Monitor 4 & 4EC Handheld Radiation Alert® Detector
Same Monitor 4. New ergonomic design. The M4 and M4EC are compact, general purpose survey meters capable of detecting alpha, beta, gamma, and x-rays over 3 selectable ranges. A red count light flashes and a beep sounds with each event detected. The Monitor 4EC offers a more linear reading for gamma and x-rays (above 40 keV).
Monitor 4: Halogen-quenched uncompensated GM tube with thin mica window 1.5-2.0 mg/cm2 thick.
Monitor 4EC: Halogen-quenched GM tube, energy compensated sidewall 2mm tin filter. Thin mica window 1.5-2.0 mg/cm2 thick.
Analog Meter holds full scale in fields as high as 100X maximum reading.
Monitor 4 Energy Sensitivity
M4: Detects alpha down to 2.5 MeV; typical detection efficiency at 3.6 MeV> 80%. Detects beta at 50 keV with 35% efficiency. Detects beta at 150 keV with 75% efficiency. Detects gamma and x-rays down to 10 keV through the window, 40 keV minimum through the sidewall. Normal background is approximately 10-20 CPM.
M4EC: is the Same as Monitor 4 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.
1000 CPM/mR/hr (referenced to Cs-137)
Energy Sensitivity for the 4EC is the Same as Monitor 4 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.
0-.5, 0-5, 0-50 mR/hr
0-500, 0-5,000, 0-50,000 CPM or 0-500 µSv/hr
X1, X10, X100, Battery Check.
Typically ±15% of reading (referenced to Cs-137)
Internally mounted beeper (can be turned
off for silent operation).
9-volt alkaline battery up to 2,000 hrs at
-20° C to 55° C (-4° F to 131° F).
M4: 223.9 grams (7.9 oz) without battery
M4EC: 245.7 grams (8.7 oz) without battery
3.5 mm headphone jack with pulse out.
210 x 70 x 48 mm (8.25 x 2.75 x 1.875 in.)
Carrying Case, Observer Software, USB Option, SI Meter Option
1 year limited warranty
The Ranger offers maximum performance in a lightweight, rugged solution for surveying at the facility or in the field. The Ranger has been designed for industrial environments, but it still has all of the features you've come to love in the lab. The Ranger is a small, handheld, microprocessor-based instrument which offers excellent sensitivity to low levels of alpha, beta, gamma, and x-rays and has built in efficiencies for common isotopes to calculate activity in Bq and DPM. It has a backlit digital display, a red count light, and a beeper that sounds with each count detected. Other features include selectable alert levels, an adjustable timer, and an optional wipe test plate for swipes. Internal memory and the free Observer USB Software that allows you to download your data, set computer alarms, and calibrate your instrument!
The Monitor 200 measures alpha, beta, gamma, and x-rays. Its digital display shows readings in your choice of CPM, CPS, μSv/ hr, mR/hr, or in accumulated counts. It has a digital display, a red count light, and a beeper that sounds with each count detected. Other features include an adjustable timer, and selectable alert. With the free Observer USB Software Family, you can set computer alarms, calibrate your instrument, and download your collected data from the internal memory for easy reporting!
The Ranger EXP offers maximum performance in a lightweight, rugged solution for using your survey meter in the field. The Ranger EXP is designed specifically for individuals operating in tough environments. The small, handheld unit offers excellent sensitivity to low levels of alpha, beta, gamma, and x-rays. The digital readout is displayed with a red count light and a beeper sounds with each count detected. Other features include an adjustable timer, selectable alert, and with the free Observer USB Software Family, you can download your collected data, set alarms, and calibrate your meter!
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RDS-31 Multi-purpose Survey Meter is a small hand held, battery operated survey instrument using an energy compensated GM-tube as primary detector. Due to its versatile functions and durability it is suited for a wide range of applications e.g. in civil defense, industrial and laboratory use.