Which Survey Meter Do I Need?

Types of survey meters:

• Contamination
• Dose rate
• Ion chambers
• Alpha/beta detectors

How to Use a Survey Meter

A survey meter is probably your most useful tool in assessing contamination in the laboratory when you are working with radioactive materials. It can be used to identify areas of contamination in the work area and to survey areas where you don't suspect contamination. It should also be used to check yourself to ensure that you have not contaminated your lab clothing, personal clothing and, most importantly, your skin.

Tritium (H-3) is not detectable with a standard GM meter. You must rely on swipe data for meaningful information. Listed below are some helpful reminders on how to check your meter prior to surveys and how you should operate your meter.

PRE-OPERATIONAL CHECKS

• Make sure your meter has been calibrated within the past year.
• Use your battery check switch to ensure that there is enough battery power to operate your meter.
• Use a check source to ensure that your meter responds to a radiation field. If no check source is available, you can check the meter against a known radiation source. 

Note: If your meter fails any of the above tests, it is not valid for meter surveys. You can request a loaner meter from EHS while yours is being calibrated or fixed. To have your meter calibrated, see the How to Maintain Instrument Calibrations section on this page.

OPERATION

When surveying for contamination using a GM (or appropriate detector), use a slow sweeping motion (5-8 cm per second) approximately 1 cm away from the surface being surveyed. Be careful to avoid sharp objects when surveying. The probe window is fragile and could puncture (about $100 to replace). 

Remember to use the survey meter to check for areas where you also may want to swipe. Just because you can't see contamination on the meter does not mean that it is not there. Conversely, you may find contamination with the meter and not a swipe because it may be "fixed" and not readily removable.

How to Troubleshoot a Survey Meter

LOW BATTERY OR BATTERY INDICATOR OUT OF RANGE

Replace batteries on detector. Make sure detector is off before removing the old batteries and replacing with new ones.

Make sure polarity is correct. This is an easier mistake to make on Ludlum Model 3's.

Calibration and Maintenance

Detectors should be sent off annually for calibration by a qualified company. EHS no longer provides in-house calibrations. Commonly used companies for calibrations include Ludlum and Mirion. 

If you're detector is broken, it will need to be sent to the manufacturer for repair or replacement. If you attempt in-house repair of a detector, verify that detector is still correctly reading a dose signal after repair. If it is not, detector will need to be sent off for calibration.