BURTON RICHTER

NOBEL PRIZE IN PHYSICS, 1976

I was born on 22 March 1931 in New York, the elder child of Abraham and Fanny Richter. In 1948 I entered the Massachusetts Institute of Technology, undecided between studies of chemistry and physics, but my first year convinced me that physics was more interesting to me. The most influential teacher in my undergraduate years was Professor Francis Friedman, who opened my eyes to the beauty of physics. 

In the summer following my junior year, I began work with Professor Francis Bitter in MIT's magnet laboratory. During that summer I had my introduction to the electron-positron system, working part-time with Professor Martin Deutsch, who was conducting his classical positronium experiments using a large magnet in Bitter's laboratory. Under Bitter's direction, I completed my senior thesis on the quadratic Zeeman effect in hydrogen. 

I entered graduate school at MIT in 1952, continuing to work with Bitter and his group. During my first year as a graduate student, we worked on a measurement of the isotope shift and hyperfine structure of mercury isotopes. My job was to make the relatively short-lived mercury-197 isotope by using the MIT cyclotron to bombard gold with a deuteron beam. By the end of the year I found myself more interested in the nuclear- and particlephysics problems to which I had been exposed and in the accelerator I had used, than in the main theme of the experiment. I arranged to spend six months at the Brookhaven National Laboratory's 3-GeV proton accelerator to see if particle physics was really what I wanted to do. It was, and I returned to the MIT synchrotron laboratory. This small machine was a magnificent training ground for students, for not only did we have to design and build the apparatus required for our experiments, but we also had to help maintain and operate the accelerator. My Ph.D. thesis was completed on the photoproduction of pi-mesons from hydrogen, under the direction of Dr. L. S. Osborne, in 1956. 

During my years at the synchrotron laboratory, I had become interested in the theory of quantum electrodynamics and had decided that what I would most like to do after completing my dissertation work was to probe the short-distance behavior of the electromagnetic interaction. So I sought a job at Stanford's High-Energy Physics Laboratory where there was a 700 MeV electron linear accelerator. My first experiment there, the study of electron-positron pairs by gamma-rays, established that quantum electrodynamics was correct to distances as small as about 10-13 cm. 

In 1960, I married Laurose Becker. We have two children, Elizabeth, born in 1961, and Matthew, born in 1963. 

In 1957, G. K O'Neill of Princeton had proposed building a colliding beam machine that would use the HEPL linac as an injector, and allow electron-electron scattering to be studied at a canter-of-mass energy ten times larger than my pair experiment. I joined O'Neill and with W. C. Barber and B. Gittelman we began to build the first colliding beam device. It took us about six years to make the beams behave properly. This device was the ancestor of all of the colliding beam storage rings to follow. The technique has been so productive that all high-energy physics accelerators now being developed are colliding beam devices. 

In 1965, after we had finally made a very complicated accelerator work and had built the needed experimental apparatus, the experiment was carried out, with the result that the validity of quantum electrodynamics was extended down to less than 10-14 cm. 

Even before the ring at HEPL was operating, I had begun to think about a high-energy electron-positron colliding-beam machine and what one could do with it. In particular, I wanted to study the structure of the strongly interacting particles. I had moved to SLAC in 1963, and with the encouragement of W. K. H. Panofsky, the SLAC Director, I set up a group to make a final design of a high-energy electron-positron machine. We completed a preliminary design in 1964 and in 1965 submitted a request for funds to the Atomic Energy Commission. That was the beginning of a long struggle to obtain funding for the device, during which I made some excursions into other experiments. My group designed and built part of the large magnetic spectrometer complex at SLAC and used it to do a series of pi- and K-meson photoproduction experiments. Throughout this time, however, I kept pushing for the storage ring and kept the design group alive. Finally, in 1970, we received funds to begin building the storage ring (now called SPEAR) as well as a large magnetic detector that we had designed for the first set of experiments. In 1973 the experiments finally began, and the results were all that I had hoped for. The discovery for which I have been honored with the Nobel Prize and the experiments that elucidated exactly what that discovery implied are described in the accompanying lecture. Much more has been done with the SPEAR storage ring, but that is another story. 

I spent the academic year, 1975-76, on sabbatical leave at CERN, Geneva. During that year I began an experiment on the ISR, the (CERN 30 by 30 GeV proton storage rings, and worked out the general energy scaling laws for high-energy electron-positron colliding-beam storage rings. My motive for this last work was two-fold - to solve the general problems and to look specifically at the parameters of a collider in the 100-200 GeV c.m. energy range that would, I thought, be required to better understand the weak interaction and its relation to the electromagnetic interaction. That study turned into the first-order design of the 27 km circumference LEP project at CERN that was so brilliantly brought into being by the CERN staff in the l980's. 

An interesting sidelight to the LEP story is the attempt by Professor Guy von Dardel of Lund and Chairman of the European Committee for Future Accelerators and I to turn LEP into an inter-regional project. We failed because we couldn't interest either the American or European high-energy physics communities in a collaboration even on as large a scale as LEP. The time was not right, but it surely must be sooner or later. 

The general scaling laws for storage rings showed that the size and cost of such machines increased as the square of the energy. LEP, though very large, was financially feasible, but a machine of ten times the energy of LEP would not be. I began to think about alternative approaches with more favorable scaling laws and soon focused on the idea of the linear collider where electron and positron beams from separate linear accelerators were fired at each other to produce the high-energy interactions. The key to achieving sufficient reaction rate to allow interesting physics studies at high energies was to make the beam extremely small at the interaction point, many orders of magnitude less in area than the colliding beams in the storage rings. 

In 1978 I met A. N. Skrinsky of Novosibirsk and Maury Tigner of Cornell at a workshop we were attending on future possibilities for high energy machines. We discovered that we had all been thinking along the same general lines and at that workshop we derived, with the help of others present, the critical equations for the design of linear colliders. On returning from the workshop I got a group of people together at the Stanford Linear Accelerator Center and we began to investigate the possibility of turning the two-mile-long SLAC linac into a linear collider. It would be a hybrid kind of machine, with both electrons and positrons accelerated in the same linear accelerator, and with an array of magnets at the end to separate the two beams and then bring them back into head-on collisions. The beams had to have a radius of approximately two microns at the collision point to get enough events to be interesting as a physics research tool, roughly a factor of 1000 less in area than the colliding beams in a storage ring. Construction of SLAC Linear Collider began in 1983, and was finished in late 1987. The first physics experiments began in 1990. Probably the most lasting contribution that this facility makes to particle physics will be the work on accelerator physics and beam dynamics that has been done with the machine and which forms the basis of very active R&D programs aimed at TeV-scale linear colliders for the future. The R&D program is being pursued in the U.S., Europe, the Soviet Union and Japan. Perhaps this will be the inter-regional machine that von Dardel and I tried to make of LEP in the later 1970's. 

Along the way I succumbed to temptation and became a scientific administrator first as Technical Director of the Stanford Linear Accelerator Center from 1982 to 1984, and then Director from 1984 to the present. The job of a laboratory director is much different from the job of a physicist, particularly in a time of tight budgets. It is much easier to do physics when someone else gets the funds than it is to get the funds for others to do the research. 

Writing this brief biography had made me realize what a long love affiar I have had with the electron. Like most love affairs, it has had its ups and downs, but for me the joys have far outweighed the frustrations.