Calutron

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Schematic diagram of uranium isotope separation in the calutron.

Control panels and operators for calutrons at the Oak Ridge Y-12 Plant. During the Manhattan Project the operators, mostly women, worked in shifts covering 24 hours a day. Gladys Owens, the woman seated at right closest to the camera, was unaware of the purpose and consequence of her work until seeing the photo of herself while taking a public tour of the facility nearly 60 years later.[1]

A Calutron was a mass spectrometer used for separating the isotopes of uranium developed by Ernest O. Lawrence during the Manhattan Project and was similar to the Cyclotron invented by Laurence. Its name is a concatenation of Cal. U.-tron, in tribute to the University of California, Lawrence's institution and the contractor of the Los Alamos laboratory. 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.

In a mass spectrometer, a vaporised quantity of a sample is bombarded with high energy electrons which causes them to become positively charged ions. They are then accelerated and subsequently deflected by magnetic fields. They then collide with a plate, producing a measurable electric current. The mass of the ions can be calculated according to the strength of the field and the charge of the ions.

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. 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. Due to the copper shortage during WWII, the electromagnets were made from thousands of tons of silver borrowed from the U.S. Treasury.^[1].

After the 1990 Gulf War, UNSCOM determined that Iraq had been pursuing a calutron program to enrich uranium.^[2]