Multiwire chamber

Charpak, G. (1988). Some applications of multiwire chambers to the detection of electromagnetic radiations. Nud. Inst. Methods 269,341A345. 

G. Charpak (ficole Superieure de Physique et Chemie, Paris, and CERN Geneva) invention and development of particle detectors, in particular the multiwire proportional chamber. 

More recent versions of this design feature an added focusing system, called a radial drift chamber, in front of the detector. Gas ionization occurs within this drift chamber, which is composed of a set of concentric charged rings sandwiched between two lens-shaped metal grids. The cluster of electrons is then focused by the drift chamber, making its direction normal to the surface of the multiwire detector. 

The basic principle of operation of gas filled detectors, be it multiwire proportional chambers or linear devices, with a single anode wire, is the mechanism of gas amplification. This kind of detectors have — as its name implies, a filling of an... 

Photon counting devices are required in order to arrive at the necessary accuracy. The noise of the detector has to be lower than 4 orders of magnitude with respect to the signal. Our experience with multiwire proportional chambers may let us believe that this rather stringent condition can be fulfilled. The simultaneous measurement of the whole scattering pattern by position sensitive area detectors is absolutely mandatory... 

Three types of area detectors are presently used in macromolecular crystallographic research (1) multiwire proportional counters, (2) television area detectors, and (3) imaging plates. A multiwire proportional counter consists of an anode between two cathodes these consist of arrays of parallel wires and are arranged perpendicular to each other. The chamber is filled with a gas, consisting partly of xenon which is ionized by the incident X rays, an effect recorded by the detecting device. Television area detectors contain a fluorescent phosphor that produces visible light when hit by an X-ray beam. After intensification, the photons are detected by a television photocathode. 

CHA 70] CHARPAK G., RAHN D., STEINER H., Some developments in the operation of multiwire proportional chambers , VucZ. Instrum. Meth., vol. 80, p. 13-34, 1970. 

The first magnetic spectrometers used photographic plates for the detection of the deflected particles. Today, position-sensitive semiconductor detectors or multiwire proportional chambers are used (see Sec. 13.10). These detectors are better than photographic plates because they have the capability of on-line data collection, provide time information for coincidence experiments, and measure the energy of the particle. 

The telescope ART-P aboard Granat was designed for imaging and spectroscopy in the 2.5-60 keV energy band (Sunyaev et al., 1990). It consists of a position sensitive detector (a multiwire proportional chamber with a window area of 625 cm ) equipped with a URA coded mask and a collimator. 

Radioactive zones can be detected on thin layers by film autoradiography, digital autoradiography with a multiwire proportional chamber, use of charged-coupled devices, or bioimaging/phosphor imaging techniques. These methods differ in terms of factors such as simplicity, speed, sensitivity, resolution, linear range, and accuracy and precision of quantification, and the method of choice depends on the available instrumentation, the type of experiment, and the information needed. 

The CSCs are trapezoidal shaped multiwire proportional chambers which consist of 6 anode wire planes crossed with 7 copper strips cathode panels in a gas volume. They provide a two-dimensional position measurement, where the r and (p coordinates are determined by the copper strips and the anode wires, respectively. The muon detector endcaps consist of 4 CSC stations on each side and identify muons in the pseudorapidity range of 0.9 < V < 2.4. 

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