After reading about the use of electrons in a particle accelerator to “cool” the antiprotons in a secondary ring, I have a question. Is it possible to make a long straight stretch of the main ring feed high-energy electrons in at an oblique angle to a deflection magnet and thereby bend the electrons into the antiproton stream to cool it? At the next deflection magnet, the electrons would once again be bent through a relatively sharp angle and go back toward the center of the main ring. If the electrons could then be “cooled” and circled around to the first deflection magnet, they could be recycled many times to continue cooling the antiprotons.

Mike Bushroe
Tucson, Ariz

The idea of electron cooling in an accelerator’s main ring is good in principle, says physicist Sergei Nagaitsev of the Fermi National Accelerator Laboratory in Batavia, Ill. Indeed, accelerator specialists in New York State plan to build an electron-cooling system into the main ring of an accelerator there, he notes .—P. Weiss