Radiation Detectors / Geiger Counters & Survey Meters


The Digilert 200 measures alpha, beta, gamma, and x-rays. Its digital display shows readings in your choice of counts per minute (CPM), CPS, µSv/hr, mR/hr, or in accumulated counts. Now with USB and the included Observer USB Software, you can download your accumulated data from the Digilert200’s internal memory, set alarms, and calibrate your instrument!


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 214,000
CPS - 0 to 3575
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.


Pulsating beeper sounds the alert. Adjustable alert levels are used for mR/hr / CPM, and µSv/hr / CPS. Alarm will sound when in Timer Mode when set alarm threshold is reached.
Energy Response Curve


Backlit 4-digit liquid crystal display with mode indicators. Display updates every 3 seconds.

Count Light

Red LED flashes with each count.

Audio Indicator

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


3.5mm jack for CMOS or TTL devices and counts to computer or datalogger. USB for use with Observer USB Software for PCs

Digilert 200 in Xtreme BootPower Requirements

One 9-volt alkaline battery. Battery life is approx. 1200 hours at normal background radiation levels.

Temperature Range

-10° to +50°C (14° to 122°F)


217 g (7.7 oz.)


150 x 80 x 31 mm (6.1 x 3.1 x 1.2 in.)


Carrying Case, Observer USB Software Download, USB Cable, Certification of Conformance.


Xtreme Boot & Stand

Limited Warranty

1 year limited warranty