Benjamin Lax

Benjamin Lax, pioneering solid-sate and plasma physicist, MIT Professor of Physics and long-time Director of the MIT National Magnet Laboratory, died at age 99 on April 21, 2015 in Newton, MA.

Benjamin Lax was born on December 29, 1915 in Miskolc, Hungary. He moved with his family to the United Sates in 1926, settling in Brooklyn, New York. After completing Boys High School in Brooklyn, he graduated cum laude from Cooper Union in 1941 with a degree in mechanical engineering. His ambition to do graduate work in mathematics at Brown University was interrupted by his being drafted into the US Army in 1942. He was assigned to the famous MIT Radiation Laboratory where he worked on a crash program to develop a new radar system “Little Abner” which was successfully tested in the field. After the War, Ben completed a Ph. D. degree in physics at MIT in 1949. His thesis on “The effect of magnetic field on the breakdown of gases at high frequencies,” utilized cyclotron resonance, a topic that he would continue to pursue in solid-state and plasma physics throughout his career.

In 1951, Ben joined the MIT Lincoln Laboratory, where he made major contributions to the understanding of semiconductors, particularly through studies of their energy band structure using cyclotron resonance. Cyclotron resonance absorption of microwave radiation was used to measure the effective mass of electrons which was determined by the curve of the energy bands. These studies of germanium and silicon by Ben and his co-workers were particularly important, since these materials were crucial to the progress of semiconductor devices. Ben was also a co-inventor on an early patent for the semiconductor laser. Ben was recognized by Lincoln Laboratory for both his scientific advances and his abilities as a leader and he was promoted to Head of the Solid-State Division in 1958 and Associate Director of the Laboratory in 1964. In 1960, he was recognized by the APS as the recipient of the Oliver E. Buckley Condensed Matter Physics Prize “For his fundamental contributions in microwave and infrared spectroscopy of semiconductors.”

In the late 1950s, while still working at MIT Lincoln Laboratory, he led a group of scientists and engineers who proposed a high magnetic field laboratory on the MIT campus for research in solid state physics, plasma physics, magnetic resonance spectroscopy and magnet engineering. The proposal was accepted, the National Magnet Laboratory was established in 1960, and Ben served as its Director for its first 21 years. Ben also accepted a position as a Professor in the MIT Physics Department in 1964.

While Ben served as Director, the National Magnet Laboratory (NML) became an international leader in a remarkably wide range of research areas including the physics of solids in high magnetic fields; high magnetic field nuclear magnetic resonance (NMR); pioneering work on biomagnetism; a range of applications of magnet technology including magnetic levitation for trains; laser- plasma interactions in high magnetic fields and laser plasma diagnostics. He was also interested in the use of high magnetic fields to achieve better confinement of plasmas for fusion. The first high magnetic field tokamak confinement device, Alcator, was constructed and operated at the NML, successfully demonstrating the benefits of the high magnetic field approach. Eventually, the research on plasma physics and fusion energy required larger facilities, leading to the establishment of the MIT Plasma Fusion Center adjacent to the NML.

Ben was also active in teaching and in training PhD students. He supervised the Ph. D. theses of 36 students at MIT, many of whom went on to highly successful careers in physics and engineering. He was a mentor to many young research scientists who gained valuable experience conducting research at the NML. He retired from the directorship of the Francis Bitter National Magnet Laboratory in 1981 and from the physics faculty in 1986. After his retirement, Ben stayed active in physics for more than 15 years, including being a consultant at the MIT Lincoln Laboratory. He was the co-author of a classic book on “Microwave Ferrites and Ferrimagnetics,” and the author / co-author of over 300 journal articles and book chapters. Among many honors, he was elected to the National Academy of Sciences in 1969 and was a Fellow of the American Physical Society and of the AAAS.

Ben was also a talented athlete, a gymnast in his youth, who began skiing at the age of 50. He brought to the athletic field the same intensity and enthusiasm as he conveyed in the laboratory. He was a wonderful mentor to countless students, young scientists and colleagues. His brilliance, his boundless energy and his enthusiasm for physics will be greatly missed.

Daniel Cohn
Richard Temkin
MIT
Cambridge, MA

Photo Credit: Bachrach Photography

Professor Emeritus Benjamin Lax dies at 99
MIT News, Massachusetts Institute of Technology