Robert Hofstadter, Electron Scattering,
the Structure of the Nucleons, and Scintillation Counters

Resources with Additional Information · Patents

After receiving a B.S. from The City College of New York in 1935, Robert Hofstadter completed his Ph.D. at Princeton University in 1938.  He worked at the National Bureau of Standards during World War II and afterwards returned to Princeton, where, during the late 1940s, “he began serious studies of nuclear processes and particle detectors. ...


Robert Hofstadter
Courtesy of The City
University of New York

In 1948 he made the important discovery that thallium‐activated sodium iodide, NaI(Tl), made an excellent scintillation counter;  and in 1950 ... he showed how NaI(Tl) could be used as a spectrometer for measuring gamma ray energies. This crucial discovery by Hofstadter has had far‐reaching effects. This material has been in universal use as a gamma ray spectrometer ever since that initial discovery, and has been an important factor in all branches of nuclear and high energy physics, in astrophysics, as well as in medicine, biology, chemistry, geology, and many other fields. In later years, Hofstadter was to look back on his discovery of the linearity of response and high light output of NaI(Tl) as the most important contribution he made to science (in terms of its impact on a variety of fields).”

In 1950, Hofstadter joined the faculty at Stanford where he “immediately embarked on a program of the study of elastic and inelastic scattering of high energy electrons by atomic nuclei. ... These electron scattering studies continued over the next 20 years and elucidated the distribution of electric charge (and the associated magnetism) within atomic nuclei, and particularly in the alpha particle and the proton and the neutron. For the first time, the proton and the neutron were shown to be non‐point particles and therefore possessed structure. For this work Hofstadter was awarded the Nobel Prize in Physics in 1961. ...

In 1970 Hofstadter introduced the idea of a large high energy gamma ray detector which would be located on a satellite in earth orbit; the purpose of such a detector would be to do gamma ray astronomy, then a field in its infancy. Much of Hofstadter’s effort in the last decade was to help design, build and test the EGRET [Energetic Gamma Ray Experiment Telescope] experiment, one of the four instruments on board the Gamma Ray Observatory (GRO). GRO was successfully launched in April, 1991.”


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