Lawrence Marvin Langer (22 December 1913 – 17 January 2000) was a nuclear physicist and a group leader of the Manhattan Project which developed the atomic bombs that were dropped on Hiroshima and Nagasaki.

He also developed sonar and radar detectors during World War II and worked on the "gun" mechanism used to detonate the Uranium-235 bomb used on Hiroshima.

The year that he received his PhD, the President of Indiana University, Herman B Wells, had a vision to start a modern-day research program in the physics department.

[3] As the war approached, Langer was recruited to work in the MIT Radiation Laboratory where he was involved in flight-testing of radar prototypes in fighter planes.

Since he was not a naval officer, Langer had to train Navy Captain William S. "Deak" Parsons to arm the bomb once it was airborne using a wrench.

Langer was awaken from his night's rest on Little Boy by the sounds of the photographer's flash bulbs popping while they were documenting the Enola Gay before its historic flight.

He began to develop one of the world's major laboratories for nuclear spectroscopy and beta-ray spectral shapes becoming a leader in source and detector techniques.

[6] He and his colleague in theoretical physics, Emil Konopinski, produced a 1953 article in Annual Review of Nuclear Science on beta decay that was widely cited.