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Operation Trinity and Manhattan Project

Contributor: C. Peter Chen

ww2dbaseManhattan Project

ww2dbaseAs early as 1930, even prominent physicists such as Ernest Rutherford and Albert Einstein knew there were tremendous amounts of energy inside of atoms, but saw no way to release it. Things changed quickly, however, during the 1930s. In 1932, Sir John Cockcroft and Ernest Walton were able to cause a nuclear reaction for the first time by using artificially accelerated particles, and then in 1934, Irène and Frédéric Joliot-Curie and Enrico Fermi separately induced artificial radioactivity by bombarding atoms with alpha particles and neutrons, respectively. Finally, in Dec 1938, based on the work of Otto Hahn and Fritz Strassmann, Lise Meitner and Otto Robert Frisch published their theory of the potential of splitting uranium atoms. Coupled with the possibility of a chain reaction for a tremendous amount of energy release, people began to realize that artificially induced nuclear fission could be used as a powerful weapon.

ww2dbaseIn Sep 1939, a letter bearing the signature of physicist Albert Einstein was delivered to President Franklin Roosevelt, urging him to allocate sufficient funding for atomic weapons research. The letter was drafted by Leó Szilárd and Edward Teller who then presented it to Einstein with Szilárd’s plea that the more popularly known Einstein sign it. Agreeing Szilárd and Teller's thoughts, Roosevelt authorized the creation of the Uranium Committee under National Bureau of Standards chief Lyman Briggs, which began research programs at the Naval Research Laboratory in Washington, DC, United States in 1939. In 1940, the Uranium Committee was absorbed into the larger National Defense Research Committee. Nevertheless, progress was slow, partly due to the low sense of urgency as the United States had not yet entered the war.

ww2dbaseMeanwhile, scientists in Britain also embarked on a similar mission. In Mar 1940, at the University of Birmingham, research done by Otto Frisch and Rudolf Peierls eventually led to the Scientific Survey of Air Warfare's finding that an uranium bomb could be produced using merely 25 pounds of uranium-235, which was a feasible size for a weapon. This was something that the leading German physicist Werner Heisenberg, the lead scientist for Nazi Germany's atomic weapon research program, never achieved. The friendliness between Britain and the United States allowed this new finding to be shared between the two nations, but Briggs made no effort to share this new report with his physicists. Briggs' failure ultimately led to the atomic weapon research program to be transferred directly under National Defense Research Committee's chief, Vannevar Bush, in Nov 1941. Briefly, the administrative headquarters of the research project was located at 90 Church Street in the Borough of Manhattan in New York City, New York, United States. Although it was soon moved, the name Manhattan remained with the project.

ww2dbaseWith the United States entering the war in Dec 1941, research efforts accelerated. In early 1942, University of Chicago Metallurgical Laboratory joined in to study plutonium (which had just been discovered by Glenn Seaborg and his team in Feb 1941) and fission piles, while theoretical physicist J. Robert Oppenheimer of the University of California at Berkeley took over the research for critical mass calculations associated with weapon detonation. John Manley, a physicist at the University of Chicago Metallurgical Laboratory, was assigned to help Oppenheimer coordinate research efforts of over thirty different research and production sites scattered across the United States. Despite the numerous locations, however, the main weapons research and production were largely carried out at three top secret locations. The knowledge of these locations was not made known until the end of the war.

The facilities at the remote Los Alamos, New Mexico housed the main group of researchers and was responsible for final assembly of the bombs. This location was code named "Site Y."

The facilities at Oak Ridge, Tennessee, which had ready access to hydroelectric power, enriched uranium-235 and conducted plutonium production research. This location was code named "Site X."

The facilities at Hanford, Washington, which was near the Columbia River which supplied sufficient water to cool reactors, produced plutonium. This location was code named "Site W."

ww2dbaseAll three locations were strategically located far enough in-land to minimize aerial attack by Germany or Japan.

ww2dbaseIn an effort to better coordinate the weapons research, Roosevelt placed the US Army Corps of Engineers to oversee the operation. The first officer to head the effort was Colonel James Marshall, who failed to efficiently secure needed material for research and production. Replacing Marshall was Colonel Leslie Groves, who was the deputy in overseeing the successful completion of the large construction of the Pentagon building. Groves appointed Oppenheimer as the scientific director of the project, which surprised many due to Oppenheimer's radical political views. At the time, Groves renamed the project the Manhattan District, which secured the research project's legacy as the Manhattan Project. He was also promoted to the rank of brigadier general so that he would have adequate authority to deal with various issues with the project.

ww2dbaseWhile the research continued, the US Army actively searched out for additional uranium. Groves gave the responsibility of searching out for more uranium to Colonel Kenneth Nichols, who promptly visited the New York City office of Edgar Sengier. Sengier was the director of Union Minière du Haut Katanga, a company that owned the world's largest uranium mine in the Belgian colony of Congo. As it turned out, Sengier had been hoarding uranium since the start of the European political tension between Germany and the west, knowing that the material was critical in the development of atomic weapons. He hid one secret stockpile of eight tons of uranium oxide in French Morocco (which later became the basis for France's post-war nuclear program) and another stockpile of 1,250 tons of uranium ore at Staten Island, New York, United States. The stockpile hidden at Staten Island was eventually purchased by Nichols for Manhattan Project. Sengier later became the only non-US citizen to win the Medal of Merit award from the United States; he also received honors from Belgium, the United Kingdom, and France.

ww2dbaseOne of the first major hurdles was overcome on 2 Dec 1942, where the team led by Enrico Fermi at the University of Chicago successfully initiated the first self-sustaining nuclear chain reaction in a reactor code named Chicago Pile-1, and the project began to reach milestones at a healthy rate. British efforts up to this point, however, were slower than expected due to the lack of funding and further slowed by the unwillingness of the United States to collaborate. In Aug 1943, finally, it was agreed during the Quebec conference that a team of British and Canadian researchers were to join the Manhattan Project so that the best of Anglo-American efforts could be coordinated efficiently. By Jan 1944, uranium and plutonium production had reached a stage where the scientists could build working models of their theories. Very quickly, a gun-type fission weapon was drawn out where a mass of uranium-235 was shot down a gun barrel into another mass of uranium-235, creating the critical mass necessary to trigger an explosion; this method was so certain to work that no test was necessary, though there was not enough uranium-235 to conduct such a test anyway. The resulting uranium bomb was code named "Little Boy." The plutonium bomb was made with the synthetic element plutonium-239, made from uranium-238. Originally, the gun-type fission weapon was also to be the plan for the plutonium bomb, code named "Thin Man." However, in Apr 1944, physicist Emilio Segrè at Los Alamos discovered the gun-type trigger device was completely unsuitable for plutonium-239, and the gun-type trigger for the plutonium bomb was totally abandoned in Jul 1944, ending the "Thin Man" portion of the project. The alternative method to detonate the plutonium bomb, unlikely as it seemed at the time, was implosion, where a sub-critical mass of plutonium would be forced to collapse in on itself during a chemically-induced explosion, creating critical mass due to increased density. This method was only achieved after a reorganization that dedicated just about every scientist of the Manhattan Project to research this problem.

ww2dbaseBecause of the complexity of the implosion-style trigger, it was decided that a test must be conducted despite the wastage in plutonium, thus came Operation Trinity. The origin of the name was said to be coined by Oppenheimer, referring to the poetry of John Donne. Oppenheimer wrote to Groves in 1962

I did suggest [the name Trinity]... Why I chose the name is not clear, but I know what thoughts were in my mind. There is a poem of John Donne, written just before his death, which I know and love. From it a quotation: As West and East / In all flatt Maps-and I am one-are one,

So death doth touch the Resurrection. That still does not make a Trinity, but in another, better known devotional poem Donne opens, Batter my heart, three person'd God.

ww2dbaseOperation Trinity

ww2dbaseThe test for the implosion-style plutonium weapon was scheduled for 16 Jul 1945 at a location 35 miles southeast of Socorro, New Mexico, in the northern sector of the Alamogordo Bombing Range (now the White Sands Missile Range). The site was chosen to be remote enough to keep the test secret, plus the strength of the explosive was unknown so that the site's distance from civilization added a buffer zone. Planning for the test was assigned to Kenneth Bainbridge, a professor of physics at Harvard University, working under explosives expert George Kistiakowsky. An array of scientific equipment was gathered to retrieve data, while dozens of cameras operated by Berlyn Brixner's team were deployed to capture the visuals. From a military perspective, soldiers arrived as early as fall 1944 to safeguard the physical security, and by early 1945 checkpoints were established throughout the grounds, manned by military policemen.

ww2dbaseOn 7 May, more than two months before the test, a test explosion of 108 tons of TNT was conducted to calibrate the instruments. The scientists' predictions for the test spanned across the entire spectrum. Some of them predicted that the test would fail to produce any energy at all, while others thought the test would trigger the detonation of the entire atmosphere, thus laying the surface of the Earth to waste. Physicist I. I. Rabi, who predicted that the explosion would yield the same energy as 18 kilotons of TNT, would come closest to the actual result.

ww2dbaseOn the day of the atomic test, Oppenheimer and General Thomas Farrell, US Army officer placed in charge of the test, observed from one of the two bunkers 16 kilometers from the test site along with over 258 other personnel. Groves was among them as well, watching from the second bunker 32 kilometers away. From the top of a 20-meter steel tower, the plutonium weapon "Gadget" which had been assembled three days earlier at nearby McDonald Ranch House was detonated at 05:29:45 local time/11:29:45 UTC (delayed from the original time of 4:00am local time/10:00:00 UTC due to rain and lightning). The final countdown was read by physicist Samuel K. Allison. The explosion released energy equivalent to the explosion of about 20 kilotons of TNT, leaving a crater of mildly radioactive light green glass nicknamed Trinitite in the desert 3 meters deep and 330 meters wide. The shock of the explosion was felt over 300 kilometers away, and the mushroom cloud was 12 kilometers high. "It worked", mumbled Oppenheimer. "Now we are all sons of bitches", said Bainbridge. Oppenheimer later noted that a line from the Hindu scripture the Bhagavad Gita came to his mind as he watched the explosion: "I am become Death, the destroyer of worlds." In the official US Army report on the test, Farrell said that

The lighting effects beggared description. The whole country was lighted by a searing light with the intensity many times that of the midday sun. It was golden, purple, violet, gray, and blue. It lighted every peak, crevasse and ridge of the nearby mountain range with a clarity and beauty that cannot be described but must be seen to be imagined.

ww2dbaseTo cover up, the Alamogordo Air Base issued a press release noting that an ammunition dump exploded in an accident which caused no injuries, and the crater was filled as soon as observations were made by the scientists. The event remained in secret until after the destruction of Hiroshima on 6 Aug 1945. Three days after Hiroshima, Nagasaki was destroyed by the atomic bomb "Fat Man" which had the same design as the "Gadget" bomb used for Operation Trinity. On 12 Aug, the Smyth Report was released to the public with some technical information about the test.

ww2dbaseThe successful Operation Trinity test was considered by many as the start of the Atomic Age, as it was the test of a nuclear weapon technology. In 1952, the site of the explosion was bulldozed, and the remaining Trinitite was disposed of. Residual radiation remained as high as ten times higher than naturally occurring radiation even after 60 years.

ww2dbaseSoviet Efforts

ww2dbaseSoviet efforts to develop an atomic weapon began in Sep 1941, headed by Igor Kurchatov. The Soviet program was significantly smaller than its American counterpart, but it progressed relatively quickly due to an effective spy network that involved Los Alamos researchers Klaus Fuchs and Theodore Hall (who did not know that the other was also a spy).

ww2dbaseGerman Efforts

ww2dbasePhysicist Werner Heisenberg was the chief of Germany's efforts to develop an atomic bomb, who failed to build a reactor partly due to his decision to use heavy water as a neutron moderator. His research was further hampered by Allied efforts that denied the German research program of heavy water. After the war, Heisenberg insisted that he had never intended to use his research as a weapon in any case even though his in-progress heavy water reactor was built with government funding.

ww2dbaseJapanese Efforts

ww2dbaseJapanese researchers focused on uranium much like the American effort. Lieutenant General Takeo Yasuda of the Aviation Technology Research Institute of the Japanese Army was placed in charge of the research. He secured deposits of uranium ore in northern Korea, and invited Yoshio Nishida, Japan's leading nuclear physicist, to lead the scientists. In Hungnam, Korea, Japan constructed a nuclear installation and rumored to have successfully conducted a nuclear explosion at the site on 10 Aug 1945, four days after the Americans destroyed Hiroshima and Nagasaki. The Japanese installation at Hungnam was later dismantled and brought back to Russia by Soviet troops, with all of the remaining nuclear material, without any prior discussion with their Anglo-American allies.

ww2dbaseSources:

Robert Bullington, et. al. Armchair Reader World War II

Wikipedia.

Last Major Update: Jul 2009

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