Counts per second (CPS) is the raw output rate of a radiation detector, such as a Geiger-Muller tube or scintillation counter. It represents the number of ionizing events the instrument registers each second, before any conversion to dose rates or activity. Technicians use CPS to quickly assess the relative intensity of a radiation field or to locate contamination hot spots during a survey.
The pancake probe is reading about 400 CPS on the bottom of this boot, so we definitely have some removable contamination.
A high CPS reading means high activity, but you cannot convert CPS directly to dose without knowing the specific isotope, the detector's efficiency, and the geometry of the source.
Also heard as
- c/s
Do not mix it up with
- Becquerel: Becquerel measures the actual number of disintegrations per second in the source, while CPS only measures the fraction of those disintegrations that hit and trigger the detector.
Related terms
Survey meter
A portable instrument used to measure radiation dose rates or detect contamination in the field.
Pancake probe
A flat, wide-window Geiger-Mueller detector used for frisking because it picks up beta and alpha contamination well.
Frisker
The count-rate meter and probe kept at exits for checking hands, feet and clothing for contamination.
Background
The ever-present radiation from natural and other sources that an instrument reads when no source of interest is near.