Radalert® 100X


Important: Please select your preferred unit of measurement if you would like it to be set at the factory.  The default displayed units are uSv/hr but the utility menu will allow you to change it to mR/hr anytime on your own.


Radalert® 100X

The Radalert® 100X is a professional radiation survey meter/geiger counter that measures alpha, beta, gamma, and X-radiation.  First responders and industrial workers appreciate the tactile switches, which can be operated with work or safety gloves, and the large and easy-to-read LCD display.   The instrument is designed and built with a passion for quality by a team that has been designing and building radiation detection instruments for 45 years.   The instrument is built to provide personal safety, workplace and environmental safety and to support scientific inquiry.  The Radalert’s Alert Mode allows you to set a threshold level and the instrument will beep when that level is exceeded.   Extremely long battery life using a single and readily available AA battery can give you confidence that your instrument will be ready to go when you need it.
You can use the Radalert to:
  • Monitor personal radiation exposure
  • Detect hazards in the environment, home or workplace
  • Monitor an area or perimeter
  • Detect X Ray leakage
  • Detect radioactive contamination
  • Ensure regulatory compliance
  • Monitor changes in background radiation
  • Demonstrate principles of nuclear physics
  • Detect radioactive minerals in the earth
Features of the Radalert® 100X, include a three-second display update  Its large and easy-to-read liquid crystal display (LCD) shows the current radiation level in your choice of SI units – µSv/h (microsieverts per hour) or conventional units – mR/hr from .000 to 110.  The CPM mode displays CPM (Counts per Minute) from 0 to 350,000.  This instrument also offers an accumulated total and timer function, up to 9,999,000 counts and 40 hours.
 The instrument features a 3-second update on that 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.
The standard Radalert100X instrument ships in the µSv/h mode.  If you would like to receive it operating in the mR/hr mode please advise us and we will make the adjustment for you before we ship.   You can always change the mode later yourself using the Utility Menu.


View Radalert® 100X Specifications

View Radalert® 100X 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% max. (µSv/hr and mR/hr modes)

Alert: User-adjustable alert level to 500 µSv/hr and 60,000 CPM. Beeper sounds the alert

Anti-Saturation: Readout holds at full scale at high radiation levels

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

Calibration: Cesium- 137 (gamma)

Certifications and Compliance: CE, RoHS, no conflict minerals used in manufacturing.

Count Light: Red LED flashes with each count

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

Manual: Radalert®  100X Radiation Detection Instrument

Operating Range:

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

Options: Computer software and cable available


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

Power: One AA alkaline battery (9-volt alkaline battery on older models).  Average battery life can exceed 3,500 hours on AA models  at  normal background radiation levels at sea level. Battery life decreases as radiation level rises.  This instrument (AA versions) can operate with one Energizer Ultimate Lithium Cell for even longer battery life.

Sensitivity: 1000 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


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. 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 International
Medcom, Inc. 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. International Medcom,
Inc. 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.


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