Operating Range

0-.5, 0-5, 0-50 mR/hr 0-500, 0-5,000, 0-50,000 CPM or 0-5, 0-50, 0-500 μSv/hr (SI Scale Meter Option)

Energy Sensitivity

1000 CPM/mR/hr (Cs137). M4EC is the same as M4 except the energy response for gamma and x-rays through the detector sidewall is flat within +61% or -26% over the range of 40 keV to 100 keV, and within +35% or -17% over the range of 100 keV to 1.3 MeV. M4 & M4EC meter scales shown below.
Both Detect beta at 50 keV with typical 35% detection efficiency and beta at 150 keV with typical 75% detection efficiency.