[PAR] [TLE] Louis Slotin [SEP] Louis Alexander Slotin (1 December 1910 – 30 May 1946) was a Canadian physicist and chemist who worked on the Manhattan Project.  During World War II, Slotin conducted research at Los Alamos National Laboratory.  He performed experiments with uranium and plutonium cores to determine their critical mass values.  On 21 May 1946, Slotin was conducting a demonstration when he accidentally initiated a fission reaction, which released a burst of hard radiation.  He received a lethal dose of radiation and died of acute radiation syndrome nine days later.  Slotin was the second person to die from a criticality accident, following the death of Harry Daghlian, who had been exposed to radiation by the same core that killed Slotin.  Slotin was publicly hailed as a hero by the United States government for reacting quickly and preventing his accident from killing any colleagues.  He was later criticized for failing to follow protocol during the experiment. [PAR] [TLE] Manhattan Project [SEP] The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons.  It was led by the United States with the support of the United Kingdom and Canada.  From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers.  Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs.  The Army component of the project was designated the Manhattan District; "Manhattan" gradually superseded the official codename, Development of Substitute Materials, for the entire project.  Along the way, the project absorbed its earlier British counterpart, Tube Alloys.  The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US $2 billion (about $ in 2016 dollars).  Over 90% of the cost was for building factories and to produce fissile material, with less than 10% for development and production of the weapons.  Research and production took place at more than 30 sites across the United States, the United Kingdom, and Canada.
[PAR] [TLE] Louis Slotin [ SEP ] Louis Alexander Slotin ( 1 December 1910 – 30 May 1946 ) was a Canadian physicist and chemist who worked on the Manhattan Project . During World War II , Slotin conducted research at Los Alamos National Laboratory . He performed experiments with uranium and plutonium cores to determine their critical mass values . On 21 May 1946 , Slotin was conducting a demonstration when he accidentally initiated a fission reaction , which released a burst of hard radiation . He received a lethal dose of radiation and died of acute radiation syndrome nine days later . Slotin was the second person to die from a criticality accident , following the death of Harry Daghlian , who had been exposed to radiation by the same core that killed Slotin . Slotin was publicly hailed as a hero by the United States government for reacting quickly and preventing his accident from killing any colleagues . He was later criticized for failing to follow protocol during the experiment . [PAR] [TLE] Manhattan Project [ SEP ] The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons . It was led by the United States with the support of the United Kingdom and Canada . From 1942 to 1946 , the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers . Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs . The Army component of the project was designated the Manhattan District ; " Manhattan " gradually superseded the official codename , Development of Substitute Materials , for the entire project . Along the way , the project absorbed its earlier British counterpart , Tube Alloys . The Manhattan Project began modestly in 1939 , but grew to employ more than 130,000 people and cost nearly US $ 2 billion ( about $ in 2016 dollars ) . Over 90 % of the cost was for building factories and to produce fissile material , with less than 10 % for development and production of the weapons . Research and production took place at more than 30 sites across the United States , the United Kingdom , and Canada .
What two countries supported the project that Louis Slotin died working on?
What two countries supported the project that Louis Slotin died working on ?
the United Kingdom and Canada
the United Kingdom and Canada