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Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by time-varying magnetic fields. While the former is a conservative field, implying that no net work is done on a test charge if it goes around in a complete loop in the field, the latter is, by definition, not a conservative field; net work is done, and it is proportional to the rate of change of magnetic flux.
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Related Experiment Video

Updated: Jul 14, 2026

Electrochemical Etching and Characterization of Sharp Field Emission Points for Electron Impact Ionization

Electrochemical Etching and Characterization of Sharp Field Emission Points for Electron Impact Ionization

Published on: July 12, 2016

Electron gun using carbon-nanofiber field emitter.

Y Sakai¹, A Haga, S Sugita

¹Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.

The Review of Scientific Instruments

|May 17, 2007

Summary

A novel electron gun using carbon nanofiber emitters achieved a focal spot size under 50 micrometers for high-resolution X-ray sources. Optimized carbon nanofibers enhanced performance for advanced X-ray radiography applications.

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Last Updated: Jul 14, 2026

Electrochemical Etching and Characterization of Sharp Field Emission Points for Electron Impact Ionization

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Published on: July 12, 2016

Preparing a Celadonite Electron Source and Estimating Its Brightness

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Published on: February 2, 2012

Area of Science:

Materials Science
Physics
Engineering

Background:

Development of high-resolution X-ray sources is crucial for advanced imaging.
Electron guns are key components in generating X-rays.
Carbon Nanofibers (CNFs) offer potential as advanced electron emitters.

Purpose of the Study:

To characterize an electron gun utilizing carbon nanofiber (CNF) emitters and an electrostatic Einzel lens.
To evaluate the feasibility of this system for creating a high-resolution X-ray source.
To determine the focal spot size of the electron beam for X-ray radiography.

Main Methods:

CNFs were grown on tungsten and palladium tips via plasma-enhanced chemical-vapor deposition.
An electrostatic Einzel lens focused electron beams (10-20 keV).
Focused beams impinged on a tungsten target to generate X-rays for radiography.

Main Results:

The focal spot size of the electron beam was estimated to be less than 50 micrometers in diameter.
Superior performance was achieved using sparsely grown, larger-radius CNFs (100-500 nm).
Optimal emitter configuration involved installation at a short length (L=0.5 mm).

Conclusions:

The characterized electron gun with CNF emitters shows promise for high-resolution X-ray generation.
Optimized CNF growth and configuration significantly improve electron beam focusing and X-ray source performance.
This technology advances the development of compact and efficient X-ray sources for radiography.