Proportional chamber

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

The analyzing magnet in conjunction with the multi-wire proportional chamber planes, was used to measure the momenta of charged particles. The shower counters and scintillation counters, installed after the iron absorbers, identified electrons and muons accordingly. After the introduction of a set of criteria, 320 examples of the decay (1) were observed. By imposing more strict criteria, from this number, 163 events were selected [3],... 

X-ray diffraction measurements were carried out using KARD-6 diffractometer with a 2D-area detector based on the multi-wire planar proportional chamber (Cu K -radiation, graphite monochromator, 0.1mm width incident beam slit). 

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... 

In a proportional chamber, which has a coaxial cylindrical configuration as shown in Fig. 1 a, the field has a radial distribution, and is given by. 

In order to derive an expression for the gas amplification in the proportional chamber type of detector, the integration of the general form (5) has to be carried out for the special case of this radial field distribution. 

The Diethorn expression has been applied in a detailed analysis of commercially available proportional chambers by R. W. Hendricks Fig. 2 shows the test results for a series of counters, the parameters of which are given in Table I. The tested devices are not position sensitive detectors, but normal cylindrical proportional counters. 

In multi-wire proportional chamber systems (MWPC-systems), and also in linear position sensitive detectors, the cathode electrodes are usually divided up into individual strips, from which the positional information can be extracted. 

Fig. 12. The electric field in a multi-wire proportional chamber. (From Ref.

The last term in expression (3) can be neglected. From the result in Fig. (15) one calculates an amplification factor exp (ad) = 2,5-10. This value is comparable with the gain achieved in classical multi-wire proportional chambers. 

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... 

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. 

Increased sensitivity because of the high specific ionization produced in the gas-filled proportional chamber using argon/methane (89 10)... 

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. 

Mulitwire proportional chambers (MWPC) have been developed for use as position-sensitive focal detectors for magnetic spectrometers. They can provide excellent position resolution, operate with counting rates as high as 10 counts/s, and provide a large solid angle at the focal plane of the spectrometer. 

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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