Maurice M. Shapiro, an outstanding scientist and educator whose contributions spanned a range of fields, died on 27 February 2008 in Alexandria, Virginia.
Maury was born in Jerusalem on 13 November 1915 to J. Simon Werner and Miriam Rivka. His father never returned home from World War I, and his mother married Rabbi Osher Shapiro, a US citizen, two years later. They migrated to Chicago in the early 1920s. His parents had planned a theological career for him, but he opted to study physics at the University of Chicago. Under Arthur Compton, he received his PhD in 1942; he used early emulsions—both on glass plates and stripped—exposed at Mount Evans, Colorado, to study cosmic-ray-induced collisions, which produced starlike images in photo emulsions. He wrote definitive reviews in 1941 in Reviews of Modern Physics on the emulsion technique in the use of high-density visual detectors and a 1958 article entitled “Emulsions” in Handbuch der Physik.
During World War II, Maury led the water effects group, which studied underwater explosions for the Manhattan Project’s Los Alamos ordnance division. He witnessed the Trinity test and there “shared a blanket” with Hans Bethe, as he wrote in a 1993 article. Because he understood the nature of the new weapons, Maury helped form the Association of Los Alamos Scientists to lobby for a civilian atomic energy commission; he served as ALAS chair in 1946. Just after the war, he worked at Oak Ridge National Laboratory on the design of a power reactor similar to that used in naval vessels. In 1949 he joined the Naval Research Laboratory (NRL) and went to work in its nuclear physics division. There he started a new program in high-energy physics and cosmic rays and conducted many experimental investigations related to cosmic rays and particle properties. Using the emulsion chamber technique and high-altitude exposures, Maury measured and verified the saturation of relativistic rise in ionization. He also measured helium and proton flux at high rigidity, secondary-to-primary ratios (lithium, beryllium, and boron to carbon, nitrogen, and oxygen), properties of heavy baryons, and, with his colleagues, the neutral pion lifetime.
Maury’s main interests were in understanding the origin, acceleration, and propagation of cosmic rays and in the role of high-energy neutrinos and their detection; he also played a major role in the birth of high-energy neutrino astronomy. My association with him started when I joined the University of Maryland’s high-energy group in 1961. Maury had an NRL group working in particle physics and cosmic rays using nuclear emulsions and was starting a bubble chamber group, whose members included Bernard Hildebrand, Bert Stiller, Rein Silberberg, C. H. Tsao, and Robert Glasser. Maryland’s high-energy group led by George Snow and the NRL particle-physics group interacted because both were studying properties of high-energy particles with nuclear emulsions and bubble chambers. I was a consultant with the NRL group for some 10 years.
In the 1960s Maury investigated the ramifications and limitations of supernova theories for the origin of cosmic rays and studied the production of high-energy neutrinos and gamma rays from those sources. He was a member of the DUMAND project, which studied high-energy neutrinos, throughout the project’s lifetime, from 1976 to 1995. With Silberberg, he examined the sensitivity of DUMAND to study high-energy astrophysical neutrinos and their sources.
Maury’s cosmic-ray group at the NRL made seminal contributions in quantitatively exploring isotope ratios—using isotopes to determine the time lag between explosion and acceleration in supernova sources. Those results suggested the importance of the first ionization potential in injection, provided detailed analysis of the so-called slab model, and showed reacceleration of cosmic rays.
In 1977 Maury founded the International School of Cosmic Ray Astrophysics in Erice, Italy; he was the school’s director until his death. Many outstanding scientists in the field attended the school at early stages of their careers. When he retired from the NRL, he was still active in research and was interested in having a US base of operations for the school. He approached me about whether the University of Maryland would be a possibility. I was delighted and suggested a visiting professorship so he could continue his work without having to move out of the Washington, DC, area. Thus began his association with the university, a relationship that continued until his death. He was still swimming in the Mediterranean during the school sessions at Erice four years before his passing.
Maury was a true gentleman and a good friend. His warmth and kindness were quite infectious. An ambassador for the field of cosmic rays, he contributed to both experimental and theoretical investigations of them and of their central role in connecting many diverse disciplines in particle physics, astrophysics, geophysics, and acoustical physics. Maury was an outstanding scientist and was greatly concerned about world peace and human affairs.