Charpak drift chamber connected to electronics box
date: label: Date made
content: 1969
name: label: maker
content: Charpak, G.
notes: label: Description
content: This object consists of two drift chamber assemblies attached to an electronic box. The two drift chamber assemblies have green plastic walls and transparent plastic windows, in metallic frames with parallel wires running horizontally in the first window and vertically in the second. They are attached to a single perforated metallic covered preamp. The latter assembly is attached on one side to rectangular, metal-enclosed, box for electronics. Wires connect the drift chamber assembly to one side of electronics box. Two high voltage cable receptacles protrude on opposite side of electronics box near top edge.
label: Description
content: Basic Principles and History
label: Description
content: A wire chamber is a chamber with many parallel wires, arranged as a grid and put on high voltage, with the metal casing being on ground potential. As in the Geiger counter, a particle leaves a trace of ions and electrons, which drift toward the case or the nearest wire, respectively. By marking off the wires which had a pulse of current, one can see the particle's path. If one also precisely measures the timing of the current pulses of the wires and takes into account that the ions need some time to drift to the nearest wire, one can infer the distance at which the particle passed the wire. This greatly increases the accuracy of the path reconstruction and is known as a drift chamber.
label: Description
content: While testing their newly developed multiwire proportional chamber (see Object ID no. 1977.0708.02), Charpak and his collaborators found that the difference in arrival times of electrons at adjacent wires, they could quickly estimate just where between the two wires an ionizing particle had passed. They showed that this principle of location - - measuring the time for electrons to drift from the point where produced to a sensing wire - - could be extended from one or two millimeters to many centimeters. The essential refinement was the addition of “field shaping” wires which, by producing a uniform electric field, ensured a constant drift velocity of the electrons. In practice, the drift chamber must be preceded or followed by a counter to mark the starting time of the drifting electrons.
label: Description
content: In 1992 Charpak received the Nobel Prize for Physics in acknowledgment of his invention of the MWPC, an electronic particle detector that revolutionized high-energy physics experiments and has had applications in medical physics.
label: Description
content: For additional technical information, see:
label: Description
content: http://www.nobelprize.org/nobel_prizes/physics/laureates/1992/charpak-lecture.pdf and,
label: Description
content: http://cds.cern.ch/record/117989/files/CERN-77-09.pdf?bcsi_scan_2687365ababd2c82=b3SiuvtOAg0NfXwMHl9pO/npSm4KAAAArlNvLw==&bcsi_scan_filename=CERN-77-09.pdf
label: Location
content: Currently not on view
topic: label: general subject association
content: Science & Scientific Instruments
setName: label: See more items in
content: Medicine and Science: Modern Physics
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content: Energy & Power
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content: Science & Mathematics
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content: Modern Physics
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content: Measuring & Mapping
creditLine: label: Credit Line
content: European Organization for Nuclear Research (CERN)
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1977.0708.01
label: catalog number
content: 1977.0708.01
label: accession number
content: 1977.0708
objectType: label: Object Name
content: Chamber, Drift
physicalDescription: label: Physical Description
content: plastic; metal (overall material)
label: Measurements
content: drift chamber: 13 cm x 16 cm x 9 cm; 5 1/8 in x 6 5/16 in x 3 17/32 in
label: Measurements
content: electronics box: 20 cm x 16 cm x 10 cm; 7 7/8 in x 6 5/16 in x 3 15/16 in