Linear particle accelerator: Difference between revisions

Revision as of 00:51, 1 September 2023

Revision as of 03:45, 3 November 2023

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[[File:Wideroe linac en.svg|thumb|300px|Wideroe's linac concept. The voltage from an RF source is connected to a series of tubes which shield the particle between gaps.]]

[[File:CERN Linac1.jpg|thumb|Alvarez type linac]]

In 1924, Gustav Ising published the first description of a linear particle accelerator, using a series of accelerating gaps. Particles would proceed down a series of tubes. At a regular frequency, an accelerating voltage would be applied across each gap. As the particles gained speed while the frequency remained constant, the gaps would be spaced farther and farther apart, in order to ensure the particle would see a voltage applied as it reached each gap. Ising never successfully implemented this design.<ref name="heibron">{{cite book |last1=Heilbron |first1=J.L. |last2=Seidel |first2=Robert W. |title=Lawrence and His Laboratory: A History of the Lawrence Berkeley Laboratory, Volume I |date=1989 |publisher=University of California Press |___location=Berkeley, CA |url=http://ark.cdlib.org/ark:/13030/ft5s200764/ |access-date=2 February 2022}}</ref>

[[Rolf Wideroe]] discovered Ising's paper in 1927, and as part of his PhD thesis, built an 88-inch long, two gap version of the device. Where Ising had proposed a spark gap as the voltage source, Wideroe used a 25kV [[vacuum tube]] oscillator. He successfully demonstrated that he had accelerated sodium and potassium ions to an energy of 50 thousand [[electron volt]]s (50 keV), twice the energy they would have received if accelerated only once by the tube. By successfully accelerating a particle multiple times using the same voltage source, Wideroe demonstrated the utility of [[radio frequency]] acceleration.<ref>{{cite book |last1=Conte |first1=Mario |last2=MacKay |first2=William |title=An introduction to the physics of particle accelerators |date=2008 |publisher=World Scientific |___location=Hackensack, N.J. |isbn=9789812779601 |edition=2nd}}</ref>