How do GM counters calibrate?

Radiological calibration involves exposing the Geiger counter to a radioactive check source and setting the Geiger counter’s measurement of the radioactivity to match the actual known radioactivity of the check source.

Do Geiger counters need calibration?

Geiger counters are required to be calibrated once every year. You can determine when your gieger counter was last calibrated by checking the calibration sticker attached to it. If it has not been calibrated within the last year, you should bring the geiger counter up to Environmental Health and Safety for calibration.

How often should radiation survey meters be calibrated?

annually
Survey instruments should be calibrated at least annually and following servicing. Each individual who will perform calibration on customers’ radiation survey and monitoring instruments should have a set of operating and emergency procedures.

What is efficiency of GM counter?

Counting Efficiency: G-M tubes are nearly 100\% efficient in detecting alpha and beta particles that reach their sensitive volume but only 1-2\% efficient in detecting x- or gamma rays.

What are sources used for instrument checking and calibration radiation?

Sources appropriate for calibration are cesium-137, cobalt-60, or radium-226. If the inverse square law is used with a standard source, the standard source calibration should be traceable to a national standard.

How often must survey meters be calibrated?

As a rule of thumb, a source should be recertified every two to three half-lives or 8 to ten years, whichever comes first. This is particularly important for unsealed plated sources. Calibrations demonstrate that the measurement accuracy is acceptable at the calibration energy (usually 662 keV).

What is the significance of calibration of radiation equipment?

Routine calibration of radiation detection instruments is a required condition of regulatory and radioactive material licensing. All portable count rate meters (commonly referred to as GM Survey meters or “Geiger “ counters) and exposure rate meters (commonly referred to as ion chambers) require annual calibration.