Ralph P. Shutt, a leader in experimental particle physics at Brookhaven National Laboratory (BNL) for many years, died on 2 February 2001 in a hospital in Pt. Jefferson, New York. He had been in poor health after suffering a series of small strokes over the previous few years.
Shutt was born in St. Moritz, Switzerland, on 7 December 1913. He grew up and was educated in Berlin, receiving his BS in physics from the Technical University of Berlin in 1935. For a time, he was employed in engineering by the Siemens Co, but returned to school and received his doctorate of science in physics in 1938 from the Technical University of Berlin. His early work on cloud chambers won him a prize in recognition of his technical contributions to this new technique. He also trained as a classical pianist and faced a difficult career choice before deciding on a life in science.
Because of the threat of persecution due to his partial Jewish ancestry, Shutt left Germany and immigrated to the US in 1939. From 1939 to 1946, he worked at the Bartol Research Foundation of the Franklin Institute in Swarthmore, Pennsylvania, doing research on cosmic radiation using cloud chambers and war research on acoustics and ultrasonics. He also taught physics at Swarthmore College. From 1946 to 1947, he worked at the Aberdeen Proving Ground in Maryland, conducting research on cosmic radiation using high-pressure cloud chambers.
Shortly after its establishment in 1947, Shutt joined the new BNL to lead the design, building, and use, initially, of cloud chambers and then of bubble chambers, first at the Cosmotron and then at the Alternating Gradient Synchrotron (AGS). In 1953, Shutt and his colleagues were the first to verify the paired production of so-called strange particles and, therefore, the existence of strangeness. In their experiment, they used a high-pressure hydrogen diffusion cloud chamber, a new device for which the theory was developed by Shutt. The device was continuously sensitive, with no dead time, and therefore well matched to an accelerator with a one-second repetition rate. The chamber was placed in an 11-kilogauss magnetic field and exposed to a beam of 1.5-GeV π − mesons produced by a 2.2-GeV proton beam in the Cosmotron. This discovery that the strange particles were produced in pairs in “associated production” was a first essential step on the road that led to the description of matter as constituted by quarks.
At the AGS, Shutt led the effort to exploit the physics potential of this new machine with bubble chambers. From 1958 to 1975, a series of ever larger and more productive bubble chambers were built, known as the 20-inch, 31-inch, 80-inch, and 7-foot chambers. More than 37 million pictures for the study of elementary particle physics were produced by these chambers. Their construction and safe operation were noteworthy accomplishments, requiring a staff of creative and competent physicists, engineers, and support personnel to invent and develop many new techniques and technical devices.
For the use of the chambers, beginning with the 20-inch chamber, Shutt pioneered a unique user mode that benefited a wide community of physicists. This mode was made possible by both Shutt’s strong desire to share the benefits of this experimental technique and by the usefulness of photographic film as a viable distribution medium. Users from universities and laboratories worldwide proposed and received approval for a variety of experiments using beams of pions, kaons, protons, antiprotons, and neutrinos at a variety of energies and with various bubble chamber liquids. Some 75% of the resulting film was distributed by BNL to these outside users. The remaining 25% was retained by the BNL groups that were responsible for building and maintaining the experimental equipment. This scheme bolstered productivity and resulted in a large physics output. Results included the discovery of a host of particles and resonances, among the more noteworthy being the ϕ, ρ, f0, η’, f’, , Ξ⊛, and the Ω−, Σc++, and λc+. These resonances and the accompanying dynamical studies provided much of the data that led to the establishment of the now accepted standard model of particle physics.
In the 1970s, as electronic detectors gained prominence as particle accelerators, Shutt supported and encouraged their development, recognizing them as the natural evolution in detector technology. During this period, he collaborated on the design and construction of a cold-neutron spectrometer for the high-flux beam reactor at BNL. In 1980, he joined Robert Palmer and colleagues to develop an alternative superconducting magnet for the proposed Isabelle accelerator. The magnet proved successful and was the basis for the revised Isabelle, renamed the Colliding Beam Accelerator (CBA), in 1981. This project, however, was canceled by the US Department of Energy (DOE) in 1982 in favor of a much larger machine, the Superconducting Super Collider, for which BNL designed and built prototype superconducting dipole magnets in collaboration with the SSC central design group and the staff at Lawrence Berkeley National Laboratory in California and at Fermi National Accelerator Laboratory in Illinois. Some years later, the completed CBA infrastructure at BNL was adapted for BNL’s now completed Relativistic Heavy Ion Collider, a machine for heavy-ion physics, built with superconducting magnets, and sponsored by the DOE’s nuclear physics program.
Shutt contributed to all these projects in manifold ways. In particular, he focused on the thermodynamics of magnet cooling and heating, quench pressure buildup questions, stress analysis of magnet structures, analysis of bellows stability, and power lead designs. He invented the concept of cross-flow cooling for SSC magnets, which allowed the superconducting coils in those long magnets to remain adequately cool in the face of eddy-current and beam-energy-deposit heating. The stresses in metal bellows attracted his interest. With insightful analysis, he developed new and detailed formulas for their safe use. His designs for power-lead construction have been proven correct and efficient in practice. Shutt’s thorough grounding in classical mathematics, especially in the use of partial differential equations, which he received in his early schooling in Germany, made it possible for him to do many of these calculations. In a related effort in the late 1980s, he took an active part in the design and analysis of the large superconducting magnet for the muon (g − 2) experiment that is currently under way at BNL (see Physics Today, Physics Today 0031-9228 54 4 2001 18 https://doi.org/10.1063/1.1372101 April 2001, page 18 ).
During his years at BNL, Shutt held various administrative posts, including bubble chamber group leader, from the first use of bubble chambers in the 1950s through 1971; deputy chairman of the accelerator department (1971-73); deputy chairman of the physics department (1974–75); and head of the superconducting magnet division (1982–84). And, in 1993, the American Physical Society awarded Shutt and his colleagues Nicholas Samios and Robert Palmer the 1993 W. K. H. Panofsky Prize for their discovery of the Ω− hyperon.
But Shutt’s preference was to be involved in projects at a technical level and to analyze and understand through calculations the thermodynamic performance of a device, or the forces in structures, and the limits they impose. He was technically demanding, and he was at his best in detecting subtle flaws in complicated designs and suggesting remedies that were at once comprehensive and practical.
Shutt was a shy person, preferring one-on-one or small group interactions. There his friendliness, natural wit, and perceptive nature were evident and engaging. He was generous with his time and knowledge in the mentoring of younger colleagues, continuing his valuable contributions in this way until a few years before his death. Perhaps his greatest strength was that he recognized talent and competence, and encouraged and made possible the start of many successful professional careers over the years. This generosity of spirit will be a lasting tribute to the memory of Ralph Shutt.
