Area Monitors

 Area Monitoring System

 Model 375 Series


Model 375 Controller

The Model 375 is a versatile, compact and very affordable digital electronic controller designed for monitoring radiation in areas. Its simple design accommodates many different detectors suiting a wide variety of applications and is equipped with a local readout and alarms.

These versatile units may also be connected to an optional remote indicator/annunciator for alerting personnel at other locations. The user-friendly, digital design enhances setup and operation. These units may also be networked to a central PC-based station where data are logged and alarms posted.

Learn more about the Model 375 Controller...



Model 375-Dual Controller

Ludlum also supplies a Model 375-Dual that combines two controllers into one package.  Learn more...


















Detector Range

Detector Type

Model Number

1.0 µSv/h-10 mSv/h
(0.1 mR/hr-1.0 R/hr)
Energy compensated GM (internally mounted) 375/2
10 µSv.h-100 mSv/h
(1.0 mR/hr-10 R/hr)
Energy compensated GM (internally mounted) 375/4
Any 4 consecutive
decades between
 0.1 mR/hr-100 R/hr
Ion Chamber (external detector) 375-9
0.1 - 20 µSv/h 
(1 - 2000 μR/hr)
5.1 x 5.1 cm (2.0 x 2.0 in.) NaI Scintillator
with removable shield (internally mounted)
0.1 - 9999 µR/hr 18 mm CsI detector mounted inside M375 housing
(internally mounted)













Ethernet Connectivity


Webpage & Service Software

Model 375s equipped with the ethernet option can be connected to a radiation network that collects and displays radiation levels and alarm status in real time from up to 50 area monitors.  A standard webpage browser with appropriate authorization can view all data across the network and audibly annunciate any alarms.  The system can also be setup to send intelligent email alerts to responsible personnel and capture a picture of whatever triggered an alarm anywhere optional ethernet cameras are employed.

Learn more...









Optional Remote Indicators


Model 271
Model 271-2


 Model 272


Model 272D


Frisker / Area Monitor

Model 3276


Simple Setup and Use
Versatile Instrument: Can be Used as Wall Monitor or Frisker
User-Adjustable Alarms
User-Programmable Units of Measurement, Can be Either English or SI Units
Uses Either Internal or External Detector for Alpha, Beta, or Gamma Radiation
Standard Alkaline (4) “AA” Battery Power or 9 Vdc Wall Mount Transformer
Learn more...