Obituary of Marshall Fox Crouch

Marshall Fox Crouch, who was a professor of physics at Case Western Reserve University for thirty‑five years, died at his home in Ohio on February 18, 2009. Crouch was a pioneer in the detection, identification and interactions of cosmic rays.

Marshall was born in St. Louis in 1920. After completing his bachelor’s degree at the University of Michigan in 1941, Marshall worked at MIT and Los Alamos, specializing in electronics associated with radar. He joined the US Army in 1943 and spent three years working in communications in New Guinea, Manila, and after the war, at US bases in Japan. Marshall completed his PhD at Washington University, St. Louis, under the guidance of Robert Sard. After joining the department at Case Institute of Technology (a precursor of CWRU) in 1952, he continued to collaborate with Sard on the capture of negative cosmic muons by nuclei. At Case, Crouch and his grad students studied the moderation of fast neutrons in water.

The cosmic ray effort at Case expanded in the mid‑1950’s with the arrival of Fred Reines, who took over as chair, and Glen Frye and Tom Jenkins. Crouch, Jenkins and Reines, along with a team of post‑docs, techs, and grad students, travelled to South Africa to collaborate with the University of Witwatersrand on the installation of a major muon detector in a 10,500 foot deep gold mine. By measuring the incoming muon flux as a function of direction, and consequently as a function of depth of penetration, they were able to show, in a 1965 publication, that the muons were produced in the earth, presumably by cosmic neutrinos. This was the first observation of “natural” neutrinos, i.e. not “man‑made” neutrinos at a reactor. Over the course of the next ten years, Crouch continued to collaborate with Reines, though the latter had moved on to a deanship at UC Irvine. Together, they were able to extract additional significant information from the gold‑mine data: specifically limits on the proton lifetime and cross sections for weak interactions.

Starting with his posting in Japan as a young soldier, Crouch became fascinated with the Japanese people and culture. Between 1956 and 1978, he and his family traveled to Japan on four occasions to spend a year or two, first on a Fulbright Scholarship, then as Deputy Scientific Attache at the US Embassy, then twice as a visiting professor at the University of Tokyo. Back home in Cleveland, Marshall took part in the Irvine Michigan Brookhaven Collaboration which set up detectors to search for proton decay and cosmic neutrinos. This time, the locale was a saltmine, only a few miles from Crouch’s home in Ohio. He retired from CWRU in 1987, while continuing for several years more as part of the IMB experiment. He is survived by his wife of 60 years, Katherine, and by three sons, a daughter, and five grandchildren. Marshall was a soft‑spoken and gracious colleague and an invaluable and important asset to the physics teaching and research programs at CWRU.