What does a Geiger-Müller counter measure?

A Geiger-Müller counter is an instrument designed specifically to detect and measure ionizing radiation. This type of radiation includes alpha particles, beta particles, and gamma rays, all of which are capable of displacing electrons from atoms and causing ionization. The Geiger-Müller counter operates by using a gas-filled tube that detects ionization events; when radiation passes through the tube, it ionizes the gas, leading to a measurable electrical pulse that can be counted.

The ability to measure a range of ionizing radiation, rather than just one type, allows for a comprehensive understanding of radiation exposure and safety levels. This is crucial in various applications, including health physics, environmental monitoring, and radiation protection, where knowing the full spectrum of ionizing radiation present is essential for safety and regulatory compliance.