A rapid increase in count rate followed by a drop to zero indicates a high radiation field. Perform surveys slowly enough to detect small changes in count rates. Pancake detectors have about twice the counting efficiency for beta emitters than end-window detectors. Scintillation Detectors Scintillation detectors are used for detecting and measuring gamma photons, and are the best detectors for I-125 contamination. Scintillation detectors do not become saturated.
Scintillation detectors are fragile.
They contain glass photomultiplier tubes and brittle, thin crystals. They are significantly more expensive than GM detectors. Plastic scintillators are available for detecting beta particles. Gamma and beta scintillators are made out of different materials and have different operating characteristics. They are useful only in measurement of gamma fields.