Seriously? you do know that the first atom bomb was dropped on Japan during WWII in 1945 and not after.
Nazi Germany only got as far as a dirty bomb in Thüringia. They never achieved chain reaction.
The Germany idea of an Atom bomb was blowing up Plutonium with chemical explosives.
What did German scientists know?
Over the years, several authors have concluded that Heisenberg and his colleagues did not understand how an atomic bomb would work. These authors include the physicist Samuel Goudsmit, who in 1947 published the results of a US Army investigation – entitled
Alsos – into Germany’s bomb effort. The historian Paul Lawrence Rose came to the same conclusion in his 1998 book
Heisenberg and the Nazi Atomic Bomb Project 1939-1945. These critics argue that the German scientists did not understand the physics of a nuclear-fission chain reaction, in which fast neutrons emitted by a uranium-235 or plutonium nucleus trigger further fission reactions. Both Goudsmit and Rose also say the Germans failed to realize that plutonium can be a nuclear explosive.
Did Germany test an atomic bomb?
physicsworld.com