A handheld instrument carried by RP technicians. Ion chamber meters measure gamma and beta dose rates accurately over a wide range; Geiger-Mueller meters with probes are more sensitive and used to find contamination and low fields; neutron meters, often a ball-shaped moderator around a detector, measure neutron dose rate. Each meter is calibrated, source-checked daily and chosen to suit the radiation type and range expected.
Take the ion chamber survey meter for the dose rates and the frisker with a pancake for the floor.
Use an ion chamber to measure fields and a GM to hunt contamination; a GM tube in a strong field can saturate and read misleadingly low.
Also heard as
- survey instrument
Related terms
Cutie pie
Nickname for a handheld ion chamber survey meter, taken from a classic pistol-grip design.
Pancake probe
A flat, wide-window Geiger-Mueller detector used for frisking because it picks up beta and alpha contamination well.
Background
The ever-present radiation from natural and other sources that an instrument reads when no source of interest is near.
Roentgen
A unit of exposure that measures how much X or gamma radiation ionises air.