Gas-Discharge Counters of Ionizing Radiation
The Geiger-Muller counter, a gas-discharge device for detection and research of different radioactive and other ionizing radiation: alpha and beta particles, gamma quanta, light and x-ray quanta, particles of high energy in cosmic rays and on accelerators.
The counter is intended for work in various dosimetric and radiometric devices.
The counters are classified according to the following characteristics:
1. By type of traceable radiation:
- counters of alpha-radiation;
- counters of beta-radiation;
- counters of gamma-radiation;
- neutron counters;
- counters of x-ray radiation;
- counters of ultraviolet radiation (photons).
2. By the constructive design:
- end (the input window on the end of the device);
- cylindrical, with the side input window;
- internal filling.
3.By the method of discharge extinguishing:
- not being self-extinguished in which the discharge is broken off by means of external radio engineering scheme elements;
- being self-extinguished in which the discharge is broken off by means of gas discharge mechanism in the counter.
Requirements to Counters
Depending on the operating conditions of the equipment, in which the counters of ionizing radiation are applied, the latter should be resistant to the effects of various mechanical (vibration, single and multiple strikes) and climate (high and low temperature, high and low pressure, humidity) factors.
Advanced technologies, used in the manufacture of counters, use of high-quality materials, alloys, television mica, gases of high purity and careful production control, ensure the stability of electrical and radiometric parameters of counters, high reliability and durability of their work in the equipment.
Guidelines on the Counters Treatment and Operation
Counters of ionizing radiation should be handled with care during their installation in the equipment. Protect counters from shock and mechanical damage. This applies particularly to the counters with input mica windows. A mica window cannot be touched with hands and must be protected from damage and punctures. Do not allow any kinds of pollution to get on the counter as it leads to the deterioration of the insulation properties. You cannot bend output closer than 6 mm from the casing or isolator.
Failure to observe the polarity of the turning on of the counter can lead to its damage, even if this voltage is supplied for a short period of time.
The counters with organic extinguishing additive are especially sensitive to overloading on both voltage and counting speed.
The excess of the operating voltage and the maximum allowed counting speed lead to a drastic reduction in the service life of the device. The operation of all types of counters with two or more maximum permissible values of the electric and radiometric parameters is not allowed.
To evaluate the quality of the counters at an input control of electric and radiometric parameters, it is enough to verify the slope of the plateau, the amplitude spectrum of the pulse.