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U.S. Department of Energy
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A Tale of Two Bomb Designs: Why were both Little Boy and Fat Man created?

Technical Report ·
DOI:https://doi.org/10.2172/1875784· OSTI ID:1875784
 [1]
  1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Little Boy and Fat Man. Two types of nuclear weapons were developed at the Los Alamos wartime lab in an effort to help end World War II. Both would be released above Japan just days apart in August 1945, and just weeks after the Trinity test in the New Mexico desert. These weapons were, however, as different as their monikers imply. Little Boy was a uranium, gun-type weapon, whereas Fat Man was a plutonium, implosion-style weapon. Two types were needed because there was only enough uranium for one gun-type weapon and the U.S. government knew it would need to make more than one weapon. Also, the unattainable challenges of a plutonium gun-type design prompted the shift to the implosion-style weapon.
Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
DOE Contract Number:
89233218CNA000001
OSTI ID:
1875784
Report Number(s):
LA-UR-22-26712
Country of Publication:
United States
Language:
English

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