Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200
Monitor 200

Monitor 200

The Monitor 200, your go-to solution for precise and versatile radiation detection. This state-of -the-art device measures alpha, beta, gamma, and x-rays providing accurate readings displayed in your preferred unit of measurement. Choose from CPM, CPS, μSv/hr, mR/hr, or in accumulated counts.

Featuring a digital backlit display, the Monitor 200 ensures easy readability in any environment. The addition of a red count light and an audible beeper accompanying each count detected enhances your awareness during radiation monitoring. With an adjustable timer and customizable loud alert, this radiation detector is tailored to meet you specific needs, offering both accuracy and user-friendly functionality.

Free Observer USB Software
Free Observer BLE Software For Use With The
Optional Bluetooth Module

The Monitor 200 doesn't just stop at on-the-spot readings- it's equipped with internal memory and Included with your purchase is the Free Observer USB Software(compatible with Windows only), enabling you to effortlessly download and manage your data while setting up computer alarms for added convenience.

For an enhanced experience, the optional Bluetooth module opens up a world of possibilities.  The Radiation Alert® Monitor 200 seamlessly integrates with the free Radiation Alert® Observer BLE app available for download from the Google App Store.  This app empowers you to display real-time readings with descriptions, conduct timed counts, append GPS data, and send your saved survey files. What's more, any alarms set on the instrument will be mirrored on you android device, ensuring you stay informed and in control.

 Applications & Uses: Checking accelerator & x-ray shielding for leakage, industrial gauges containing Cesium-137, Locating Sources, Personal protection, General surveying

Helpful Videos
Monitor 200 Taking a Timed Count    Monitor 200 Setting The Alarm  
Monitor 200 Backlight                         
Monitor 200 Silent Operation

Digital Radiation Detector Comparison | Contact For Pricing and Availability



radiation_icon_bllack alpha_icon_black beta_icon_black gamma_icon_black x-ray_icon_black

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

 Monitor 200 Detector Window

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.
(Ref to Cs137)Monitor 200 & Monitor 4 Energy Response To Gamma Cs137

Accuracy of Radiation Detector Device

Referenced to Cs137
Typically ±15% from factory, ±10% with NIST Source Calibration NIST Calibration Additional


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

Included with Monitor 200
Option Carry Case                 Stand  
Carrying Case Stand  
Observer BLE  Observer Software  
Observer BLE Software for Android Observer USB Software  
Extreme Boot    
Extreme Boot    

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.


Graphic LCD with Backlight.


USB for use with Free Observer USB Software for PCs
Bluetooth Option Additoinal: Wirelessly connects the instrument with an Android mobile device for use with Free Observer BLE App

Count Light

Red LED flashes with each count.

Audio Indicator

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

Power Requirements

USB Power or Two (2) AA alkaline batteries (included). Approx. 800 hrs @ background.

Temperature Range

-10° to +50°C (14° to 122°F)


10% to 70% Non-Condensing.


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


181 g (0.4 lbs.)


Carrying CaseXtreme Boot, Lanyard, Stand, Batteries, Mini-USB Cable, Observer USB Software Download, Observer BLE App Certificate of Conformance
Bluetooth module available for use with Observer BLE APP and Rad Responder


Water Resistant Case , NIST Calibration

Limited Warranty

1 year limited warranty


Options for Monitor 200

Water Resistant case  Rad response kit        
Water Resistant Case Radiation Response Kit