Time projection chamber

In physics, a Time Projection Chamber is a particle detector invented by David R. Nygren at Lawrence Berkeley Laboratory.cite web|url = http://www.er.doe.gov/Lawrence/html/Laureates/1980s/davidr.htm|title = The Ernest Orlando Lawrence Award: 1980's Laureates|accessdate = 2007-08-18|publisher = Department of Energy|quote = David R. Nygren, 1985: Physics: For the development of experimental techniques in particle physics and especially for the invention of the Time Projection Chamber.] A time projection chamber consists of a gas-filled cylindrical chamber with multiwire proportional chambers (MWPC) as endplates. Along its length, the chamber is divided into halves by means of a central high voltage electrode disc, which establishes an electric field between the center and the endplates. Furthermore, a magnetic field is often applied along the length of the cylinder, parallel to the electric field, in order to minimize the diffusion of the electrons coming from the ionization of the gas. On passing through the detector gas a particle will produce primary ionization along its track. The $z$-coordinate, the coordinate along the cylinder axis, is determined by measuring the drift time from the ionization event to the MWPC at the end. This is done using the usual technique of a drift chamber. The MWPC at the end is arranged with the anode wires in the azimuthal direction, $heta$, which provides information on the radial coordinate, $r$. To obtain the azimuthal direction, each cathode plane is divided into strips along the radial direction.

References

External links

* [http://www.cerncourier.com/main/article/44/1/26 The time projection chamber turns 25] , CERN Courier, Volume 44 (2004), Issue 1
* [http://www.lbl.gov/Science-Articles/Archive/star/index.html Back to the Beginning, The Time Projection Chamber] , Sciencebeat, February 22, 1999