Who had find the atomic bomb?

Answer 1

Are you asking "Who found the first atomic bomb just lying there and ready to use?". If you are, the answer is nobody, you don't find atomic bombs. Atomic bombs were invented, designed, then built.

1. Leo Szilard in London invented the atomic bomb in 1933. But nobody could build it as no material was known that would support a neutron chain reaction.
2. Otto Hahn in Berlin discovered that the rare isotope Uranium-235 would fission and release neutrons in 1938. Uranium-235 should support a neutron chain reaction, making Szilard's atomic bomb possible to build.
3. E. O. Lawrence in Berkley discovered Plutonium in 1940 using his 36 inch cyclotron. Plutonium too fissioned and released neutrons, making it a second candidate for building an atomic bomb.
4. The scientists & engineers of the Manhattan Project at Los Alamos designed a Uranium & a Plutonium based bomb between 1943 & 1945.
5. The US government built the complex nuclear industrial infrastructure needed to produce Uranium-235 & Plutonium metals in quantity and machine them to the desired shapes between 1943 & 1945.
6. The scientists & engineers at Los Alamos began building actual atomic bombs in June/July of 1945 when "oralloy" & "product" (codenames for Uranium-235 & Plutonium respectively) began to be available in the required quantities.
7. The first bomb was tested July 16, 1945.
8. The second bomb was the first used in combat August 6, 1945.
9. The third bomb was the second and last used in combatAugust 9, 1945.
10. The fourth bomb was built and was scheduled for use in combat late in August 1945. It was not needed and was returned to Los Alamos.
11. Three more atomic bombs were scheduled to be built and used in combat in September 1945.
12. Three more atomic bombs were scheduled to be built and used in combat in October 1945.
13. Seven more atomic bombs were scheduled to be built and used in combat in November 1945.
14. Seven more atomic bombs were scheduled to be built and used in combat in December 1945.