The Geiger-Miller counter, or Geiger counter for short, is a counting instrument designed to detect the intensity of ionizing radiation (alpha particles, beta particles, gamma rays, and X-rays). When the voltage applied to the probe reaches a certain range, each pair of ions ionized by the ray in the tube can be amplified to produce an electrical pulse of the same size and recorded by the connected electronic device, thus measuring the number of rays per unit time.