Volume 1, Issue 1
Berkeley's Scientific Legacy
1955: Emilio Segrè, Owen Chamberlain, and the matter of antimatter
During the fall of 1955, a blackboard at Lawrence Berkeley National Laboratory helped physicists Emilio Segrè and Owen Chamberlain keep track of two very important, but very different, tallies. One side of the board held the scores from that year's World Series, in which the Brooklyn Dodgers ultimately beat the Yankees. The blackboard was also where Segrè and Chamberlain kept a running tally of how many elusive antiprotons they observed after discovering the very first one.
Left to right are Dr. Emilio Segrè, Dr. Clyde Wiegand, Dr. Edward Lofgren, Dr. Owen Chamberlain and Tom Ypsilantis, then a graduate student. The photograph was taken at Lawrence Berkeley Laboratory in October, 1955 at the time of the discovery of the antiproton. (Courtesy LBL)
The hunt for antimatter began in earnest in 1932, with the discovery of the antielectron, or positron. Creating an antiproton though was far more difficult, requiring nearly 2,000 times the energy. In 1955 though, the Berkeley Bevatron--then the most powerful "atom smasher" in the world--went online, providing the scientists with the energy they needed to make antiprotons.
The next challenge was determining whether they succeeded. After all, almost instantly after an antiproton appears, contact with a proton annihilates them both. To detect the particles, Segrè and Chamberlain devised a maze of magnets and electronic counters through which only antiprotons could pass.
"We had to sort them out and weigh them within much less than one-millionth of a second," Segrè recalled later. "If we had wanted to have them for a longer time, we would have to dig a tunnel in the Berkeley hills to run after them."
After several hours of bombarding copper with protons accelerated to 6.2 billion electron volts of energy, the scientists counted a total of 60 antiprotons. Most likely, the discovery of one would have been sufficient to have earned them the 1959 Nobel Prize in Physics.
Professor Emilio Segrè in 1954 (Courtesy LBL)
Professor Owen Chamberlain in 1955 (Courtesy LBL)