George Braxton Pegram (October 24, 1876 – August 12, 1958) was an American physicist who played a key role in the technical administration of the Manhattan Project. He graduated from Trinity College (now Duke University) in 1895, and taught high school before becoming a teaching assistant in physics at Columbia University in 1900. He was to spend the rest of his working life at Columbia, taking his doctorate there in 1903 and becoming a full professor in 1918. His administrative career began as early as 1913 when he became the department's executive officer. By 1918, he was Dean of the Faculty of Applied Sciences but he resigned in 1930 to relaunch his research activities, performing many meticulous measurements on the properties of neutrons with John R. Dunning. He was also chairman of Columbia's physics department from 1913 to 1945.

Returning to administration as Dean in 1936, Pegram met Enrico Fermi on his arrival in the United States. In 1940 he brokered a meeting between Fermi and the US Navy at which the prospect of an atomic bomb was raised with the military for the first time. Following Marcus Oliphant's mission to the United States in August 1941 to alert the Americans to its feasibility, Pegram and his colleague Harold C. Urey led a diplomatic mission to the United Kingdom to establish co-operation on development of the atomic bomb. They soon found themselves on Vannevar Bush's S-1 Section coordinating technical research. Columbia's physics department was home to the SAM Laboratories, where many of the key technologies required for the bomb were developed.

After the war Pegram helped found the Brookhaven National Laboratory. He served as vice president of the university 1949 to 1950.

Early life

George Braxton Pegram was born in Trinity, North Carolina, one of the five children of William Howell Pegram, a professor of chemistry at Trinity College (now Duke University), and Emma, daughter of Braxton Craven, the college's founder and first president. He had two brothers and two sisters, all of whom graduated from Trinity College. His upbringing in the academic atmosphere of the campus left him with an appetite for careful methodical work and an inherent diplomacy.

Pegram graduated from Trinity College with a Bachelor of Arts (AB) degree in 1895, served briefly as the college librarian, and then became a high school teacher. He entered Columbia University in 1900, becoming an assistant in physics. He published his first two papers, on radioactive materials, the following year, and wrote his 1903 Doctor of Philosophy (PhD) thesis on "Secondary radioactivity in the electrolysis of thorium solutions". It was published in the Physical Review that year. During the summer break in 1905, he worked for the United States Coast and Geodetic Survey on measuring the Earth's magnetic field at its observation stations.

In those days, promising American scholars in physics would normally further their education overseas. Pegram was awarded a John Tyndall Fellowship for this purpose in 1907, and went to Germany, where he attended lectures at the Humboldt University of Berlin given by Max Planck and Walther Nernst. In 1908, he moved on to the University of Cambridge in England, where he heard lectures given by Sir Joseph Larmor. In his travels he visited some twenty European universities, and he met Florence Bement, a Wellesley College graduate from Boston. They renewed their acquaintance after they returned to the United States, and were married at her aunt's home in West Newton, Massachusetts on June 3, 1909. They had two sons, William, born in 1910, and John, born in 1916.

Early career

On returning to the United States in 1909, Pegram was appointed an assistant professor at Columbia. He became an associate professor in 1912, and a full professor in 1918. He became the head of the physics department on the death of William Hallock in 1913, and held this position until 1945. He also became acting Dean of Columbia's School of Mines, Engineering, and Chemistry in 1917, and was its dean from 1918 until 1930. During World War I he served on the administrative board of the Student Army Training Corps at Columbia. Classes commenced on October 1, 1918, with some 2,500 students. He was also dean of the US Army Radio School, US Army School of Photography, and US Army School of Explosives there, and was Director of Research of the United States Army Signal Corps.

In 1917 and 1918, Pegram served on a committee established by the National Research Council headed by the president of Columbia University, Nicholas Murray Butler, with Michael I. Pupin as its secretary, that created a quartz piezo-electric sound detector for locating submerged submarines. The device worked, and the Naval Experimental Station at New London, Connecticut, took over its development in September 1918. He was awarded an honorary Doctor of Science degree by Duke University in 1918. James Chadwick's discovery of the neutron in 1932 sparked a flurry of research into neutrons by Pegram and Dunning. Between 1933 and 1936, they would work together on two dozen papers, all on neutrons. He also collaborated with Harold Urey on separating oxygen isotopes. This period came to an abrupt end when Howard Lee McBain died suddenly on May 7, 1936, and Pegram became dean again on January 1, 1937.

Pegram died in Swarthmore, Pennsylvania on August 12, 1958. His papers are in the Columbia University Library.

Notes

References

  • APS Office of the Treasurer records of George B. Pegram, 1926-1957, Niels Bohr Library & Archives