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area gamma monitor [ Type : ga 720H]  
Technical Data

Area Gamma monitor (Micro) Type: GA 720H, manufactured & supplied by NUCLEONIX SYSTEMS is designed using state-of-art electronic devices (latest) including microcontroller with embedded code. Use of these devices makes it compact & highly reliable. Powerful embedded code adds-up and enhances its performances and gives extra advantage from the angle of fault diagnostics. This unit is primarily designed to indicate dose rates in the range of (0-100mR/hr).

This unit will be useful for monitoring Gamma dose rate levels in working areas of Radio Isotope Laboratories, Radiology departments, Medical & Industrial Radiological installations apart from its usefulness in Atomic Power Stations and other active labs.

This unit goes into acquisition mode directly after power on after the initial introduction & self check. It indicates dose rate digitally on 6 x 7 segment LED display as well a 16x2 LCD display. There are two visual annunicator lamp windows GREEN & RED for NORMAL & ACTIVE conditions. The ACTIVE window flashes once the dose rate alarm occurs and in normal condition the NORMAL lamp glows.

The user interface is through a front panel keypad comprising of EHT, PROG, INC, DEC, ACK & RESET keys.

PROG key shows up different menu options on successive operation. INC, DEC are used to scroll / select various PROG options. ACK and RESET are used for acknowledging and resetting the unit during Active mode. The unit has user selectable options like Alarm preset level, Baud rate (for serial communication), Reset mode (auto or manual) and other system settings. Pressing EHT key displays the current EHT value in the detector probe.

For external detector arrangement the detector can be connected 10 meters away from the monitor through a cable arrangement.


  • Microcontroller based design has been employed.
  • Dose rate range covered (0.1 - 100) mR/hr.
  • Auto ranging & auto TC selection in the range of 16 sec to 0.5 sec depending upon dose rate.
  • Large size 6 x 7 segment LED indication for dose rate is provided.
  • Designed using GM tube type 130E.
  • Large size WINDOWS for NORMAL & ACTIVE alarm condition q 16x2 LCD display dotmatrix display for visualization & settings of various options.
GA720H with Internal Probe
GA720H with Extermal Probe

Radiation detected : X ray & Gamma Radiation

Range : 0.1 - 100 mR/hr

Detector : Halogen quenched GM tube GM 130E or Equivalent.

Accuracy : +/-10% Full scale

Display : Auto ranging direct reading, 4 digit 7 segment LED display & 16x2 LCD display. 6 x 7 segment display is interfaced using multiplexed display driver IC & used for display of dose-rate information. 16x2 LCD for visualization of preset alarm & other parameters.

Time Constant : Time constant varies continuously from 16 sec to 0.5 sec depending upon countrate

Calibration Accuracy : +/-10% throughout the range

Calibration Stability : Better than +/-10% over a period of six months.

Alarm range : 0.1 - 99.9 mR/hr.
Alarm setting accuracy, calibration stability.
Better than +/-10% over a period of six months.

Alarm System :
a. Alarm indication is by flashing Red (LED) large area window display and Loud audio alarm.
b. Distinctive EHT / Detector failure alarm.
c. The instrument has alarm acknowledgement and Reset switches on front panel.
d. Provision for remote alarm acknowledge and reset.
e. Alarm annunciation scheme: as tabulated below.

Monitor Enclosure : Vapour-tight, rugged & elegant. The instrument can be offered with compliance to required IP standards.

Mounting : Monitor is wall-mountable type.

Data Storage : Microcontroller has on-chip EEPROM to store the preset alarm levels and other Settings.

Self-Diagnostics : The monitor has built-in self-diagnostics. On being powered it performs tests to check for the High voltage supply, Detector and pulse processing electronics .

Power : 91V - 250 VAC +/-10%, 50 Hz, single-phase supply.

Environment : The instrument will be able to withstand temperature upto 60 deg C and relative humidity upto 90% in radiation areas.

Front panel keypad : Keypad provided on Front Panel facilitates user to configure & program the Area Monitor (deactivated by internal jumper selection).

Optional Accessories / Additionaly Features (at extra cost) :
i. Detector probe to measuring unit cable lengths, 5,10,15&20 meters can be provided on request.
ii. (4-20) mA current loop output
iii. Relay contacts through circular I/O connector for external control & use.
iv. RS485 output for networking & data communication
v. Networking software (Net count)
Plot No.162 A & B, Phase-II, IDA, Cherlapally, Hyderabad-500051 India Phone:+91-40-27263701,27262146,040-68888777, Fax : 040 - 27262146
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