 |
 |
Frank Crawford in 1975 with the corrugahorn he invented. |
Physicist Frank Crawford, who worked on bubble chambers, supernovas and adaptive optics, has died at 79
BERKELEY – Frank Stevens Crawford Jr., a consummate physicist who was as intrigued by the physics of hot chocolate as by the workings of atom smashers and supernovas, died July 28 at the age of 79.
Crawford, a professor emeritus of physics at the University of California, Berkeley, and a research scientist at Lawrence Berkeley National Laboratory (LBNL), had suffered from Parkinson's disease for more than 10 years, and died of respiratory failure related to the disease at a board and care home in San Rafael, Calif.
"Frank was a physicist who loved physics so much that he shared his joy with anyone who was around," said Richard Muller, UC Berkeley professor of physics, LBNL physicist and Crawford's colleague for 15 years. "He would share this by noticing the physics of everyday life, but at the same time he could operate at the most sophisticated levels."
Crawford, who retired in 1991, was one of the physicists who designed and engineered the liquid hydrogen bubble chamber, a detector that allowed scientists to see and photograph the interaction of particles produced by cyclotrons and other particle accelerators. The work led to a Nobel Prize in physics for UC Berkeley team leader Luis W. Alvarez in 1968, and produced a flurry of new discoveries in the 1960s and 1970s that created a zoo of new particles and so-called "resonances."
"When Luis invented the liquid hydrogen bubble chamber, that's what led to the enormous breakthrough in discoveries of all these many sub-nuclear particles, the so-called resonances - a large number of them discovered by the Alvarez team," Muller said. "This was the most exciting thing going on in elementary particle physics in the 1960s, and the Alvarez team was way ahead of everybody else."
Crawford's real love, however, was optics and waves, said Arthur Rosenfeld, a commissioner with the California Energy Commission who first met Crawford when he joined the Alvarez group in 1955. Combining this interest with his love of music, Crawford invented in the 1970s a wind instrument he dubbed a "corrugohorn" - a length of flexible corrugated brass pipe that he turned into three basic horns: a bugle, a neck horn and a slide corrugohorn. He would hang out on Telegraph Avenue near the campus playing his corrugohorn for admiring audiences and obtained a vendor's license to sell it there. Crawford built numerous acoustic and optical exhibits that for many years were displayed in the corridors of the physics department.
In the late 1970s, he joined Muller's team to study supernovas and helped set up the first automated supernova search at UC Berkeley's Leuschner Observatory in Lafayette, Calif. In 1986, he found the team's first supernova an unprecedented nine days after the star's explosion. This accomplishment led directly to today's automated supernova searches, which snag scores of supernovas each year, often only hours after the light reaches Earth.
He also conducted early work on adaptive optics, the so-called "rubber mirrors" that flex to remove the twinkle from stars, and built models that proved the concept works.
Beginning in the 1970s, he published a record 47 papers in the American Journal of Physics, many of them delving into the physics of mundane phenomena, such as the sound made by hot chocolate or a child's Slinky, or speculating on issues such as whether pterosaurs could fly because the air density was greater long ago.
"His papers were always charming and a delight to read," Muller said.
Crawford was born Oct. 25, 1923, in Scranton, Penn., and had barely begun his music studies at Phoenix Junior College in Arizona when he was called into the U.S. Air Force in 1943 to serve as a radio operator aboard a B-17 bomber during World War II. Based in Italy, he was shot down over Yugoslavia, where he and the crew were rescued by the Chetnik underground and returned to Allied territory.
After the war, he applied and was accepted in 1946 to UC Berkeley, where he completed his A.B. in physics in 1948 and his Ph.D. in 1953 under Alvarez. According to Alvarez' account, when he returned to UC Berkeley from the Manhattan Project, he felt he had been away from research too long, so he made an agreement with Crawford and fellow graduate student Lynn Stevenson: He would be their thesis advisor if they would teach him modern nuclear physics and quantum mechanics.
Initially, the collaboration involved new accelerator design, but after the invention of the bubble chamber in 1952 - by Donald Glaser, who later came to UC Berkeley and won a Nobel Prize for the work in 1960 - Alvarez steered the group toward bubble chamber design. His major advance, for which he won the Nobel Prize, was to replace the superheated ether of Glaser's chamber with liquid hydrogen. Liquid hydrogen turned out to be a perfect detector for sub-nuclear particles, allowing his group to investigate many types of nuclear reactions. Crawford, who concentrated more on the optical challenges of photographing particle interactions inside the bubble chamber and reconstructing trajectories from the photos, co-authored 23 papers in Physical Review Letters on new particles such as the tau and lambda and the K and pi mesons.
"He was an important member of the team that helped win Luis the Nobel Prize," Muller said, noting that Crawford and his wife accompanied Alvarez to Stockholm for the Nobel ceremony.
Interestingly, Crawford, Alvarez and Stevenson discovered real "cold fusion" in the hydrogen bubble chamber. They found that muons, a particle produced in abundance by cosmic rays, catalyzed hydrogen fusion at a very low rate at room-temperature. The team thoroughly characterized these reactions, Muller said, but this reaction clearly was not a practical way to obtain fusion energy and had nothing in common with the farcical cold fusion hyped in the 1990s.
Crawford joined the UC Berkeley physics department in 1958, though he continued his work at LBNL.
Crawford played many instruments, ranging from the flute, clarinet and saxophone to the piano, and always had a tune in his head, Muller said. In the 1970s he began teaching acoustics classes, including a course on the physics of music, and invented the corrugohorn after he got intrigued by a child's toy that hummed when twirled. The toy, called a Hummer, was a yard-long piece of corrugated plastic pipe, and by experimenting, he discovered that a smaller, flexible gas pipe could be played by blowing.
"One day I put a brass tube in my mouth and found I was playing bugle sounds with very little effort and beautiful tone," he was quoted as saying in a campus press release in 1975. "Soon I got longer brass tubes and found I could play very nice 12-bar blues."
Drawing upon his interest in acoustics, he wrote an introductory book called "Waves," published in 1968 as Vol. 3 of the Berkeley Physics Course, that included a kit to do home experiments. The book, part of a series aimed at making physics more lively and relevant, is still in use in college classrooms around the world, and is considered one of the best, though not easiest, introductions to waves and vibrations.
In 1977, he began work on a new concept for making ground-based telescopes see more clearly. Dubbed the rubber mirror, it involved flexing a telescope's mirror to counter the movement of an image caused by turbulence in the atmosphere. He built a working model that used a bright laser as a comparison light, Rosenfeld said, but the technology to make this work with faint starlight did not come along for another 20 years.
Crawford was a member of the American Physical Society, Sigma Xi, the American Association of Physics Teachers and the Italian Physical Society.
Upon retirement, he switched fields again to general relativity, working on cosmological questions such as what came before the Big Bang that supposedly created the universe.
"Frank exhibited a love of physics in all of its aspects, a willingness to plunge into any field of science that intrigued him - and nearly every one did," Muller said. "That is certainly what I found most wonderful about Frank."
"He was generous, funny and brilliant," said his wife, Elizabeth Crawford, of Berkeley.
He is survived by his wife, Elizabeth; his ex-wife, Bevalyn Crawford, of Petaluma, Calif.; two children by Bevalyn - Sarah Teal Crawford of the Washington, D.C., area and Matthew Crawford of Richmond, Va. - and by his sister, Frances.
A memorial service was held on Aug. 2 in the UC Berkeley Faculty Club.
Donations in his memory may be made to The Jazzschool, 2087 Addison St., Berkeley, CA 94704 (http://www.jazzschool.com/).