NOTE: Please see the end of this release for details about the May 24 opening of CEBAF in Newport News. JAMES MCCARTHY: STORY OF A SMASHING SUCCESS CHARLOTTESVILLE, Va., May 15 -- It has taken almost 20 years and dozens of loops through the Southeast for James McCarthy to make his dream of sending electrons on a microsecond-long trip around a mile-long race track come true. McCarthy, the W.L. Lyons Brown Professor of Physics at the University of Virginia, dreamed up what is now called the Continuous Electron Beam Accelerator Facility (CEBAF) in 1979. The idea was to build a kind of microscope that would use a slender beam of electrons accelerated to almost the speed of light to peer into the heart of the atom and back to the dawn of time. The scientific and engineering obstacles to this idea were daunting enough, but McCarthy had the even more outrageous notion of locating this wonderful instrument in the Southeast. The Southeast was, to put it bluntly, considered a scientific backwater by the big players in particle physics. "Lots of people thought I was crazy when I proposed this," McCarthy admits. Thus, when the dignitaries arrive in Newport News, Va., on May 24 to officially open CEBAF, McCarthy will be forgiven if he gloats just a little. McCarthy came to his profession in a roundabout manner. He grew up in California's San Fernando valley and, although he'd always enjoyed math as a child, physics was not offered at the high school he attended. An English major at Occidental College (he still collects first editions of classic literature), McCarthy originally tackled physics as a way to help his girlfriend with her homework in the subject. "They made me take remedial physics when I was starting my doctorate at Stanford," McCarthy recalls. Stanford University in the 1960's was a tumultuous place and McCarthy took his stand with other graduate students in blockading the physics building to protest the Vietnam War. Soon, however, he returned to his studies with Stanford physicist Robert Hofstadter, who won the 1961 Nobel Prize in Physics for his discovery that protons are not fundamental components of atoms but are made of still more basic units, now called by the whimsical name of quarks. Hofstadter used a linear particle accelerator to conduct his experiments and it was there that McCarthy formed his abiding interest in smashing atoms. The difference between the accelerator McCarthy used in his graduate student days and the one taking shape 25 feet below ground at Newport News, however, could not be more pronounced. Historically, accelerators smashed atoms by bombarding them with relatively large particles, usually protons. In comparison with the point-like and essentially massless electron, whose behavior is well understood by physicists, protons are big and clumsy and their actions cannot be easily directed. When fast-moving protons collide with atoms, the "wreckage" can -- with difficulty -- be studied for clues about the atoms' inner contents. Theoretically, a fine, highly accelerated stream of electrons would be a more precise tool for slicing apart atoms and attempting to see how their nuclear components (the neutrons and protons) fit together. As one physicist associated with CEBAF has phrased it, the difference between proton accelerators and electron accelerators is like difference between using a hammer to open up and study a watch and using a needle. McCarthy joined the University of Virginia's faculty in 1970. Among the culture shocks he says he experienced with his move East was the near absence of women on the U.Va. Grounds. (Women undergraduates were first admitted to U.Va. in 1970.) For about ten years, he continued his research using proton accelerators. Then, in 1979, the world's top nuclear physicists gathered in Charlottesville to discuss the future of the field. Leading scientists from Argonne National Laboratory, MIT, and Californian universities as well as European experts agreed to meet at U.Va. because, as McCarthy remembers, "it was neutral territory." The idea of electron accelerators was hotly debated. True, the scientists agreed, accelerated electrons could be a more refined tool for examining atoms. The problem was, McCarthy says, no one knew how to build a machine that could get a continuous beam of electrons accelerated to the insanely fast speeds required for such atomic surgery. Following this conference, McCarthy went to Robert Coleman, then-chairman of U.Va.'s physics department. "He gave me $18,000 to hire a post-doc who could investigate the accelerator idea," says McCarthy. This was the first of many shows of support that McCarthy received from U.Va. faculty and administrators, without which, he says, CEBAF could not have been built. McCarthy sent research associate Blaine Norum (now a professor in U.Va.'s physics department) out to Stanford's physics elite "to pick their brains about how to build an electron accelerator." It soon became clear, according to McCarthy, that the project could not advance without significant monetary support from a variety of sources. Fortunately, the U.Va. president at the time, Frank Hereford, was enthusiastic about the idea of an electron accelerator, perhaps because he himself was a physicist. McCarthy also got valuable backing from U.Va. dean of the Graduate School of Arts and Sciences (and fellow nuclear physicist) Dexter Whitehead. McCarthy knew, however, that he would have to go beyond the Grounds to gather the clout needed to make a proposal to the U.S. Department of Energy (DOE) for major funds. Thus was born the Southeastern Universities Research Association (SURA). At first this consortium included the College of William & Mary, Virginia State University and U.Va. The group soon grew to 13 universities -- each of which anted up $5,000--thanks in part to McCarthy's diplomatic skills. As he remembers it, he used long-time rivalries to influence some of the new members. "I told Duke that North Carolina was joining, then I went to North Carolina and told them Duke was joining," he says. "They both were afraid to miss the opportunity, so they both signed up." Virginia state officials were also early supporters, McCarthy notes. Both then-Gov. Charles S. Robb and then-State Secretary of Education John T. Casteen III (now president of U.Va.) came on board quickly. In 1982, with significant financial backing in place and technical design work well advanced, SURA presented a proposal for an electron accelerator to the Nuclear Science Advisory Committee, a body which advises the National Science Foundation and DOE. Despite being the David among the Goliaths of other competitors, SURA's proposal won. "Argonne Lab and MIT were pretty upset," recalls McCarthy. McCarthy had always hoped the accelerator would be built in Charlottesville, but the nod went to Newport News and construction began there in 1987, under the guidance of Hermann Grunder, who had been named director of CEBAF in 1985. The original proposal was technically quite conservative. "In fact," McCarthy says, "that's one of the reasons our proposal succeeded." By the mid-1980's, though, superconducting technology had advanced sufficiently for Grunder to alter the design to use superconducting radiofrequency (SRF). SRF employs material (a metal called niobium) which, when cooled to extremely low temperatures by liquid helium, loses almost all electrical resistance. Electrons can be accelerated through the niobium chambers nearly to the speed of light without radiating the bulk of the energy in the form of heat. This allows the electron beam to be continuous, rather than pulsed as in earlier accelerators. A pulsing beam causes the electrons to bunch up, leading to thousands of collisions with the target material and presenting researchers with a very confusing picture of the interactions between the electrons and the target atoms. A continuous beam, in contrast, yields a steady flow of collisions and both the electrons and the nuclei with which they interact are therefore easier to analyze. The first test beam was sent through CEBAF in 1994 and the first nuclear physics experiment took place in 1995. The electron beam's journey begins when an electron gun (similar to the device used to project the picture in a television) injects the stream into the first of more than 300 niobium accelerator cavities. As the beam travels around the 7/8 mile oval track, powerful electric fields generated by radio-frequency waves inside the cavities drive the beam to greater speeds and higher energies. After five laps (and four millionths of a second), the electrons are traveling at 99.999999978 percent the speed of light and with an energy of four billion electron volts. But their speed is not what makes them special. Rather, this close approach to the speed of light means the electrons are bound by the rules of relativity as set forth in Einstein's famous equation, E=mc2. In other words, energy and mass become interchangeable. At the end of their journey, electrons are 8,000 times more massive than when they began. This increase in mass is what makes collisions with the target nuclei (each only a trillionth of an inch across) statistically likely. The subatomic realm is not only that of the vanishingly tiny, however, it is also the realm of the truly ancient. Theorists believe that protons were formed in the first 10 millionths of a second following the Big Bang, the primal explosion that created the universe. Thus, when scientists use CEBAF to see inside the proton, they are, in effect, recreating conditions that existed 10 billion or more years ago as the cosmos was being formed. As for the impertinent question, "what is CEBAF good for?" McCarthy answers: "although we cannot say now what practical benefits this basic research might ultimately have, history shows that every investment in pure science has had payoffs that were unexpected and often revolutionary." McCarthy's involvement with CEBAF is by no means ended. His research on proton 'spin' (conducted with undergraduate and graduate student collaborators) will get a boost from the availability of CEBAF. As the grand opening approaches, McCarthy says, "I've been through so many ups and downs with this over the years, I can hardly believe it's finally finished. There were times we could have lost it all. That we made it this far is a testament to good decision-making as well as a bit of luck." ### May 14, 1996 REPORTERS AND EDITORS: For more information about the May 24 opening of CEBAF, contact Linda Ware in Newport News at (804) 249-7100. To arrange interviews with James McCarthy, contact him by phone at (804) 924-6783 or by e-mail at jsm8p@virginia.edu. For more information on SURA, contact the Washington, D.C. office at (202) 347-2810. Television reporters should contact our TV News Office at (804) 924 7550.