The Physicists and the Bomb
 Quiz 2: November 13, 2000-solutions
  1. WWII nuclear explosions
    During the Second World War there were three (3) nuclear explosions. Characterize them as to location, effect(s), fissile isotope, method of detonation.
    1. First explosion
      Trinity site, near Alamagordo NM, tower; 239Pu; implosion; produced craters, melted sand ``Trinitite.''
    2. Second explosion
      Hiroshima, Japan, air drop from B-29; 235U; gun method, approximately 100,000 deaths
    3. Third explosion
      Nagasaki, Japan; air drop from B-29; 239Pu; implosion; approximately 50,000 deaths.
  2. The USSR
    1. Characterize the effort in the USSR before and after Hiroshima.
      Before Hiroshima, there was only a small-scale effort; after, it was given highest priority.
    2. What type of bomb was exploded at the first Soviet test? When was that test?
      It was a plutonium implosion bomb, virtually identical to the Trinity/Nagasaki model. The test was in late August, 1949.
    3. How important was espionage to the Soviet effort?
      It was essential to the first bomb, although the Soviet scientists proved perfectly capable of producing their own designs.
  3. The German WWII effort
    Discuss succinctly each of the following aspects of the German effort:
    1. Reactor development (including moderator issues)
      The Germans never succeeded in producing a self-sustaining chain reaction. They were hampered by an erroneous belief that graphite could not be used as a moderator in a natural uranium reactor. Their consequent reliance on ``Heavy Water'' (D2O) was affected by sabotage at the Norwegian source.
    2. Leadership and organizational issues
      The German effort was never centralized under a single command. There were competing programs under different agencies. The leading theorist, Werner Heisenberg, seems not to have done an analysis of a fast neutron bomb before learning of Hiroshima. The scientists never requested, or received, large-scale funding from the government.


File translated from TEX by TTH, version 2.77.
On 13 Nov 2000, 11:45.