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Environment, Health and Safety

Choosing A Survey Meter

When choosing a portable survey instrument, the type of detector (or probe) must be chosen according to the kind of radioactive material that is being used.

Survey Meters

Generally, thin window Geiger-Mueller (GM) probes are best suited to detect beta radiation with energies above 70 keV while sodium iodide (NaI) scintillators are best for gamma radiation. 

For campus laboratories, EH&S recommends the Ludlum Model 3 survey instrument. The Model 3 has the following detectors available:

Geiger Counter

Ludlum Model 3 with Pancake Probe

For Beta Radiation

If you are using P-32, Ca-45, Cl-36, C-14 or S-35 use the Ludlum Model 3 Survey Meter with Model 44-9 "Pancake" GM Probe. This instrument has a flat detector (1.75" in diameter) at the end of a handle. This style probe is comfortable to handle and is best suited for surveying large areas, such as floors, hoods and bench tops.

Geiger Counter with Low Energy Gamma Scintillator Probe

Ludlum Model 3 with HEG Probe

For Gamma Radiation

If you are using I-125 or other nuclides with gamma energies between 10 to 40 keV, use the Ludlum Model 3 survey meter with Model 44-3 "Low Energy Gamma" Sodium Iodide (NaI) detector.

If your are using Cr-51, I-131, Co-57 or other nuclides with gamma energies above 40 keV, use the Ludlum Model 3 survey meter with Model 44-2 "High Energy Gamma" NaI detector.

Ordering Information

When ordering the Model 3, you must specify the 0 - 5000 cpm meter face and a MHV detector connector (type UG-932/U). This will make your instrument compatible with similar instruments on campus and easier for us to calibrate.

The address of the area sales representative is:

John Anderson, Jr.

Atlantic Nuclear

1020 Turnpike St. #9

Canton, Massachusetts 02021

Telephone: (800) 878-9118; (781) 828-9118

FAX: (781) 828-1319


Please let us know when your instrument arrives so that it can be added to our calibration schedule.