev ◽  
D. V. Rybka ◽  
V. F. Tarasenko
Keyword(s):  
Current Density ◽  
Electron Beams ◽  
High Current Density ◽  
High Current ◽  
Low Pressures
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