The Ludlum 2241 is used to measure which type of radiation?

• A. Gamma
• B. Alpha
• C. Beta
• D. Neutron

Answer: (A)

The instrument is designed to respond to photons—gamma rays—rather than the heavier, easily shielded alpha particles or the surface-level beta particles, or even neutrons that require a very different detector material. Gamma radiation is highly penetrating, so detectors used for field surveys will be tuned to register gamma interactions inside a detector volume (like a Geiger-Ma or scintillation crystal) and provide dose-rate readings through shielding and various environments. Alpha particles are stopped by a sheet of paper or the skin, and beta particles need thinner shielding, so they require detectors configured for surface measurements or with very specific window materials. Neutron detection relies on different interactions and materials (such as He-3 or BF3 tubes), which this type of instrument isn’t optimized for. So the Ludlum 2241 is best suited for measuring gamma radiation.