Bell Labs: Positron and plasma research

Reflections by A. P. Mills Jr. and C. M. Surko

Allen Mills Jr. joined Phil Platzman’s Fundamental Physics Department 1115 in the fall of 1975. Mills’s path from Brandeis University to Bell Labs was unconventional. For a long time Marv Leventhal at Bell Labs had been trying to measure the fine structure constant using Lamb shift measurements on the hydrogen atom to understand the nature of the electromagnetic interactions. Stephen Berko was also interested in the possibility of an equivalent Lamb shift in the positronium atom. In 1972 a group in London reported a new way to create slow positronium atoms in great number so that an equivalent experiment on positronium could be performed. Berko called T. C. Griffith in London to ask which of the two postdocs on the experiment was responsible for the amazing work. The answer was that Karl Canter was the key person involved and was not listed as first author simply because of the Griffith group’s habit of alphabetical authorship. Canter was quickly hired as a postdoc at Brandeis and within about a year many of the mysteries of positronium were made clear with a triplet of discoveries by the Berko, Canter, and Mills team: the formation of positronium in solid targets, the observation of positronium Lyman-alpha radiation, and the fine structure measurement in the first excited state of positronium. In response to these three papers, Platzman asked Berko which of the two postdocs he should hire at Bell Labs. The choice was Mills, who began his work at Bell Labs by measuring the mobility of positrons in a single crystal of germanium with the expert help of Loren Pfeiffer. This was just the sort of experiment that Phil Platzman enjoyed.

Clifford M. Surko passed away on December 7, 2024, after a brief illness. Cliff received his PhD from Berkeley in 1968 under Frederick Reif’s guidance. He joined Bell Labs in 1968 and became department head of Semiconductor and Chemical Physics in 1982. In 1988 he moved to the University of California, San Diego, where he led the positron group. A winner of the James Clerk Maxwell Prize for Plasma Physics in 2014, he made diverse contributions to the fields of plasma physics, atomic physics, nonlinear dynamics, and solid state physics. He is probably best known for his work studying waves and turbulence in tokamak plasmas, and later for a buffer gas positron trap invented to study antimatter in experiments worldwide.

Cite this resource

A. P. Mills Jr. and C. M. Surko, “Positron and Plasma Research,” History of Bell Labs Physical Research, 1980–2006 collection, edited by Arthur Ramirez, Cherry Murray, and David Bishop, American Institute of Physics, 2026, https://www.aip.org/history/bell-labs-physical-research-1980-2006/positron-and-plasma-research.