A Miniature Ionization Vacuum Sensor With a SiOₓ-Based Tunneling Electron Source

A shelved structure for the support of an electron optical column affords advantages both to the designer and the user. A lens may be removed for cleaning for example, without demounting the remaining lenses. A custom device for another example, may be placed on a shelf, substituting for the standard lens perhaps so that some specialized research may be undertaken. Especially advantageous is a shelved arrangement if the column assembly is designed to hang from a supporting structure such as a gas borne floating platform, as is the case with the system described below.As shown on the schematic, a floating platform (I) supports the electron source apparatus (2) and a U-shaped column support shelf (3). The column support shelf acts as a key for locating and supporting three struts (4) which with nuts (5) support the condenser shelf (6), the objective shelf (7), the upper projector shelf (8), and the lower projector shelf (9).

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Optical Properties of HVEM Accelerators

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114529 ◽

1975 ◽

Vol 33 ◽

pp. 180-181

Author(s):

A. Strojnik ◽

J.W. Scholl ◽

V. Bevc

Keyword(s):

Optical Properties ◽

Electron Accelerator ◽

Systematic Investigation ◽

Electron Source ◽

High Brightness ◽

The Past ◽

Wide Range ◽

Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

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A comparative study on the cold type and thermal type field emission guns used in the same electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107435 ◽

1978 ◽

Vol 36 (1) ◽

pp. 58-59

Author(s):

M. Iwatsuki ◽

Y. Kokubo ◽

Y. Harada

Keyword(s):

Electron Microscope ◽

Field Emission ◽

Signal To Noise Ratio ◽

Electron Source ◽

Resolving Power ◽

Optical Source ◽

Experimental Conditions ◽

High Brightness ◽

Illumination System ◽

Transmission Electron

On accout of its high brightness, small optical source size, and minimal energy spread, the field emission gun (FEG) has the advantage that it provides the conventional transmission electron microscope (TEM) with a highly coherent illumination system and directly improves the resolving power and signal-to-noise ratio of the scanning electron microscope (SEM). The FEG is generally classified into two types; the cold field emission (C-FEG) and thermal field emission gun (T-FEG). The former, in which a field emitter is used at the room temperature, was successfully developed as an electron source for the SEM. The latter, in which the emitter is heated to the temperature range of 1000-1800°K, was also proved to be very suited as an electron source for the TEM, as well as for the SEM. Some characteristics of the two types of the FEG have been studied and reported by many authors. However, the results of the respective types have been obtained separately under different experimental conditions.

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