Model 25 Personal Radiation Monitor

Model 25 Personal radiation monitor


The Model 25 and Model 25-1 Personal Radiation Monitors are small, rugged devices designed to warn emergency response personnel of any dangerous fields that they may encounter. These easy-to-use instruments incorporate a GM detector capable of measuring radiation fields up to 9.99 Sv/h (999 R/hr).

The Model 25 Series backlit LCD readout displays dose rate, accumulated dose, and time remaining to the dose limit. Visual and audible alarms can be set over the entire measurement range. No special equipment is required to either calibrate or set up operational parameters.

The units can be worn on a belt, a lanyard, or an armband. A lanyard and a rubber boot with a built-in belt feed through are included with each instrument. See the Options tab below for other available accessories.

Intrinsically safe versions, the Model 25-IS and Model 25-IS-1, are also available for use in areas where explosion safety is a concern.

NOTE: Model 25 Series instruments are not intended to measure background levels of radiation.

Detector Internal energy-compensated GM
Energy Range 60 keV to 2 MeV
Display 3½ digit backlit LCD display
Display Range
Model 25: 0.01 mR/hr (mR) to 999 R/hr (R)
Model 25-1: 0.001 mSv/h (mSv) to 9.99 Sv/h (Sv)
Also displays time remaining from 19:59 to 00:01 (in hh:mm format)
Gamma Response
Model 25: Typically 18 cpm per mR/hr
Model 25-1: Typically 1800 cpm per mSv/h
Alerts & Alarms
Radiation alarms are adjustable over entire range. There are distinct alerts and alarms for exposure and accumulated dose:

Loss of Count Protection If no pulses are received from the detector in 60 minutes, instrument failure is indicated by an audible and visual alarm and the display alternating between "0.0" and "F"
Audio Built-in speaker (typically 95 dB at 30.5 cm [1 ft])
Calibration Requires no tools or software when exposed to a traceable radiation field
Calibrated Range Normally calibrated from:
Model 25: 2 mR/hr to 999 R/hr
Model 25-1: 0.02 mSv/h to 9.99 Sv/h
Temperature Range -40 to 65 °C (-40 to 150 °F)
Power 2 each lithium coin cell batteries
Battery Life Typically 6000 hours. Provides 8 hours warning of low battery.
Construction Injection-molded plastic housing with sub-surface printed membrane front panel, completely gasketed for water resistance
Size (H x W x L) 7.6 x 5.4 x 1.7 cm (3.0 x 2.1 x 0.69 in.)
Weight 144 g (5.1 oz), including batteries