• Radiation Alert® Monitor 200

    Easy to use, great general purpose radiation detector for a wide array of applications. Ruggedized with the included Xtreme Boot. Download your data from the internal memory, set computer alarms, and calibrate with the FREE Observer USB Software.

Monitor 200 / Compact Radiation Detector - a ß y x

Monitor 200

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, and download your collected data from the internal memory for easy reporting!
Monitor 200 Quick Specs


Halogen-quenched GM tube with thin mica end window. Mica window density 1.5-2.0 mg/cm2. Effective window diameter is .360 inch. Side wall is .012 inch thick.

Operating Range

mR/hr - .001 (1µR) to 200 mR/hr
µSv/hr - .01 to 2000
CPM - 0 to 235,400
CPS - 0 to 3923
Total Counts - 1 to 9,999,000 counts


Typically ±15% from factory, ±10% (NIST)

Energy Sensitivity

1070 CPM/mR/hr referenced to Cs137
Detects alpha down to 2.5 MeV; typical detection efficiency at 3.6 MeV is greater than 80%.
Detects beta at 50 keV with typical 35% detection efficiency.
Detects beta at 150 keV with typical 75% detection efficiency.
Detects gamma and x-rays down to 10 keV typical through the window, 40 keV minimum through the case.


Readout will OVERRANGE in radiation fields as high as 100 times the maximum reading.

Selectable Alert Set Range

mR/hr .001 - 100 and CPM 1 - 350,000. Pulsating beeper sounds the alert. Adjustable alert levels are used for mR/hr / CPM, and µSv/hr / CPS. 70db @ 1m. Alarm will sound when in Timer Mode when set alarm threshold is reached.
Energy Response Curve


Graphic LCD with Backlight.

Count Light

Red LED flashes with each count.

Audio Indicator

Sounds with each count (can be switched off for silent operation)


USB for use with Observer USB Software Family

Power Requirements

Two AA alkaline batteries (included). Approx. 800 hrs @ background.

Temperature Range

-10° to 50°C (14° to 122°F)


140 X 68 X 33 mm (5.5 X 2.7 X 1.3 in.)


6.4 oz (0.4 lbs.)


Carrying Case, Xtreme Boot, Lanyard, Stand, Batteries, Mini-USB Cable, Observer USB Software Download, Certificate of Conformance


NIST Calibration

Limited Warranty

1 year limited warranty


Operation Manuals | English | Spanish | Monitor 200 Quick Specs | Frequently Asked Questions
Monitor 200
The Ranger
The Ranger EXP
Monitor 1000EC
a ß y x y x
Internal Memory
Included Protective Boot
Included Stand
Built-In Isotope Efficiences    
GM Detector Internal Internal External (EXP) Internal
mR/hr .001(1µR) to 200 .001(1µR) to 100 .001 (1µR) to 1000 mR/hr
µSv/hr - .01 to 2000 .01 to 1000 .01 to 10000
mSv/hr n/a n/a 0.00001 to 1
Counts Per Minute 0 to 214,000 0 to 350,000 0 to 450,000
Counts per Second 0 to 3575 0 to 5000 0 to 7500
Total Timed Counts 1 to 9,999,000

Accessories / For The Monitor 200 Radiation Detector, Survey Meter, and Geiger Counter

Monitor 200

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