CONTACT: Dawn Levy, News Service (650) 725-1944; e-mail: email@example.com
EDITORS: Photos of Brown are available on the web at http://newsphotos.stanford.edu/ . Photos courtesy Vera Lüth.
Karl Brown, pioneer of linear accelerators to treat cancer, dies
Karl Leslie Brown, professor emeritus of applied research at the Stanford Linear Accelerator Center (SLAC) and pioneer in the development of linear accelerators for cancer treatment, died of heart failure Aug. 29 at Stanford Hospital. He was 76.
"Karl has made innumerable contributions in many areas to the work of the Hansen Laboratories on the main campus and to SLAC," said SLAC Director Emeritus Wolfgang K. H. Panofsky, a longtime friend and colleague. "He is probably best known internationally for his development of the programs which make it possible to easily trace the path of particles through complex magnetic beam transport systems. However, his contributions go well beyond that and we all are extremely sad about his passing."
Brown was born in Coalville, Utah, on Sept. 30, 1925. His father was a carpenter and part-time farmer, and his mother, a nurse. He attended the University of Utah as an electrical engineering student but in 1946 transferred to Stanford as a senior to work on particle accelerators. This move was the beginning of a Stanford career spanning more than half a century.
He earned B.S. ('47), M.S. ('49) and Ph.D. ('53) degrees in physics from Stanford and served at SLAC as a senior research associate from 1962 to 1974, adjunct professor from 1974 to 1982 and professor since 1983. SLAC has a program to award employees for each decade of service, and Brown was the first recipient of a "50 Year Award." He remained professionally active until his death.
"When I arrived at Stanford University in 1951," Panofsky recalled, "Karl was already there working with Drs. Edward Ginzton and Marvin Chodorow on klystrons [devices that generate and amplify the high-frequency electromagnetic waves required for particle accelerators] and the then nascent Mark III linear accelerator. We have been friends and colleagues ever since." Brown's commissioning of the preceding Mark II accelerator qualified him for his physics doctorate.
Declining offers from prestigious East Coast institutions, Brown decided to pursue his research at Stanford and in 1953 joined the Physics Department's Hansen Laboratories. In the early 1960s, when Panofsky conceived the idea for the Stanford linear accelerator, Brown became a member of the core team of young scientists who designed and built the 2-mile-long accelerator under Panofsky's direction.
In 1958, Brown was the first to use matrix algebra to calculate magnetic-optical aberrations in charged particle spectrometers, used by physicists for the precise analysis of nuclear and subnuclear structure. He developed a computer code called TRANSPORT to facilitate the equipment design process. This code later became a tool used worldwide to design spectrometers, beam lines and accelerators ranging in energies up to 1 million million electron-volts (1 TeV).
Explained SLAC experimental physicist Vera Lüth, Brown's wife of 25 years: "His main contribution was to develop the scientific and mathematical concepts for magnetic-optical systems for charged particle transport and to make them widely accessible for practical use by scientists and engineers."
Brown also introduced the use of sextupole magnets (those having six poles) to enhance the performance of spectrometers in SLAC's End Station, at the terminus of the linear accelerator, where scientists conducted experiments with high-energy electrons hitting stationary atoms. While scientists were colliding beams in circular machines, Brown in the 1960s proposed having two linear accelerators shoot beams at each other. That informal suggestion is now the basis of advanced accelerator planning.
Brown later designed achromatic magnetic optical systems. Such systems can bend beams by the same amount to a very good approximation independent of their energies. His designs made it possible to engineer beams as small as a millionth of a meter (i.e., one micron). They found application in medical diagnosis and treatment, and modifications of his designs are widely used.
Brown's beam work even attracted military interest because of its relevance to Reagan's Star Wars system, Lüth said, and he taught some classes to military scientists. His publication list is relatively short, but it greatly influenced designers of accelerators. Traveling worldwide to assist in design of spectrometers and accelerators, Brown took sabbaticals in 1959 at Orsay in France, from 1972 to 1973 at the European Laboratory for Particle Physics (CERN) and from 1992 to 1994 at the since abandoned Superconducting Super Collider in Texas.
Small linear accelerators to treat cancer
Though Brown was internationally renowned as an expert in beam optics for nuclear spectrometers and high-energy particle accelerators, his greatest satisfaction came from his contributions toward the development of small linear accelerators for radiation therapy. As a graduate student in the 1950s, he was part of a small research team at Stanford that, with applied physics graduate students Arnold Eldredge and Ken Mallory and faculty members Edward Ginzton of the Physics Department and Henry S. Kaplan of the Medical School, designed the first linear accelerator in the United States to be used successfully to treat a cancer patient.
In the late 1960s, Brown initiated and led the development by Varian Associates of the first commercially successful line of such machines, the CLINAC series. The present-day incarnation of CLINAC treats more than 100,000 patients a day worldwide. Brown was president and chief scientist of Spectromagnetics, an accelerator magnet design and manufacturing company that was sold to Varian Associates in 1966. During a hiatus from Stanford from 1966 to 1968, he served at Varian's Radiation Division as senior scientist and director of research, overseeing commercial development of the CLINAC. He continued to consult for Varian since then.
A fellow of the American Physical Society, Brown was awarded the 1989 Prize for Achievement in Accelerator Physics and Technology by the U.S. Particle Accelerator School, a postgraduate training venue for scientists.
"He was a scientist and very much a 'people person,' liked by so many," recalled Lüth. In his spare time, he enjoyed reading nonfiction, science history and world events.
A longtime resident of Menlo Park, Calif., Brown is survived by Lüth, as well as five children from his earlier marriage to Anadel Smith-Law (Stanford Class of 1947) David Brown of Danville, Calif.; Dennistoun Brown of Billings, Mont.; Adriana Cassani of Lindon, Utah; Jeremy Brown of Los Altos, Calif.; and Andrew Brown of Mountain View, Calif. -- and 14 grandchildren. Three of his children -- David, Dennistoun and Jeremy -- are Stanford graduates.
A memorial service will be held Sept. 27 at 10 a.m. at Valley Presbyterian Church, 945 Portola Road, Portola Valley. In lieu of flowers, the family prefers contributions to the Karl L. Brown Memorial Young Scholars Fund or written recollections of favorite memories of Brown. For details, see www.karlbrown.info.
By Dawn Levy