Geiger-miller counters are made based on the ability of rays to ionize gases and are the most commonly used type of wire counter. There is a low-voltage gas stored in a metal tube closed with insulating material at both ends, and a metal wire is installed along the axis of the tube. A battery pack is used to produce a certain voltage between the metal wire and the tube wall (slightly lower than the breakdown voltage of the gas in the tube). When no ray passes through the tube, the gas does not discharge. When a high-speed particle of a certain ray enters the tube, it can ionize the gas atoms in the tube, release a few free electrons, and fly to the wire under the action of a voltage. Along the way, these electrons ionize other atoms of the gas, releasing more electrons. More and more electrons then ionize more and more gas atoms in succession, and finally make the gas in the tube become a conductor, resulting in a rapid gas discharge between the filament and the tube wall. Thus a pulse current is fed into the amplifier and received by a counter connected to the amplifier output. The counter automatically records the discharge of each particle as it flies into the tube, so the number of particles can be detected.

Geiger-muller counters are widely used in a variety of radiation-related industries, civil daily protection, medical, food, chemical, nuclear power plants, etc.

The Geiger-Miller counter is the core sensor, and after appropriate circuit design and signal processing, the detector can be developed for different application environments.