Person

Manhattan Project Scientists: Louis Alexander Slotin

Black and white photo of a man with short dark hair and glasses.
Louis Slotin fell victim to a lethal dose of radiation at Los Alamos.

LOS ALAMOS NATIONAL LABORATORY

Quick Facts
Significance:
Physicist at Los Alamos who died of radiation poisoning
Place of Birth:
Winnipeg, Manitoba, Canada
Date of Birth:
December 1, 1910
Place of Death:
Los Alamos, NM
Date of Death:
May 30, 1946
Place of Burial:
Winnipeg, Manitoba, Canada
Cemetery Name:
Shaarey Zedek Cemetery

Born in Winnipeg, Manitoba, Canada in 1910, Louis Slotin enrolled at the University of Manitoba at just 16 years of age. After receiving his Bachelor of Science and Master of Science in the early 1930s, Slotin earned his PhD in biochemistry at London University in 1936.  

In 1942, Slotin began working for the Manhattan Project at the University of Chicago’s Met Lab under Enrico Fermi and was present when the world’s first nuclear reactor, CP-1, reached criticality on December 2 that same year. Slotin worked at Oak Ridge in 1943, also witnessing the X-10 Graphite Reactor reach criticality on November 4. In 1944, Slotin relocated to Los Alamos to work in the Weapon Physics Division. At Los Alamos, Slotin showcased his skills as a bomb assembler and was assigned to build the core of the Gadget, the world’s first nuclear test device. In addition, Slotin performed several criticality tests, designed to determine the critical mass values of fissile materials. Because of the danger of nuclear fission, criticality tests came to be known as “tickling the dragon’s tail.” 

After the war, on May 26, 1946, Slotin was conducting a criticality test consisting of two berrylium-coated half spheres around a plutonium core. The test was designed to bring the two halves slowly together without touching, bringing the plutonium core closer to criticality. The screwdriver that Slotin was using to keep the halves separated slipped, filling the room with a bright blue light as the halves collided. Slotin immediately used his body to shield his colleagues in the room, exposing himself to a massive dose of radiation. Slotin was rushed to the hospital where he died of acute radiation poisoning nine days later, becoming the second person to die of accidental radiation poisoning at Los Alamos. 

Manhattan Project National Historical Park

Last updated: January 11, 2023