A Century of the Electron

Mr. Richard Hoyt Lee
Argonne National Laboratory
Argonne, Illinois

November 20. 1998

The electron was discovered April 30, 1897 by Joseph John Thompson, who called it corpuscle before the Royal Institution. For several years, it was a scientific curiosity, but later became the foundation for a whole new field of electronics. It was actually William Crookes who did much of the original work on "cathode rays" and their behavior. Later, the properties of electrons were found to be much more complicated than we thought, leading to the particle and wave properties described by quantum mechanics. The application of electronics to microscopy was begun once electron optics and electron beam devices were developed. The earliest work was done by Ruska in 1931-36, followed by von Ardenne in 1938, using a high voltage electron gun, scanning control coils, and a CRT for viewing. Electron probe microanalysis became important in the 1940s and in 1949 Castaing built the first microprobe and developed the elemental analysis algorithms, We now recognize that, in addition to secondary electron images, we can, with the proper detector, obtain backscatter electron images, cathodoluminescence signals, X-ray elemental distribution, absorbed current images, and crystal orientation.

The future of microscopy has been dramatically improved with the assistance of the computer, both for image processing and microanalysis. The future of microscopes is presented in terms of possible hardware.

Bio Sketch
Richard H. Lee studied metallurgy at the Milwaukee School of Engineering. At Argonne National Laboratory he is involved in various fields of materials research and microscopy. His expertise in sample preparation, cleaning, polishing, and microscopy is currently shared between both Argonne's Emerging Technology Division and Advanced Photon Source, Experimental Beamlines group.

Minutes from the SMSI Meeting of November 20. 1998
The meeting was called to order at 7 PM. by Bill Mikuska with a reminder that amateur night would be held on December 18th and that anyone wishing to make a presentation should contact him for scheduling.

It was announced that Dr. John McCormick would address the After Christmas Christmas party on January 22.

Richard Lee spoke on "A Century of the Electron", focusing on scientific pioneers whose work laid the foundation for its discovery and exploitation through the development of a wide range of technological innovations which continue to this very day. The story of the electron to no small degree parallels many of the life transforming developments of the past hundred years.

As a discoverer of electricity, Ben Franklin noted its polar nature when he coined the terms "positive" and "negative" charge. Volta pioneered research in electrochemistry and produced the voltaic cell or battery. Michael Faraday's revolutionary work in field theory, electrolysis and magnetic forces was given mathematical form by Maxwell. It was at this time that a connection between electromagnetic force and light was drawn.

Crooke's work with vacuum cathode ray discharge tubes paved the way for the actual discovery of the electron by J. J. Thompson in 1897. T. A. Edison and Tesla, with his revolutionary alternating current system, brought the world into the age of electricity. Robert Millikan measured the charge on an electron; von Ardenne invented a powerful electron gun which lead to the first Scanning Electron Microscope; significant advances in imaging technique followed, including the deve!opment of the T.E.M.

The electronics age continues to blossom through technological "miracles" such as transistors, integrated circuit chips, television and computers, all virtually unthinkable until the very recent past. Microscopy, as it has developed in the twentieth century, parallels increased insight into the elusive electron and the quantum world it inhabits.

In the question and comment period following the presentation the issue was raised as to how the cause of microscopy could be better marketed. Garth Ziemba pointed out that PLM delivers no print out; it demands a knowing doer at thc helm and therein may lie the problem.

Thc meeting was adjourned at 8 PM. with a friendly reminder that articles for the upcoming issue of µ-Notcs were being accepted.

Submitted by: John Macdonald, Recording Secretary