Geiger-Muller detectors detect which types of radiation?

• A. X-ray and Gamma
• B. Alpha, Beta, and Gamma
• C. Beta and Gamma
• D. Alpha only

Answer: (B)

Geiger-Muller detectors detect ionizing events in a gas-filled chamber, which allows them to respond to a wide range of radiation types. They are sensitive to charged particles and to photons that ultimately produce ionization in the gas. Alpha particles, though short-ranged, are highly ionizing and will trigger a pulse if the source is nearby or the window is thin enough for the particle to enter the tube. Beta particles, being charged, also ionize the gas and generate pulses as they pass through. Gamma rays, while uncharged, interact with surrounding matter to produce fast electrons (via Compton scattering or the photoelectric effect); those electrons then ionize the gas and create pulses in the detector. Because of this mechanism, Geiger-Muller detectors are used to detect alpha, beta, and gamma radiation, though their efficiency for each type varies and they do not provide energy information.