In a Geiger-Müller tube, or Geiger counter, incoming X-ray photons ionize atoms in a gas-filled volume. An applied high voltage induces further ionizations from collisions between liberated electrons and neutral atoms, creating an avalanche of charged particles and a large electrical pulse that is easily detected.
Read moreHow are x-rays naturally produced?
X-rays and gamma rays can come from natural sources, such as radon gas, radioactive elements in the earth, and cosmic rays that hit the earth from outer space .
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