About Julius Ashkin

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Dr. Julius Ashkin was a professor of physics at Carnegie Mellon University, and served as department chairman from 1961 to 1972. He had an unusually broad impact on scientific knowledge, with major contributions in nuclear physics, elementary particle physics, statistical mechanics, and experimental solid state physics. He was an able administrator, who guided the Physics Department through an important period of renewal and growth. He was an outstanding teacher, who left a rich legacy with his many students.

Dr. Ashkin was born in Brooklyn in 1920 and received his Ph.D. from Columbia University in 1943. Even before his Ph.D. research was completed, Ashkin started working on the Manhattan project, first in Chicago and, from 1943 to 1946, at Los Alamos. In 1946, Robert Marshak brought him to the University of Rochester, where he served as assistant professor for four years. In 1950, he joined the faculty of Carnegie Institute of Technology (now Carnegie Mellon University).

At Columbia, Dr. Ashkin worked with Edward Teller on an extension of the Ising model, now widely known as the Ashkin-Teller model, which has highly unusual, non-universal properties. His thesis work, carried out with Willis Lamb, concerned the propagation of order in crystal lattices. After the war, he collaborated with Hans Bethe on a major review of the theoretical and experimental knowledge of the energy loss of particles and radiation passing through matter. Published as a chapter of Experimental Nuclear Physics, edited by Emilio Segre, this review served for many years as a standard reference for experimentalists in nuclear and particle physics. Together with T. Y. Wu, Dr. Ashkin carried out one of the first detailed calculations of nucleon-nucleon scattering. Later, he pointed out that the equality of the polarization and asymmetry parameters in that scattering was not obvious, and in a 1952 paper with Lincoln Wolfenstein showed that this equality was a test of time-reversal invariance.

Progress in theoretical particle physics was very slow in the early 1950s, and it was clear that more experiments were needed. Therefore, Dr. Ashkin converted himself to an experimental physicist to take advantage of the newly completed Carnegie Tech synchrocyclotron in Saxonburg, Pennsylvania. He embarked on a series of careful measurements of the scattering of positive and negative pions from hydrogen and deuterium. The results, reported in 1954, following earlier experiments by Enrico Fermi's group at Chicago, showed clearly that the scattering could be explained by a resonance with spin 3/2 and isotopic spin 3/2. This was the first and the most important of the many resonance's that led to the present-day quark model.

In 1958, while on a sabbatical, Dr. Ashkin joined a group carrying out the first experiment at the CERN sychrocyclotron. He played a key role in the discovery of the rare decay which provided an essential confirmation of the theory of weak interactions.

Dr. Ashkin died on June 4, 1982, after a lengthy illness.

He will be remembered for his important contributions to statistical mechanics, nuclear physics, and elementary particle physics.

He will be remembered as a superb teacher to a generation of undergraduates, graduate students and research workers. He had such an appreciation of the beauty, simplicity, and deep connectedness of physics that his enthusiasm for the subject was naturally transmitted to his students.

His memory will continue to be honored in the yearly Julius Ashkin Teaching Award in the Mellon College of Science.