Different Types of Gas-Filled Detectors

Proportional counters operate in region III. Charge multiplication takes place, but the output signal is still proportional to the energy deposited in the counter. Measurement of particle energy is possible. Proportional counters may be used for the detection of any charged particle. 

Gas counters may be constructed in any of three basic geometries parallel plate, cylindrical, or spherical (Fig. 5.5). In a parallel-plate chamber, the electric field (neglecting edge effects) is uniform, with strength equal to 

In the (ylindrical chamber, the voltage is applied to a very thin wire, a few mills of an inch in diameter, stretched axially at the center of the cylinder. The cylinder wall is usually grounded. The electric field is, in this case. 

A counter filled with a gas at a certain pressure may operate in any of the regions I-IV discussed earlier, depending on a combination of the following 

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