PDR-77 is capable of detecting which types of radiation?

• A. Handheld
• B. Detect alpha, beta, gamma, and x-ray
• C. 3 probes
• D. Survey food, water, personnel, and equipment

Answer: (B)

The main idea is that some survey instruments are designed to detect multiple kinds of radiation by using different detector elements tailored to each type. The PDR-77 is built to sense all four common radiation types—alpha, beta, gamma, and X-ray—in one handheld instrument. This is achieved by combining detectors suited to each interaction: a windowed, thin-shelled detector for alphas so they can be picked up when in contact with surfaces; a beta-sensitive detector (often a plastic scintillator or similar) for beta particles; and a photon detector (like a scintillator or GM-type detector) for gamma and X-ray photons. This multi-detection capability lets the device both identify potential contamination (alpha and beta) and measure dose rate from gamma and X-ray sources. The other options describe the device’s form factor, number of probes, or its surveying scope, not the types of radiation it detects.