Operation Trinity and Manhattan Project
Contributor: C. Peter Chen
As recently 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, Irčne 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.
On 2 Aug 1939, Hungarian Jewish refugee in the United States Leó Szilárd co-authored a letter with Albert Einstein, urging President Franklin Roosevelt to allocate sufficient funding for atomic research due to the potential application as a weapon. The letter reached Roosevelt's desk in Sep, who agreed with the scientists' urging, and 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.
Meanwhile, 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 of sharing 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.
With 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 which 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, enricheduranium-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".
All three locations were strategically located far enough in-land to minimize aerial attack by Germany or Japan.
In 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.
While 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 Miničre 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.
One of the first major hurdle overcame took place 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 on 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 Segrč 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.
Because 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
The 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.
On 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.
On 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
To 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.
The 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.
Soviet 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).
Physicist Werner Heisenberg was the chief of Germany's efforts to develop an atomic bomb, who failed to build a reactor partly due to him heading down the wrong direction by using 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 by government money.
Japanese 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.
Sources: Armchair Reader World War II, Wikipedia.
Operation Trinity and Manhattan Project Timeline
|16 Jan 1939||Austrian physicists Lise Meitner and Otto Frisch successfully achieved nuclear fission in an experiment in Sweden.|
|25 Jan 1939||Uranium atom was split for the first time at Columbia University in the United States.|
|26 Jan 1939||President Franklin Roosevelt approved atomic research efforts in the US.|
|2 Aug 1939||In a letter written by Leó Szilárd and signed by Albert Einstein, the two physicists urged US President Franklin Roosevelt to allocate funding for atomic weapons research.|
|11 Oct 1939||Leó Szilárd and Albert Einstein's letter (sent on 2 Aug 1939) reached Roosevelt, who agreed to establish a committee for the research of nuclear energy as a weapon. This led to Roosevelt's decision to establish the Uranium Advisory Committee shortly after.|
|21 Oct 1939||The Uranium Advisory Committee in the United States, headed by Lyman Briggs of the National Bureau of Standards, met for the first time. The committee had a budget of US$6,000 at this time.|
|10 Apr 1940||Henry Tizard established the Military Application of Uranium Detonation (MAUD) Committee in the United Kingdom to investigate the feasibility of an atomic weapon.|
|1 Jul 1940||The responsibility for nuclear fission research in the United States was transferred to the National Defense Research Committee under Vannevar Bush.|
|23 Feb 1941||Dr. Glenn T. Seaborg chemically identified the recently discovered new element Plutonium in the 60-inch cyclotron at the University of California at Berkeley, California, United States.|
|26 Feb 1941||American scientists Glenn Seaborg and Arthur Wahl discovered Plutonium.|
|17 May 1941||Arthur Compton and the United States National Academy of Sciences published a report noting the success rate of developing an atomic weapon was favorable. On the same day, Vannevar Bush created the Office of Scientific Research and Development (OSRD).|
|2 Jul 1941||The British Military Application of Uranium Detonation (MAUD) Committee assigned the responsibility of writing its final draft of the report of its findings on the development of atomic weapons to James Chadwick.|
|15 Jul 1941||The British Military Application of Uranium Detonation (MAUD) Committee issued its final report on atomic weapons.|
|17 Sep 1941||At a conference in Copenhagen, Denmark, German physicist Werner Heisenberg warned his mentor Niels Bohr that Germany had embarked on atomic weapon research and gave him a drawing of a reactor as proof.|
|3 Oct 1941||The official copy of the British Military Application of Uranium Detonation (MAUD) Committee Report, written by James Chadwick, reached Vannevar Bush.|
|9 Oct 1941||Vannevar Bush took the British Military Application of Uranium Detonation (MAUD) Committee Report to US President Franklin Roosevelt, who agreed to work together with the British to develop atomic weapons.|
|6 Dec 1941||Vannevar Bush and Arthur Compton assigned Harold Urey to develop research into gaseous diffusion as a uranium enrichment method and Ernest Lawrence to investigate electromagnetic separation methods.|
|18 Dec 1941||The S-1 Section of the United States Office of Scientific Research and Development, the forerunner of the Manhattan Project, held its first meeting.|
|13 Sep 1942||At a meeting of the S-1 Section Executive Committee of the United States Office of Scientific Research and Development (OSRD), a decision was reached to build a laboratory to study fast neutrons. This study was to be codenamed Project Y.|
|24 Sep 1942||Leslie Groves purchased 210 square kilometers (52,000 acres) of land in Tennessee, United States. Also known as Site X, it would soon become the Oak Ridge site of the Manhattan Project.|
|26 Sep 1942||The Manhattan Project was given permission to use the highest wartime priority rating by the United States War Production Board.|
|15 Oct 1942||Robert Oppenheimer was appointed, by Leslie Groves, to coordinate the scientific research of the Manhattan Project at Site Y, a location yet to be finalized.|
|6 Nov 1942||Groves and Oppenheimer visited Los Alamos, New Mexico, United States and agreed that it was suitable as the location for Site Y for the Manhattan Project.|
|2 Dec 1942||Enrico Fermi's atomic reactor Chicago Pile-1 at the University of Chicago, Illinois, United States initiated the world's first self-sustaining nuclear chain reaction.|
|18 Feb 1943||The construction for a large electromagnetic separation plant for enriching uranium, codenamed Y-12, began construction at Manhattan Project's Oak Ridge site in Tennessee, United States.|
|28 Feb 1943||Construction began on the first full-scale plutonium production reactor in the world at Hanford, Washington, United States.|
|19 Aug 1943||As discussed in the Quebec Conference between US President Franklin Roosevelt and British Prime Minister Winston Churchill, British scientists, including Klaus Fuchs, were to join the Manhattan Project.|
|4 Oct 1943||Construction began for the first nuclear reactor at the Hanford Site of the Manhattan Project in Washington, United States.|
|3 Mar 1944||An American B-29 bomber dropped a dummy atomic bomb at Muroc Army Air Force Base in California, United States at the altitude of 24,000 feet. The test bomb considerably damaged the aircraft's bomb bay doors as it exited the aircraft.|
|5 Apr 1944||At Los Alamos, New Mexico, United States, Emilio Segrč received the first sample of reactor-refined plutonium from Oak Ridge, Tennessee, United States. He would soon discover that the spontaneous fission rate of this plutonium was too high for use in a gun-type fission weapon.|
|4 Jul 1944||J. Robert Oppenheimer revealed Emilio Segrč's final measurements to the Manhattan Project scientists at Los Alamos, New Mexico, which concluded that the "Thin Man" design for a gun-type plutonium weapon was not feasible.|
|20 Jul 1944||The staff at the Los Alamos site of the Manhattan Project shifted focus to work on the implosion mechanism for the atomic bomb.|
|25 Jul 1944||The first preliminary test of the RaLa Experiment was performed by the scientists of the Manhattan Project; it was the first in a series of experiments attempting to create a spherical implosion to detonate a nuclear weapon.|
|2 Sep 1944||While attempting to unclog a uranium enrichment device at the Philadelphia Navy Yard, Pennsylvania, United States for the Manhattan Project, chemists Peter Bragg, Douglas Meigs, and Arnold Kramish accidentally set of an explosion, which sprayed liquid uranium hexafluoride and hydrofuoric acid on them. Bragg and Meigs were killed, while Kramish and two soldliers, George LeFevre and John Tompkins, were seriously injured.|
|22 Sep 1944||The first RaLa Experiment of the Manhattan Project with a radioactive source was performed.|
|9 Dec 1944||The US Army Air Forces established the 509th Composite Group for atomic weapon delivery.|
|14 Dec 1944||The RaLa Experiment of the Manhattan Project yielded evidence that spherical implosion was possible for compression of the plutonium pit of an atomic bomb.|
|17 Dec 1944||The newly established USAAF 509th Composite Group was activated. The group's mission was to deliver atomic weapons.|
|7 Jan 1945||The RaLa Experiment of the Manhattan Project conducted its first test using exploding bridgewire detonators.|
|14 Jan 1945||The RaLa Experiment of the Manhattan Project conducted its second test using exploding bridgewire detonators.|
|13 Apr 1945||More than 300 American B-29 bombers attacked various targets in and near Tokyo, Japan. The smaller of the two cyclotrons at the Riken Institute was destroyed.|
|11 Jun 1945||James Franck and other Metallurgical Laboratory scientists issued the Franck Report, arguing for a demonstration of an atomic bomb before using it against an enemy target.|
|16 Jul 1945||The Americans successfully detonated an atomic bomb at Alamogordo Bombing Range in New Mexico, United States. The test blast created temperatures 10,000 times the surface temperature of the sun and was felt 200 miles away. The explosion was the equivalent of 20,000 tons of TNT and throws a column of fire and smoke 35,000 feet into the night sky. The authorities hid the blast by claiming that an ammunition dump had gone up.|
|24 Jul 1945||US President Harry Truman informed Soviet leader Joseph Stalin that the United States had successfully constructed atomic weapons. Stalin showed surprise, but in actuality he had already learned this through the Soviet intelligence network.|
|12 Aug 1945||The Smyth Report, written by American physicist Henry DeWolf Smyth, with the history of the development of the atomic weapons, was released to the public.|
|17 Oct 1945||Norris Bradbury succeeded Robert Oppenheimer as the director of the Los Alamos, New Mexico, United States facility of the Manhattan Project.|
|10 Nov 1945||United States Secretary of War Robert Patterson ordered all cyclotrons in Japan destroyed.|
|24 Nov 1945||Per orders of United States Secretary of War Robert Patterson, all cyclotrons in Japan were destroyed.|
|1 Jan 1947||The Atomic Energy Act of 1946, signed into American law by US President Harry Truman on 1 Aug 1946, came into effect. Manhattan Project was thus turned over to the newly established civilian United States Atomic Energy Commission.|
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