San José State University
Thayer Watkins
Silicon Valley
& Tornado Alley

The Interactions of Electrons and Photons

The motivation for this webpags is a description of an experiment given by Edwin T. Jaynes of the Arthur Holly Compton Laboratory of Physics at Washington University in St. Louis, Missouri.

I gave a talk on the general principles for generating light from electrons, which contained some speculation about possible explanations of the then much discussed 'blue electron' effect reported by Schwarz & Hora (1969). Here 50 kev free electrons are irradiated by blue light from an Argon laser, then drift 20 cm and were reported to emit the same color blue light on striking an alumina screen which is normally not luminescent.

Jaynes' article is the first in the published proceedings of a conference held in 1990 entitled ELECTRON WORKSHOP. The proceedings were described on the cover as follows.

The stupendous success of the Dirac equation and quantum electrodynamics have established the electron as the best understood of the fundamental constituents of matter.

It is remarkable that the proceedings commences with an article dealing with the unexplained phenomenon of electrons somehow capturing the energies of photons, which flit about at 186,000 miles per second, and store it in some manner unknown. However this is not the only instance of the transverse illumination of a beam of electrons resulting in some puzzling change in the behavior of the beam.

The eminent physicist Richard Feynman, in another situation, remarked that if the beam of electron used in the two slit experiment are irradiated transversely the interference patterns of the two slit experiment do not develop. Feynman asserts that no one knows why this occurs.

These two experiments bring to mind the remark of Albert Einstein.

All these 50 years of conscious brooding have brought me no nearer to the answer to the question 'What are light quanta?'. Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken."

So collected here are links to studies dealing with the interaction of electrons and photons. The interactions probably occur for other particles but the experiments were carried out with electrons because of their convenience.

(To be continued.)

HOME PAGE OF applet-magic