scholarly journals Erratum to : Electron Microscope Equipped with Field Emission Electron Gun

Shinku ◽  
1979 ◽  
Vol 22 (10) ◽  
pp. 361-361
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Electron Gun ◽  
Emission Electron

A Compact Field Emission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 32-33 ◽  
Author(s):  
L. M. Welter ◽  
V. J. Coates
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Electron Gun ◽  
Readout System ◽  
Amplitude Control ◽  
Emission Electron ◽  
Compact Field ◽  
New Instrument ◽  
Scanning Electron

A compact field emission scanning electron microscope has been developed and modeled after the optical microscope. The new instrument consists of the field emission electron gun, an externally adjustable aperture strip containing four different hole sizes, an electromagnetic single deflection system, an electromagnetic stigmator with independent magnitude and amplitude control, an ion pumped specimen chamber, and a television readout system. No magnetic lenses are used.The field emission electron gun incorporates an electrode system which simultaneously accelerates and focuses the electrons drawn from a field emission source. Several improvements have been made in the basic gun to provide for higher tip stability and reliability. A unique pumping scheme has been incorporated in the gun to provide tip region pressures in the order of 10-9 Torr and below so that stable field emission can be routinely obtained.

Off-axis electron holography by field emission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 224-225
Author(s):  
A. Tonomura ◽  
T. Matsuda ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Electron Source ◽  
Electron Gun ◽  
Electron Holography ◽  
One Dimensional ◽  
Interference Fringes ◽  
Emission Electron ◽  
Electric Supply ◽  
Optical Laser

Although the feasibility of electron holography has been verified by several authors, it has not yet been put to practical use. This is because of the lack of a coherent electron source, such as optical laser. In practice, the number of interference fringes produced with a biprism is 200 at most, the exception being one dimensional cases. Off-axis holography requires 5,000∼100,000 interference fringes. Therefore, the useful application of electron holography in higher resolution and phase contrast electron microscopy hinges on development of a coherent electron source capable of producing 5,000 fringes or more.To realize a coherent electron source, a 100 kV field emission electron gun was developed and attached to an electron microscope. In designing the microscope,special care was taken in the column and electric supply. This was done to minimize movement of the small beam spot, which is easily disturbed from outside, so as to maintain the field emission electron beam.

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.

Microprocessor control of a field-emission scanning electron microscope (Model S-800)

1983 ◽  
Vol 41 ◽  
pp. 410-411
Author(s):  
S. Saito ◽  
Y. Nakaizumi ◽  
T. Nagatani ◽  
H. Todokoro
Keyword(s):  
Electron Microscope ◽  
Control System ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Operating Conditions ◽  
Gun Control ◽  
Electron Gun ◽  
Microprocessor Control ◽  
Emission Electron ◽  
Scanning Electron

We have developed an ultra high resolution scanning electron mícroscope utílízíng a fíeld emíssíon electron source (Fig.1). This instrument has a guaranteed resolution of 2 nm in the secondary electron image mode and it has incorporated a microprocessor control for optimized operating conditions and maximum ease of operation by various automated functions. The microprocessor control system includes field emission electron gun control, electron optical system control, and video signal control. The field emission electron gun control system includes flashing operation which is used to clean the tip surface by heating for a very short time, high voltage operation of accelerating voltage (V0) and tip voltage (V1), correction of emission current which changes with time, and correction of virtual source position which changes with a voltage ratio V0/V1. We have automated these series of operations by developing an auto FE gun control system. Fig. 2 shows details of this system.

Development of Field Emission Electron Gun for High Resolution 100KV Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 430-431 ◽  
Author(s):  
T. Someya ◽  
T. Goto ◽  
Y. Harada ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Field Emission ◽  
High Resolution Electron Microscopy ◽  
Electron Gun ◽  
Emission Source ◽  
Resolving Power ◽  
Emission Electron ◽  
Resolution Electron

The field emission source is one of the most important factors to improve the image contrast in extremely high resolution electron microscopy since it provides high brightness, very small electron source and low energy spread of electrons. In scanning electron microscopy, although the field emission source has been proved to be advantageous in the range of relatively low accelerating voltages, those capable of operating at higher accelerating voltages are now in great demand in order to improve the resolving power up to 3Å or better. In the present work, we have developed a field emission electron gun which is used with an electron microscope of accelerating voltages up to 100KV.In this development, we first made efforts to improve the method of supplying high voltages in order to eliminate the surge influence on the field emission source which are easily destroyed by a high voltage surge produced by the discharge between electrodes constituting the electron gun.

Development of 350-KV holography electron microscope equipped with magnetic type field-emission electron gun

1989 ◽  
Vol 47 ◽  
pp. 104-105
Author(s):  
J. Endo ◽  
T. Kawasaki ◽  
T. Masuda ◽  
A. Tonomura
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Gun ◽  
Electron Holography ◽  
Electron Microscopic ◽  
Magnetic Lens ◽  
High Brightness ◽  
Emission Electron

A field-emission electron gun is one of the most epoch-making technologies in an electron microscopic world. In a transmission electron microscope, a high brightness of this beam has been effectively employed for electron-holographic measurements, though the value is not still high enough. Development of a higher brightness beam will promise to open up unattained application possibilities of electron holography such as high resolution and high sensitivity interferometry.We developed the field emission electron microscope for electron holographic applications. Special attentions were paid for high brightness, large beam current and easy operation. Figure 1 is a schematic diagram of the electron gun. In order not to deteriorate the original high-brightness feature of the beam by the aberrations in the gun and the condenser lenses, a magnetic lens was installed between the tip and the extraction anode so that the total aberration effect might be minimized. Field emitted electron beam is converged by the magnetic and the electrostatic lenses, and accelerated in a ten-stage accelerator which is made of porcelain.

Interference Experiments with a Field Emission Electron Miscroscope

1974 ◽  
Vol 32 ◽  
pp. 386-387
Author(s):  
J. Munch ◽  
E. Zeitler
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Design Principles ◽  
Electron Gun ◽  
University Of Chicago ◽  
Emission Electron ◽  
The University ◽  
Better Than

We have modified a Hitachi HU 12 electron microscope by replacing the thermionic electron gun with a field emission gun. The design principles of this gun are substantially the same as those used in the scanning microscopes developed at the University of Chicago by A. V. Crewe and his collaborators. To accommodate the field emission gun in the conventional column two differentially pumped stages were employed, assuring a vacuum of better than 2 x 10−10 Torr in the tip region.

Development and applications of an analytical electron microscope with a field emission electron gun

1990 ◽  
Vol 25 (4) ◽  
pp. 375-395 ◽  
Author(s):  
A. Koreeda ◽  
T. Ishibashi ◽  
K. Shimizu ◽  
M. Tomita ◽  
C. Kimura ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Electron Gun ◽  
Emission Electron ◽  
Analytical Electron ◽  
Analytical Electron Microscope

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

Characteristics and Application of Temperature-Field Emitters

1975 ◽  
Vol 33 ◽  
pp. 144-145
Author(s):  
N. Tamura ◽  
T. Goto ◽  
Y. Harada
Keyword(s):  
Temperature Field ◽  
Electron Microscope ◽  
Field Emission ◽  
Resolving Power ◽  
High Brightness ◽  
Field Emitters ◽  
Emission Electron ◽  
Sufficient Stability ◽  
Scanning Electron ◽  
Illuminating System

On account of its high brightness, the field emission electron source has the advantage that it provides the conventional electron microscope with highly coherent illuminating system and that it directly improves the, resolving power of the scanning electron microscope. The present authors have reported some results obtained with a 100 kV field emission electron microscope.It has been proven, furthermore, that the tungsten emitter as a temperature field emission source can be utilized with a sufficient stability under a modest vacuum of 10-8 ~ 10-9 Torr. The present paper is concerned with an extension of our study on the characteristics of the temperature field emitters.

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