The Manhattan ProjectThe Making of an Atomic Bomb

The Setting (1930’s – 1940’s)

•World War II was happening and many important Jewish scientists were fleeing to the USA to work▫Einstein (Princeton), Rutherford (Harvard),

Szilard (Brown), and others•Einstein had published his famous E =

mc2

•Work had been done with fission (splitting an atom), but most of the work was done in Germany .

The Idea – July 1939

•The first to believe that atomic bomb could be made were Leo Szilard and two other Hungarians

•Attempted to contact FDR, but unsuccessful.

•Met with Einstein▫Einstein wrote a letter to FDR

The Chicago Test – December 1941•Had to determine if sustainable nuclear

reaction was possible.▫$6000 Grant

•Performed at the University of Chicago▫Italian named Enrico Fermi in charge.

•“Homemade” Nuclear Reactor▫500 Tons of Granite Bricks

•First self sustaining nuclear reaction ever!

The Manhattan Project – Sept. 1942

•General Groves put in charge.▫Career military man who knew very little

about science.•Groves selected scientists from around

the US▫J Robert Oppenheimer – Head Researcher

Young Scientist from Cal Questionable background Brilliant, but had never stuck with anything

long enough to win a Nobel Prize.

Site Y – November 1942

•Requirements▫Not near a border or large city▫Decent transportation and moderate

climate▫Adequate water and electrical supply.

•Los Alamos, NM chosen▫Construction began immediately▫Locals told it was going to be an “electric

rocket” facility.

The Recruitment – Winter 1942• Oppenheimer tried to attract the best scientists in

the world to Los Alamos. (40+)▫Bohr - Model of the atom (Nobel Prize, 1922)▫Feynman – Quantum Electronics (Nobel Prize, 1965)▫Von Neumann – Mathematician▫Szilard – Physicist ▫Fermi – Developed 1st Reactor (Nobel Prize, 1938)▫Chadwick – Discovered Neutron (Nobel Prize, 1935)▫Rutherford – Discovered Nucleus (Nobel Prize,

1924)▫Teller – Later developed the H Bomb (Nobel Prize,

1955)

The Plan

•Make three bombs▫One uranium bomb▫Two plutonium bombs – 1 practice/1 real

•Uranium Bomb▫Could be set off by colliding two masses of

uranium.•Plutonium Bomb

▫To unstable to be collided▫Had to develop a new strategy

The Other Sites

•Oak Ridge, TN▫Purified Uranium

•Richland, WA▫Made and Purified Plutonium

•Both sites had multiple problems in the construction and were far behind schedule in the early years of the project▫Worried that there wouldn’t be enough fuel

for the bombs.

The Germans •Heisenberg

▫Only major scientists who stayed in Germany to help Nazis.

•US had a spy follow him throughout the war•Attempted to contact Bohr

▫Bohr met him and was given “secret” information.

•After the war found out that Germany was years behind the US in the development of an atomic bomb.

http://en.wikipedia.org/wiki/File:Bundesarchiv_Bild183-R57262,_Werner_Heisenberg.jpg

The Trinity Site – July 1945

•Selected a site to test the plutonium bomb. Near Sante Fe.

•Test Bomb▫Plutonium bomb – Called Gadget

•Two observation bunkers▫20 miles and 5.7 miles away

•Performed prior to Truman’s meeting with Stalin and Churchill.▫Success gave new president Truman more

clout.

The Test Results

•Deemed a complete success▫Flash seen in 3 states – Very colorful▫Mushroom cloud was about 38,000 ft in the

air. ▫Everything within a 1 mile radius

annihilated. ▫Heat at the center of the explosion was

estimated to be the same temperature as the sun. Fused sand into green-grey glass.

•Locals told that it was a test of rockets and pyrotechnics.

The Spies• The Rosenbergs – Convicted in 1949

▫Convicted of sharing the ideas for the new plutonium bomb with Germans.

▫Sentenced to Death• Klaus Fuchs – Convicted 1954

▫Pass on very valuable information to East Germany

▫British Citizen – Tried in England. • Ted Hall

▫Never actually convicted▫Admitted it late in life

After Trinity

•The Manhattan project officially ended in July 1945

•Bombs were assembled by hand after the project’s official end

•Produced two bombs that were dropped on Japan. ▫Fat Man – Plutonium▫Little Boy - Uranium