A Geiger counter is a device used to detect and measure ionizing radiation, such as alpha particles, beta particles, and gamma rays. It consists of a Geiger-Müller tube, which produces an electrical pulse when radiation passes through it. This pulse is then counted and displayed, often in counts per minute (CPM), allowing users to assess radiation levels in their environment. Geiger counters are commonly used in various fields, including nuclear industry, environmental monitoring, and health physics. They help ensure safety by detecting radiation exposure, which can be harmful to human health. Understanding radiation levels is crucial for protecting both people and the environment from potential hazards.