A Geiger-Mueller tube shaped like a shallow disc with a thin mica window of roughly 15 square centimetres, covered by a protective screen. The thin window lets beta and much alpha radiation in, making it the standard probe for frisking skin, clothing and small items. Touching a surface with it risks puncturing the window or contaminating the probe, so users hold it just off the surface and cover it with thin plastic in dirty areas.
Cover the pancake probe with a glove finger before you frisk that valve, I don't want to contaminate the window.
Also heard as
- pancake
- GM pancake
Related terms
Frisker
The count-rate meter and probe kept at exits for checking hands, feet and clothing for contamination.
Frisking
Slowly scanning a person or object with a contamination probe to find radioactive material before it leaves an area.
Survey meter
A portable instrument used to measure radiation dose rates or detect contamination in the field.
Smear
A wipe of a surface with filter paper, counted to measure how much removable contamination is present.