A Calutron was a mass spectrometer used for separating the isotopes of uranium developed by Ernest O. Lawrence[1] during the Manhattan Project and was similar to the Cyclotron invented by Lawrence. Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles Isotope separation is the process of concentrating specific Isotopes of a Chemical element by removing other isotopes for example separating Natural uranium Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Ernest Orlando Lawrence ( August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb A cyclotron is a type of Particle accelerator. Cyclotrons accelerate Charged particles using a high- Frequency, alternating Voltage (potential Its name is a concatenation of Cal. For concatenation of general lists see Append. In Computer programming, string concatenation is the operation of joining two character U. -tron, in tribute to the University of California, Lawrence's institution and the contractor of the Los Alamos laboratory. The University of California ( UC) is a Public university system in the state of California. Los Alamos National Laboratory (LANL (previously known at various times as Site Y, Los Alamos Laboratory, and Los Alamos Scientific Laboratory) is a [2] They were implemented for industrial scale uranium enrichment at the Oak Ridge, Tennessee Y-12 plant established during the war and provided much of the uranium used for the "Little Boy" nuclear weapon, which was dropped onto Hiroshima in 1945. Enriched uranium is a kind of Uranium in which the percent composition of Uranium-235 has been increased through the process of Isotope separation. Oak Ridge is an incorporated City in Anderson and Roane Counties in East Tennessee, USA, about 25 miles northwest of The Y-12 National Security Complex is a United States Department of Energy National Nuclear Security Administration facility located in Oak Ridge Tennessee Little Boy was the Codename of the Atomic bomb, developed via the "Manhattan Project" which was dropped on Hiroshima, on August 6 1945 by the A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar
In a mass spectrometer, a vaporised quantity of a sample is bombarded with high energy electrons which causes them to become positively charged ions. Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge They are then accelerated and subsequently deflected by magnetic fields. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges They then collide with a plate, producing a measurable electric current. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. The mass of the ions can be calculated according to the strength of the field and the charge of the ions. Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object
To maximize the separation and the use of the required large electromagnet, multiple Calutrons were arranged around the magnet in a massive oval, which resembled (and were called) race tracks. In geometry an oval or ovoid (from Latin ovum, 'egg' is any Curve resembling an egg or an Ellipse. A race track (or 'racetrack' or 'racing track' is a purpose-built facility for Racing of animals (eg Two types of Calutrons were created, known as Alpha and Beta, as the technology was improved. Magnetic separation was later abandoned in favor of the more complicated, but more effective, gaseous diffusion method. Gaseous diffusion is a technology used to produce Enriched uranium by forcing gaseous Uranium hexafluoride, UF6 through semi-permeable membranes Due to the copper shortage during WWII, the electromagnets were made from thousands of tons of silver borrowed from the U. S. Treasury. [3][4]
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Uranium isotope separation
The world did not lack methods for separating isotopes when it discovered the possible utility of a kilogram of uranium-235 (235U). Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Uranium-235 is an isotope of uranium that differs from the element's other common isotope Uranium-238, by its ability to cause a rapidly expanding fission Known techniques, pursued simultaneously in Germany and the United States, included ultra-centrifugation, diffusion across thermal or osmotic pressure barriers, and deflection in electric and magnetic fields. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The United States of America —commonly referred to as the The ultracentrifuge is a Centrifuge optimized for spinning a rotor at very high speeds capable of generating acceleration as high as 1000000 g (9800 km/s² Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement Osmosis is the Diffusion of a solvent (frequently water through a semi-permeable membrane, from a solution of low solute concentration (high water potential In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. The last method appealed to Lawrence, who had made his reputation on the precise control of beams of charged particles. In principle the technique is simple. When passing between the poles of a magnet, a monoenergetic beam of ions of naturally occurring uranium splits into several streams according to their momentum, one per isotope, each characterized by a particular radius of curvature. Collecting cups at the ends of the semicircular trajectories catch the homogeneous streams.
Most physicists in 1941 doubted that electromagnetic separation would succeed in practice because they expected that the mutual repulsion of the like-charged ions (the space charge effect) would prevent the formation of narrow beams. Space charge is a concept in which excess Electric charge is treated as being a Continuum of charge distributed over a region of space (either a volume or an area But Lawrence, who had seen a line of positively charged ions pour from his cyclotron, guessed that negative particles formed in the air kept the beam from dispersing under its own electrical influence. He had the 37-inch (94 cm) cyclotron modified to demonstrate the feasibility of electromagnetic separation of uranium isotopes using the principle of the mass spectrograph. Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles "It will not be a calamity," he wrote Compton, if uranium turned out to have no military applications; but if "fantastically positive and we fail to get them first, the results for our country may well be a tragic disaster. " By December 1941 the uranium ion beam was passing 5 microamperes to the collector; a small amount to be sure, but enough to assure Lawrence that space charge would not be a formidable problem.
The fact that beams of uranium ions could be defined well enough to yield small quantities of isotopes suitable for laboratory research by no means assured that electromagnetic separation could be worked on the industrial scale necessary to make a kilogram of 235U. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides The process has little to work on, only the slight difference in mass-1. 25 percent-between uraniums 235 and 238. Because the lighter ions respond slightly more readily to the magnetic field than the heavier, their trajectories bend in a tighter arc. At the end of their semicircular travel, the ions of 235U are relatively more plentiful on the inside than on the outside of the beam. But the maximum separation even in the ideal case is small, only one-tenth inch for an arc with a diameter of 37 inches (94 cm). Actual beams are far from ideal.
The alpha calutron
Many technical problems had to be solved before even a prototype could be tested in the field of the nearly completed 184-inch (4. Frank Friedman Oppenheimer ( August 14, 1912 &ndash February 3, 1985) was an American Physicist who worked on the Robert Lyster Thornton (November 29 1908 - September 28 1985 was born at Wooton Bedfordshire, England, the son of a mechanical engineer Dudley L 67 m) magnet. The beams, though small, could melt the collectors during long hours of operation; the staff therefore installed water cooling for the collectors and tank liner. They contrived electric arcs to ionize the uranium tetrachloride feed. An electric arc is an Electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive Uranium tetrachloride (UCl4 is a dark green compound of Uranium. They devised ways to extract the enriched uranium that collected at the receiver, and the still valuable feed material that condensed along with chloride "gunk" (to use their technical term) all over the inside of the tank. The chloride Ion is formed when the element Chlorine picks up one Electron to form an Anion (negatively-charged ion Cl&minus They made scrapers to clean the exit slits of the feed sources regularly lest the accumulated "crud" (another word of art) cut down beam strength. Lawrence's optimistic conclusion: by the fall of 1942 ten calutrons, each with a 100-milliampere source and all operating within the 184-inch field, would produce four grams of enriched uranium a day. Enriched uranium is a kind of Uranium in which the percent composition of Uranium-235 has been increased through the process of Isotope separation. The S-1 Uranium Committee that oversaw the uranium project for Office of Scientific Research and Development recommended expending $12 million to create a plant with 25 times that capacity before the fall of 1943. The S-1 Uranium Committee was a Committee of the National Defense Research Committee that superseded the Briggs Advisory Committee on Uranium and later evolved into The Office of Scientific Research and Development (OSRD was an agency of the United States federal government created to coordinate scientific research for military purposes Lawrence did not doubt that other means, particularly reactor production of fissile plutonium, might ultimately be the most efficient way to a bomb. In Nuclear engineering, a fissile material is one that is capable of sustaining a Chain reaction of Nuclear fission. But in mid-1942 no reactor worked, and the calutron did.
The calutron design settled on in 1942, called "alpha," provided for enrichment of natural uranium to about 15 percent 235U. Extravagant effort went into designing powerful ion sources and aptly shaped, eventually parabolic collecting slots. In Mathematics, the parabola (pəˈræbələ from the Greek παραβολή) is a Conic section, the intersection of a right circular The many modifications and security codes proliferated whimsical names: sources Plato, Cyclops, Bicyclops, and Goofy mated with receivers Gloria, Irene, Mona, or Zulu. Ions from Plato and his friends traversed an arc 48 inches (1. 22 m) in radius to reach collector slits placed 0. 6 inch (15 mm) apart. The guiding magnetic field was shimmed not by the old black art but in obedience to calculations. Accurately machined and installed, the shims greatly increased the usable beam that reached the collectors.
Scaling up at Oak Ridge
Among results obtained with the 184-inch magnet was a design superior to it for large-scale calutrons, the so-called "XA. " The prototype of the magnets to be installed at Oak Ridge, XA was a rectangular, three-coil magnet giving a horizontal field in which the calutron tanks could stand side-by-side. Oak Ridge National Laboratory ( ORNL) is a multiprogram science and technology National laboratory managed for the United States Department of Energy by It had room for four alpha tanks, each with a double source. By the spring of 1943, convinced that the Germans might be ahead, General Leslie Groves decided to skip the scheduled pilot plant; from the XA and a scale model of the production magnet alone would come procedures for alpha operation at Oak Ridge. Lieutenant General Leslie Richard Groves ( August 17, 1896 &ndash July 13, 1970) was a United States Army Engineer Tests of the first, full-scale system installed there, the XAX, were scheduled for July.
The spring and early summer of 1943 brought hundreds of trainees to Berkeley from Tennessee- Eastman Company, the operator for the Oak Ridge plant. The Laboratory labored to ensure that the test XA magnet system and alpha units were working by April in spite of delays in delivery of steel. Between April and July the training sessions ran continuously. In June a migration that by 1944 would reach 200 started for Oak Ridge. Laboratory expenditures exceeded half a million dollars a month.
The first wave of Berkeley workers at Oak Ridge had to see that the XAX magnet worked. The University of California Berkeley (also referred to as Cal, Berkeley and UC Berkeley) is a major research university located in Berkeley Then runs could begin on the first production system, or "racetrack;" a 24-fold magnification of the XA that could hold 96 calutron alpha tanks. To minimize magnetic losses and steel consumption, the assembly was curved into an oval 122 feet (37 m) long, 77 feet (23 m) wide and 15 feet (4. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 6 m) high. Want of copper for the large coils to produce the magnetic fields prompted a solution possible only in wartime: Groves drafted 14,700 tons (13,300 tonne) of pure silver from a government vault for the purpose. Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen Late in the summer of 1943 the XAX was ready for testing. After a week of difficulty, it cleared the hurdle for full-scale racetrack runs.
The first two of five projected racetracks started up in November and failed from contaminated cooling oil; the second was limping in January, but produced 200 grams of uranium enriched to 12 percent 235U by the end of February 1944, its fifth of the total goal of one kilogram of enriched uranium per month. By April four racetracks were functioning, including the repaired number 1. They required constant attention. Many people from the Laboratory helped modify the units to reach production goals.
The calutrons were initially operated by scientists from Berkeley to remove bugs and achieve a reasonable operating rate. Then Tennessee Eastman operators who had only a high school education took over. Kenneth Nichols compared unit production data, and pointed out to Ernest Lawrence that the young “hill-billy” girl operators were outproducing his Ph. Kenneth David Nichols ( 13 November 1907 – 21 February 2000) was the deputy to General Leslie Groves in the American project to develop Ernest Orlando Lawrence ( August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his Ds. They agreed to a production race and Lawrence lost, a morale boost for the Tennessee Eastman workers and supervisors. The girls were trained like soldiers not to reason why, while “the scientists could not refrain from time-consuming investigation of the cause of even minor fluctuations of the dials” [6] Responsibility for operation passed entirely to Tennessee Eastman after the spring of 1944, and the Laboratory staff at Oak Ridge turned their attention to redesigning the calutron system for higher efficiency. Eastman Chemical Company is a United States based Chemical company, engaged in the manufacture and sale of chemicals plastics and fibers
The beta calutrons
Many at the Laboratory, especially Edward Lofgren and Martin Kamen, thought that a second stage would be necessary to reach the required enrichment. Edward J Lofgren was an American physicist in the early days of elementary particle research at the Lawrence Berkeley Laboratory (LBL Martin David Kamen ( August 27, 1913, Toronto &ndash August 31, 2002) was co-discoverer (with Sam Ruben) of the Isotope Groves approved the idea. In the spring of 1943, during training at Berkeley for alpha operations, design began on the second or beta stage. Because beta would have only the enriched product of alpha as feed, it would process proportionately less material; its beam therefore did not need to be as broad, nor its dimensions as large, as alpha's. Beta design emphasized recovery, not only of the further enriched output but also of the already enriched feed. The first units were tried at Oak Ridge in late February 1944, but the sources had to be redesigned, and even by June difficulties persisted in recovering the precious beta feed strewn throughout the calutron. Process efficiencies stayed low: only 4 or 5 percent of the 235U in the feed ended up in the output. A better source of enriched uranium feed would have to be found to create the 10 kilograms or so of 90 percent 235U that Robert Oppenheimer thought necessary for a bomb.
The gaseous diffusion procedure for separation of uranium isotopes, which had consumed more money even than the calutron, had not met its design goals by late 1944. Gaseous diffusion is a technology used to produce Enriched uranium by forcing gaseous Uranium hexafluoride, UF6 through semi-permeable membranes Groves decided that it could not be counted on to produce high enrichment, and that whatever it did produce would have to be supplemented with other slightly enriched uranium and processed through beta calutrons. To augment the calutron feed, the Manhattan Engineering District constructed still another plant at Oak Ridge, this one working by thermal diffusion, a method developed by Philip Abelson. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb Philip Hauge Abelson ( April 27, 1913 – August 1, 2004) was an American Physicist, editor of scientific literature and
Weapons grade uranium
In the critical production period in the first months of 1945, the calutrons, particularly the six betas of 36 tanks each, produced weapons-grade 235U using feed from the modified alpha calutrons, the small output from the gaseous diffusion plant, and whatever the new thermal process had to offer. Virtually all the 235U sent by courier on the train to Chicago and on to Los Alamos, New Mexico had passed through the beta calutrons. Chicago (ʃɪˈkɑːgoʊ is the largest City by population in the state of Illinois and the American Midwest of the United States. Los Alamos (Los Álamos meaning "The Cottonwoods quot is a Townsite and Census-designated place (CDP in Los Alamos County, From these shipments Oppenheimer's physicists assembled the bomb that was to destroy Hiroshima. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's
Modern calutrons
After the 1990 Gulf War, UNSCOM determined that Iraq had been pursuing a calutron program to enrich uranium. United Nations Special Commission ( UNSCOM) was an inspection regime created by the United Nations to ensure Iraq 's compliance with policies concerning [7]
Calutron patents
The main Calutron patents are Methods of and apparatus for separating materials (Ernest O. Lawrence),[8] Magnetic shims (Robert Oppenheimer and Stanley Frankel),[9] and Calutron system (Ernest O. Lawrence). Ernest Orlando Lawrence ( August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his Stanley Phillips "Stan" Frankel (1919 – May 1978 was an American computer scientist Ernest Orlando Lawrence ( August 8, 1901 – August 27, 1958) was an American physicist and Nobel Laureate best known for his [10]
See also
References
- ^ Lawrence and His Laborator. Lesnoy (Лесно́й is a closed town in Sverdlovsk Oblast, Russia, located north of Yekaterinburg on the banks of the LBL Newsmagazine. Lawrence Berkeley Lab (1981). Retrieved on 2007-09-03. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 36 BC - In the Battle of Naulochus, Marcus Vipsanius Agrippa, Admiral of Octavian, defeats Sextus Pompeius
- ^ Parkins, William E. (2005 May 01). "The Uranium Bomb, the Calutron, and the Space-Charge Problem". Physics Today 58 (5): 45-51. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. |url=http://masspec.scripps.edu/MSHistory/timelines/time_pdf/1947_ParkinsWE.pdf|format=PDF|accessdate=2007-09-01
- ^ "THE SILVER LINING OF THE CALUTRONS", ORNL Review, Oak Ridge National Lab, 2002. Retrieved on 2007-11-30. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1700 - Battle of Narva — A Swedish army of 8500 men under Charles XII defeats
- ^ Smith, D. Ray. "Miller, key to obtaining 14,700 tons of silver Manhattan Project", Oak Ridger, 2006. Retrieved on 2007-11-30. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1700 - Battle of Narva — A Swedish army of 8500 men under Charles XII defeats
- ^ Smith, D. Ray. The Calutron Girls. Retrieved on 2007-09-01. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 462 - Possible start of first Byzantine indiction cycle.
- ^ Nichols, Kenneth D. ‘’The Road to Trinity page 131 (1987, Morrow, New York) ISBN 068806910X
- ^ William Langewiesche, Point of No Return, Atlantic Magazine, Jan/Feb 2006, p107, citing the work of Mark Hibbs, Nucleonics Week, 1992.
- ^ US patent 2709222
- ^ US patent 2719924
- ^ US patent 2847576
External links
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- This article incorporates text from Lawrence and His Laboratory: The Calutron, a public domain work of the United States Government. The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone A work of the United States government, as defined by United States copyright law, is "a work prepared by an officer or employee of the U
- This article incorporates text from The Manhattan Project: An Interactive History, a public domain work of the United States Government. The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone A work of the United States government, as defined by United States copyright law, is "a work prepared by an officer or employee of the U
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