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National Museum of Nuclear Science & History

Herbert M. Lehr was a member of the Special Engineer Detachment who worked at Los Alamos during the Manhattan Project. Lehr was present at the Trinity test, where he helped transport and assemble the test bomb’s plutonium core.

Lehr joined the army initially to serve with the Signal Corps, where he was instructed in the use of radar and radio technologies. Lehr then entered the Army Specialized Training Program, during which he studied electrical engineering at the University of Minnesota. He was then transferred to the Manhattan District and sent to Los Alamos. After a few months at Los Alamos, Lehr was granted his bachelor’s degree in electrical engineering from the City College of New York based on his studies in the Army.

As a member of the Special Engineer Detachment at Los Alamos, Lehr worked in the physics division. He worked first with Don Kerst, the inventor of the betatron, on the construction of radiation counting equipment. Later, Lehr worked with Marshall Holloway on core design for the uranium bomb. Lehr helped set up the McDonald Ranch House for the Trinity test, then returned to help transport and assemble the Gadget’s plutonium core at the site.

Lehr was discharged after the war on February 6, 1946, but returned to Los Alamos to help Holloway prepare for the Operation Crossroads tests at Bikini Atoll as a technical aide. Lehr helped run the various experiments that were performed in coordination with the two detonations.

After the nuclear tests, Lehr worked as an administrative officer for the Physics Department at Brookhaven National Laboratory under Samuel Goudsmit, and later worked for Boeing as an engineering supervisor for thirty years before retiring in 1987.

Herbert Lehr’s Timeline
1922 Feb 15th Born in New York.

19431946 Served in the U.S. Army as part of the Special Engineer Detachment.

1946 Mar1946 Sep Served as a technical aide to Marshall Holloway during the Operation Crossroads nuclear tests at Bikini Atoll.

Herb Lehr with the Active Material

Louis Slotin and Herb Lehr at the assembly of the Trinity "Gadget." The uranium tamper is on the box in front of Lehr.

Herb Lehr and Harry Daghlian transporting the plutonium core before the Trinity Test

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