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Manhattan Project Glossary

Web Master's Note:  Below is a glossary of the Manhattan Project.  If you "click" on the numbered list below, you will be taken to a brief description for that item.  Also, in many instances, there will be an additional link should you want more information on the topic or quite possibly a photograph.

This page in under construction and new material will be added on a continuing basis.

 

  1. 509th Composite Group
  2. Alsos Missions
  3. Bockscar
  4. Box 1663
  5. British Mission
  6. Clinton Engineer Works
  7. Corp of Engineers
  8. Enola Gay
  9. Fat Man
  10. Fission
  11. Gadget
  12. Hanford Engineer Works
  13. The "Hill"
  14. Implosion-Type Atomic Bomb
  15. Jumbo
  16. K-25 Plant - Oak Ridge
  17. Little Boy
  18. Manhattan Project
  19. Maud Committee
  20. Met Lab
  21. Oralloy
  22. Pile
  23. Plutonium
  24. Project Alberta
  25. Project Silverplate
  26. Pumpkins
  27. Queen Mary
  28. Rad Lab
  29. S-50 Plant - Oak Ridge
  30. Site Y
  31. Tickling the Tail...
  32. Tinian Island
  33. Trinity Test Site
  34. Y-12 Plant - Oak Ridge
  35. X-10 Plant - Oak Ridge

509th Composite Group ...

The 509th Composite Group, part of the 20th Air Force of the U. S. Army Air Force, was organized as the weapon delivery arm of the Manhattan Project.  After its formation at Fairmont, NB it relocated to Wendover Army Air Field in Wendover, UT where extensive training took place utilizing the newly-modified B29 Superfortresses.  In early 1945, the entire group moved to Tinian Island in the South Pacific for further training and to ready itself for the upcoming missions to Japan.

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ALSOS Missions ...

The purpose of the Manhattan Project was to produce an atomic weapon before Germany could.  Very little espionage activities were carried out by the Allies to determine Germany's nuclear capabilities because to do so would reveal our hand.  Therefore, it wasn't until the Allies began making inroads into Europe that General Leslie Groves initiated the ALSOS missions.  In a nutshell, the ALSOS missions were comprised of a team of military security personnel and scientists; their mission to capture enemy scientists and raw materials such as uranium...and, in the process to determine how far Germany had progressed toward developing an atomic bomb.  There were three ALSOS missions:  ALSOS I into Italy, ALSOS II into France, and ALSOS III into Germany itself.

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Bockscar ...

"Bockscar" was the name given to the B29 Superfortress that dropped the second atomic bomb on the Japanese city of Nagasaki on August 9, 1945. (often misspelled as "Boxcar" or "Bock's Car")

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Box 1663 ...

"Box 1663", Santa Fe, NM was the enigmatic address used by all residents of Los Alamos.  It was required for all incoming and outgoing mail.  In addition, all outgoing mail was read and censored by Manhattan Project security personnel.

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The British Mission ...

The British Mission to Los Alamos was a group of top-notch British physicists who had played a crucial role in encouraging America's bomb effort and had been invited to Los Alamos to work on the project.  Some members also rode along as "observers" on the two atomic bomb missions over Japan.

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Clinton Engineer Works ...

One of the three major facilities of the Manhattan Engineer District (MED), the Clinton Engineer Works was the name given to the huge uranium enrichment facilities and the pilot plant for plutonium production.  Located a short distance from Knoxville, TN, it was renamed Oak Ridge AFTER the war.

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Corp of Engineers ...

The "Corp of Engineers" is the construction arm of the U. S. Army.  During World War II, the Corp was responsible for all construction of military installations.  Domestically, the Corp of Engineers is organized into many "districts" that encompass the continental U.S.  General Groves, who had been in charge of building the Pentagon in Washington, DC, was eventually put in charge of the Manhattan Project.  Since he was affiliated with the Corp of Engineer's office in New York City and since he was looking for a name that was not at all suggestive of its true purpose, he chose the name "Manhattan Project" and organized it under the auspices of the "Manhattan Engineer District" (MED) in New York City.

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Enola Gay ...

The "Enola Gay" was the name given to the B29 Superfortress that dropped the first atomic bomb on the Japanese city of Hiroshima on August 6, 1945. (the name was derived from Col. Paul Tibbet's mother name)

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Fat Man ...

"Fat Man" was the name given to the plutonium implosion-type atomic bomb and was the second bomb to be dropped on the Japanese city of Nagasaki.  It replaced the inefficient gun-type bomb "Little Boy".

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Fission ...

Fission is the term given to the process of "splitting" atoms through their bombardment by neutrons.  The term was actually first coined by the physicist Otto Frisch (nephew of Lise Meitner). 

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Gadget ...

"Gadget" was the name given to the first atomic bomb which was detonated at the Trinity Test Site outside Alamagordo, New Mexico on July 16, 1945.  This plutonium implosion-type bomb was similar to the "Fat Man" bomb dropped on the Japanese city of Nagasaki.

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Hanford Engineer Works ...

One of the three major facilities of the Manhattan Engineer District (MED), the Hanford Engineer Works was home to the giant reactor "piles" and the cavernous plutonium separation and concentration facilities.  Built and operated by DuPont, it was one of the largest construction projects ever undertaken, employing at one time nearly 45,000 construction workers.

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The "Hill" ...

Residents of Los Alamos referred to the military installation as "the hill", due to its 7,200 foot elevation.

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Implosion-Type Atomic Bomb ...

The "Implosion-type" atomic bomb was one that utilized (greatly simplified definition) an array of exterior explosive charges placed on a sphere that were focused inward toward the core, and when detonated correctly compressed a core of plutonium inward, compressing it from the size of a grapefruit to that of a tennis ball, thereby creating a critical mass and inducing a nuclear explosion.  This procedure was so complicated that it took the best minds of the Los Alamos explosives group many months to perfect it,  The process was first suggested by physicist Seth Neddermeyer.  Both the "Gadget" tested at Trinity and the "Fat Man" bomb dropped on the Japanese city of Nagasaki were implosion-type weapons.

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Jumbo ...

"Jumbo" was the name given to the large steel vessel which was originally designed to contain the first atomic explosion.  It was never used!  Very interesting and little known story.

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K-25 Plant - Oak Ridge ...

The K-25 Plant was one of four primary production facilities at Oak Ridge.  Construction on this plant began on September 27, 1943 and Union Carbide was the contracted operator.  Its mission was to provide enriched uranium utilizing the gaseous diffusion process.

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Little Boy ...

"Little Boy" was the name given to the uranium gun-type atomic bomb and was the first to be dropped on the Japanese city of Hiroshima.  It was the first and last of this type of device and was replaced by the more efficient implosion-type plutonium bomb..."Fat Man".

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The Manhattan Project ...

The Manhattan Project was the code name for America's atomic bomb development efforts during World War II.  Its name originated from the fact that it was part of the U. S. Army Corp of Engineers and organized under the Manhattan Engineer District in New York City.  The MED (Manhattan Engineer District) encompassed all of the far-reaching labs and installations scattered throughout the country.

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The MAUD Committee ...

In July of 1941, Vannevar Bush and James Conant, new head of the National Defense Research Committee, received a copy of a draft report from their liaison office in London.  The report, prepared by a group codenamed the MAUD committee and set up by the British in the spring of 1940 to study the possibility of developing a nuclear weapon, maintained that a sufficiently purified critical mass of uranium-235 could fission even with fast neutrons.

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The Met Lab ...

The "Met Lab" was short for the Metallurgical Laboratory at the University of Chicago.  Much of the theoretical and experimental work on uranium and plutonium took place here.  Directed by Nobel laureate Arthur Holly Compton, it was home to many of the foremost physicists and chemists of the time.  It was here that Nobel laureate Enrico Fermi first achieved a sustained chain reaction on December 2, 1942. 

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Oralloy ...

Oralloy was the code name often used for the enriched uranium being produced at Oak Ridge.

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Pile ...

The term "Pile" refers to a nuclear reactor.  Coined by Enrico Fermi at the Met Lab, it was based on the first rudimentary nuclear reactor which was nothing more than a pile of uranium and graphite blocks.  Later on the term was carried forward to Hanford where the giant reactors became known as Pile B, Pile D, etc.

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Plutonium ...

Plutonium is a heavy metal that does not exist naturally.  It is produced as a by-product of the fission process in a nuclear reactor.

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Project Alberta ...

Project Alberta was the code name for a team of scientific personnel (civilian and military) which were sent from Los Alamos to Tinian Island to assemble and arm the "Little Boy" and "Fat Man" atomic bombs. 

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Project Silverplate ...

Project Silverplate was the code name for the top secret mission to develop specially-modified B29 superfortresses for use by the 509th Composite Group.  It carried a Triple A ("AAA") priority.

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Pumpkins ...

Pumpkins was a coined term for the dummy "Fat Man" bombs dropped on practice missions by the 509th Composite Group.  They were mustard colored and were of the approximate size and weight of the "Fat Man" bomb.

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Queen Mary ...

The "Queen Mary's" were the common name given to the cavernous plutonium separation facilities at the Hanford Engineer Works.

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Rad Lab ...

The "Rad Lab" was the short name for the Radiological Laboratory at Berkeley (University of California).  It's director was Nobel laureate Ernest O. Lawrence.  He gained recognition for his 60" cyclotron and was the driving force behind the electro-magnetic separation of uranium that formed the basis for the Y-12 complex at Oak Ridge.  In addition, Berkeley was the center for theoretical physics in the United States and spawned such notables as J. Robert Oppenheimer, Glenn Seaborg, and Emilio Segre.

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S-50 Plant - Oak Ridge ...

The S-50 Plant was one of four primary production facilities at Oak Ridge.  Construction on this plant began on September 27, 1944 and Union Carbide was the contracted operator.  Its mission was to provide enriched uranium utilizing the liquid thermal diffusion process which had been pioneered at the Naval Research Lab at the Philadelphia Navy Yard.

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Site "Y" ...

Site Y was the code name for the Los Alamos Laboratory.

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Tickling the Tail of the Dragon ...

"Tickling the Tail of the Dragon" was a coined term for the criticality experiments to determine the amount of fissionable material needed for a sustained chain reaction.  There was always an element of danger involved.  Two Los Alamos physicists lost their lives whule conducting the experiemnt:  Harry Daghlian and Louis Slotin, Jr.

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Tinian Island ...

Tinian Island is an island in the Marianas Chain in the South Pacific.  It was one of a series of island captured by the Americans on their island hopping mission to Japan.  In 1945, it served as the headquarters of the 509th Composite Group.  The final assembly of both the Little Boy and Fat Man atomic bombs were performed at Tinian.  Tinian Island had several long, parallel runways capable of launching heavily laden B29 bombers.  Both atomic missions to Japan originated from Tinian.

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Trinity Test Site ...

The Trinity Test Site was where the first successful detonation of an atomic bomb took place.  On the early morning of July 16, 1945, the implosion-type weapon known as "The Gadget" exploded with the force of several thousand tons of TNT and lit up the Jornada de Muerta valley.  Situated about 150 miles from Los Alamos, it is located near Alamagordo, NM and is now known as the White Sands Missle Range.

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X-10 Plant - Oak Ridge ...

The X-10 Graphite Reactor Plant was one of four primary production facilities at Oak Ridge.  Construction on this plant began in February of 1943 and DuPont was the contracted operator.  Its mission was to act as a semi-works (pilot-plant) to work out kink in the production of plutonium from a "pile".  Based upon experimental data from the Met Lab in Chicago, it formed the basis for the up-scaled plutonium production and concentration facilities at Hanford, Washington.

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Y-12 Plant - Oak Ridge ...

The Y-12 Plant was one of four primary production facilities at Oak Ridge.  Construction on this plant began on February 18, 1943 and Tennessee Eastman (sub. of Kodak) was the contracted operator.  Its mission was to provide enriched uranium utilizing the electromagnetic separation process, which had been pioneered by Ernest O. Lawrence at Berkeley.

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 Official Test Count Commenced 11/30/01 - 

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