Radiation to be detected :
X – ray & Gamma Radiation

Range :
0.01 mR/hr to 99.99 mR/hr (0.1 µSv/hr to 999.9 µSv/hr)
0.1 mR/hr to 19.99 R/hr (1µSv/hr to 199.99 mSv/hr)
0.1 mR/hr to 1000.0 R/hr (1µSv/hr to 10000 mSv/hr)

Detector : Four nos. of GM probes using energy compensated halogen quenched G.M. Tube/s. Detector will be extendable upto 50 mtrs. Instrument can be offerred with any of the following probes and connectivity for a maximum of 4 probes is supported
Detector probe 1 : Uses GM131E or equivalent
Detector probe 2 : Uses GM131E or equivalent
Detector probe 3 : Uses GM131E or equivalent and LND7149 or equivalent
Detector probe 4 : Uses GM131E or equivalent and LND7165 or equivalent

Energy dependence : Within +/- 20% of true dose rate from 100 keV to 1.33 MeV gamma rays.

Accuracy : +/- 10% with Cs-137

EHT : 400V to 700V DC adjustable (Typical 500V)

Display : 7.5” colour LCD or better is used for display of dose-rate and hardware status indication & also for parameter entry

Overload : Senses overload dose-rate & indicates on display “OL”

Over-range : Senses if the radiation field being measured has exceeded the counting range of the instrument and displays “OFL”

Recorder output : 4 nos. of current outputs for each of the detector channels, 4 to 20 mA, with 600 ohm load. Generates 22.5mA in the event of hardware failure or overflow or overload condition

Recorder output stability : + 0.2%

Time constant : First reading on power ON within 5 secs.
Normal (Slow) : 30 secs. to 0.5 automatically varying inversely with the radiation level (count rate) for probes 1,3,4.
Normal (Fast) : 15 secs. to 0.5 automatically varying inversely with the radiation level for probes 2.
Abrupt detection : Update the current reading within 2 secs. and return to normal mode.

Calibration accuracy : +/- 10% through out the range.

Instrument “ON” indication : Large area green LED lamp. This will indicate the normal condition also.

Alarm range : The alarm level setting will be settable throughout the range of the instrument. The alarm level setting can be carried out through Ethernet port from PC or from front panel keypad with password protection.

Alarm indication :
a)Red (LED) flashing large area window display.
b)Loud audio tone (frequency selectable)

Alarm annunciation scheme :
As tabulated below

Instrument controls :
• Acknowledgment switch for muting audio
• Reset switch for resetting the alarm indication and alarm relay of corresponding channels which are below preset levels
• Power ON/OFF switch (This is inside the cabinet) with power ON indication

Instrument fault indication :
• EHT failure : Visual alarm with flashing red LED indication & “Eht” message on display for corresponding probe channel.
• Detector failure : Visual alarm with flashing red LED & “d-FL” message on display on display for corresponding probe channel.
• Microprocessor / microcontroller failure : Visual alarm with flashing green lamp.
• Fault indications shall be cleared automatically if normal status is resumed.

Detector housing :
• The G.M detector probes are located external to the monitor.
• They will be housed in a suitable, air-tight SS shell with built-in pre-amplifier to drive upto 50 mtrs long cable.
• The instrument is provided with 10 mtrs cables between detectors and the monitor.
• The detector housing will qualify minimum industrial protection class IP-54.
• Provision to connect the detector with short cable also shall be available.
• A separate bracket for wall mounting of the detector housings will be provided.
• Centre of the detectors are marked on the housing.

Monitor enclosure :
• Vapour-tight, rugged & elegant.
• The door is provided with lock and key arrangement the enclosure shall qualify minimum industrial protection class IP-54.
• Decorative with visual aesthetics, prominent alarm display and good readability.
• The monitor will be provided with identical MS connectors for the 4 detector probe channels.
Mounting : The monitor is wall mountable type. Brackets for the monitor & detector housing shall be supplied along with the equipment.

Remote / external console :
• Four nos. of 4 – 20 mA linear proportional to full scale output. Current output will be able to drive load of 600 ohms. Output circuitry shall be able to drive 200 mtrs. of twisted pair of wires.
• Four sets of potential free contacts of alarm relay (change over). Contact rating 3 amp at 250V AC. The relay shall be energized on normal condition and de-energised under alarm condition.
• Remote alarm acknowledgement and reset signals for the field instruments (Normally open contact).
• Indication of instrument fault condition (detector, EHT, counts failure & over-range / overload conditions) by up-scale 4-20 mA. (22.5mA).
• All these signals shall be terminated on a suitable MS connector of allied or equivalent make. The corresponding mating plug wit 5 mtr cable shall be supplied with the monitor.

Computer interface : The monitor shall have a Ethernet 10/100 Mbps port for interfacing with a remote IBM PC-compatible computer. The features supported by Ethernet port are given below.
• The PC and the monitor shall operate in a host-slave configuration and the software protocol will be MODBUS/TCP.
• The PC as the host shall give commands and send queries. The monitor will carry out various functions in response to the queries.
• The firmware of the monitor shall be able to send the instrument data like instrument ID, instrument type, input range, display range, alarm settings, alarm status, current reading, diagnostic status of EHT/GM tube etc. to the Host PC on demand.
• The firmware shall be able to receive commands from Host PC and carry out the setting of different parameters like instrument ID, instrument type, input range, display range, alarm settings, Ack, Reset, EHT setting, instrument address etc.

Data storage of radiation history : 128MB of flash has been provided for storage of doserate history from individual probes with time stamp this can be dumped to the PC on command.

Front panel keypad : The monitor will be provided with a front panel keypad for programming the instrument. The keypad along with the LCD display shall enable the user to configure the instrument for all functions and will be password protected (user defined)

Self diagnostics : The monitor shall have built-in self diagnostics. On being powered it shall performs tests to ensure that all components and sub systems are functioning properly. It shall check for the power supply, High voltage supply, detector and pulse processing electronics.

Input power : 230V AC +/- 10% 50Hz, single phase supply. Power ON/OFF switch shall be proved with a neon indicator. Spike suppressor and line filter are also provided.

Environment : The instrument shall be able to withstand temperature upto 50 deg C and relative humidity upto 90% in radiation areas.

The instrument enclosure and detector assembly will comply with IP-54. Electronic units will withstand cumulative radiation dose of 10000 Rad. (30 years of operation).