Area monitor for pulse radiation

Flexible and reliable monitor, designed for control of impulse radiation during operation of linear electron accelerators or other pulse action installations.
The system consists of АТ1123 X-ray and gamma radiation dosimeters and components of АТ2327 Alarm dosimeter.

Operating principle
The monitor is structurally divided into measuring channels (1 – 32) connected to switchboard unit. Each channel comprises a measuring component (АТ1123 Dosimeter) and a connecting component (АТ941 Interface adapter and АТ960 Surge protector) fixed to a wall in close proximity to each other.
Any of the channels can be equipped with AT991u light and sound alarm unit with potential-free contacts allowing to connect various actuators, such as lock devices, etc.
Radiation level data from each channel are transmitted over cable into switchboard unit and then to a PC-based operator panel. Individual control channel can be mounted inside control room for safety reasons.
The monitor operation is controlled by a dedicated "SARK2 PXR" software allowing reading and analysing measurement data as well as setting and changing configuration. Operator panel displays monitored site plan with measurement result values at control points presented in the form of graphs and tables.
If one of measuring channels or communication lines fails, the rest continue operation in stand-alone mode preserving all alarm, measurement and data storage functions.
▪ Plastic tissue-equivalent detector
▪ Measurement of pulsed radiation from 10 ns
▪ Independent measurement for each channel in wide range of dose rates and energies
▪ Sound and light alarm for each measurement channel in case threshold levels are exceeded
▪ Fault diagnostics
▪ History logging of dose rate levels and cases of threshold crossing
▪ Software for displaying current radiation environment in monitored site on PC screen
▪ Backup power supply unit
▪ The monitor can be used for dosimetric control of continuous gamma radiation
▪ AT1123 dosimeter can be operated in off-line mode as a portable instrument



Scintillation plastic, Ø30x15 mm

Measurement range of ambient gamma and X-ray radiation dose equivalent rate



- For pulsed radiation

0.1 µSv/h – 10 Sv/h

- For continuous radiation

50 nSv/h – 10 Sv/h

Measurement range of ambient gamma and X-ray radiation dose equivalent


10 nSv – 10 Sv

Energy range


- For pulsed radiation

15 keV – 10 MeV

- For continuous radiation

15 keV ... 10 MeV

Energy dependence relative to 662 keV (137Cs)


15 ... 60 keV (with protection cap "0.025 – 3 MeV")


60 keV ... 3 MeV (with protection cap "0.025 – 3 MeV")


60 keV ... 10 MeV (with protection cap "0.06 – 10 MeV")


10 ... 20 MeV * (with protection cap "0.06 – 10 MeV")

±50% max

Minimum duration of pulsed radiation for impulse dose rate up to 1.3 Sv/sec


10 ns

Limit of intrinsic relative measurement error


- For pulsed radiation


- For continuous radiation


Sensitivity to 137Cs gamma radiation

70 cps/µSv·h-1

Time of 137Cs gamma radiation dose rate measurement with statistical error ±15% (P=0.95) for the following dose rate:


50 nSv/h

≤60 s

0.3 µSv/h

≤10 s

over 2 µSv/h (Up to 10 Sv/h)

≤2 s

Response time for dose rate change from 0.1 to 1 µSv/h

<2 s (accuracy error ≤±10%)

Burn-up life

≥100 Sv


3-stage light alarm and sound alarm

Maximum distance from AT1123 dosimeter to operator panel

1000 m

Initialisation time

≤5 min

Power supply

a) 230 VAC (+23/-35) V, 50±2 Hz

b) Rechargeable battery for emergency power supply

Continuous run time

a) ≥24 h with AC mains power supply

b) ≥6 h with self-contained supply from fully charged battery



- AT1123 Dosimeter

RS 232

- АТ991u Alarm Unit

RS 485

Operation temperature range

From -30оС to +50оС

Relative air humidity with temperature 35оС and below without moisture condensation



Protection rating


- AT1123 Dosimeter


- АТ941 Interface adapter


-АТ960 Surge protector


- АТ991u Alarm Unit


- When АТ1123, АТ941, АТ960 are located inside cabinet


Overall dimensions, weight


- AT1123 Dosimeter

233x85x67 mm, 0.9 kg

- АТ941 Interface adapter

206х82х56 mm, 0.4 kg

- АТ960 Surge protector

206х82х56 mm, 0.4 kg

- АТ991u Alarm Unit

185x85x95 mm, 0.4 kg

*Energy dependence in 10 ... 20 MeV range is based on Monte Carlo method and is for reference only

Design and specifications are subject to change


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