Rad 100™


Important: Please select your preferred unit of gamma radiation  measurement.  Options are mR/hr or uSv/hr.  Instrument will ship with the setting you prefer.  The default setting is uSv/hr.  You can change it anytime using the utility menu (see operation manual).


Rad 100™

The RAD 100™ is a professional general purpose radiation survey meter/geiger counter that detects and measures alpha, beta, gamma, and X-radiation. It is intended for personal safety, workplace and environmental safety and scientific purposes.  First Responders and industrial workers appreciate the tactile switches, which can be operated with work or safety gloves.  Like the popular Radalert® 100X, the RAD 100™ features a 3-second update on its large and easily readable liquid crystal display (LCD). The LCD displays the current radiation level in your choice of µSv/h (microSieverts per hour) (SI units) or mR/hr – for gamma radiation measurements.  For mixed sources (alpha, beta, gamma) the CPM mode is recommended.  This instrument also offers an accumulated total and timer function, up to 9,999,000 counts and 40 hours for analysis of samples and detection of subtle radiation level changes. A red LED blinks and a beeper chirps with each count (the chirp can be muted).  This is a professional instrument that is also easy to learn to use and to operate, and carries the industry leading Medcom warranty (2 years overall limited to 1 year on the GM sensor).  Many instruments designed by the Medcom team are still working perfectly after 35 years of use, so with proper care this instrument should provide a lifetime of useful service.  For rugged workplace environments the optional multi purpose Protect® Boot provides an extra level of protection, a magnetic belt clip, and a tilt stand.


View Rad 100 Specifications

View Rad 100 Manual





  • Halogen-quenched Geiger-Mueller detector (LND712)
  • Mica end window density is 1.5-2.0 mg/cm²
  • Side wall is 0.012″ #446 stainless steel
  • Detects Alpha, Beta, Gamma, and X-radiation

Display: 4-digit liquid crystal display with mode indicators

Accuracy: ±10% typical; ±15% maximum

Alert: No Alert feature. If your intended application requires a user-adjustable Alert, we recommend the Radalert® 100X

Audio: Beeper chirps for each count (can be muted)

Calibration: Cesium 137 (gamma)

Certifications: CE Certified, RoHS Compliant, and Meets WEEE standards

Count Light: Red LED flashes with each count

Designed & Manufactured: Designed and Manufactured in USA by IMI International Medcom, Inc.

Operating Range:

µSv/hr: .000-1,100 CPM: 0-350,000
mR/hr: .000-110 CPS: 0-3,500
Total: 0-9,999,000 counts Timer: up to 40 hours

Options: Computer software and cable available

Operation Manual: Rad 100 Manual


    • Output: Stereo 3.5 mm jack sends counts to computers, data loggers, other CMOS-compatible devices, and headphones, and educational data collection systems.0-9 V, 1 kOhm impedance.
    • Input: Mono 2.5 mm jack provides calibration input. 0-3.3 V, >5 μs width, rising edge triggered.

Power: One AA alkaline battery (one 9-volt alkaline battery on some models); average battery life typically exceeds 3600 hours at normal background radiation levels at sea level. Battery life decreases as radiation level rises.

Gamma Sensitivity: 1,000 CPM/mR/hr referenced to Cs-137

Size: 150 x 80 x 30 mm (5.9″ x 3.2″ x 1.2″)

Weight: 225 grams (8 oz) including battery

Specifications subject to change without notice.


International Medcom is passionate about quality and customer satisfaction. We provide the best radiation detector warranty available anywhere.

This product is warranted to the original owner to be free from defects in materials and workmanship for two years from the date of purchase with the exception of the Geiger-Mueller tube, which is warranted for one year. The battery is not included in this warranty. IMI-International Medcom, Inc. will, at its own discretion, repair or replace this instrument if it fails to operate properly within this warranty period provided that it has not been subjected to misuse, abuse, or neglect. Modification or repair of this instrument by anyone other than IMI voids this warranty.

Contamination of this instrument with radioactive materials voids this warranty. Contaminated instruments will not be accepted for servicing at our repair facility.

The user is responsible for determining the suitability of this product for the intended application. The user assumes all risk and liability connected with such use. IMI is not responsible for incidental or consequential damages arising from the use of this instrument.

The terms of this warranty are subject to change without notice.


Optional Accessories

Protect® Silicone Boot

GeigerLink computer interface USB adapter (works with Medcom Apps)

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