GeigerMüllerZählrohren

GeigerMüllerZählrohren, often shortened to GM counters, are instruments used for detecting and measuring ionizing radiation. They are a type of gas-filled detector that operates by utilizing the ionization of a gas within a sealed tube. The tube contains a central electrode, typically a wire, surrounded by a cylindrical cathode. A high voltage is applied between these electrodes. When ionizing radiation, such as alpha particles, beta particles, or gamma rays, enters the tube, it interacts with the gas inside, causing ionization. This ionization creates electron-ion pairs. The high voltage accelerates these ions and electrons, leading to a cascade of further ionizations, known as an avalanche. This avalanche produces a detectable electrical pulse, which is then amplified and registered by a counting circuit. Each pulse corresponds to a single ionizing event detected by the tube. The rate of these pulses, often displayed as counts per minute (CPM) or counts per second (CPS), provides a measure of the radiation intensity. GM counters are widely used in various fields, including nuclear physics, radiation protection, environmental monitoring, and homeland security, due to their sensitivity and relatively low cost. However, they generally cannot distinguish between different types of radiation or measure their energy.