AT1121, AT1123 X-RAY and Gamma Radiation Dosimeters

Photon radiation energy range 15 keV ... 10 MeV
Portable multifunctional wide-range instruments for X-ray and gamma radiation dosimetry of the following types:
▪ Continuous long-term radiation
▪ Continuous short-term radiation
▪ Impulse radiation [AT1123]
▪ X-ray diagnostics
▪ Nuclear medicine
▪ Radiology
▪ X-ray and gamma-ray flaw detection
▪ X-ray and gamma-ray testing
▪ Search X-ray and accelerating apparatus
▪ Radiation accidents
▪ Radiation monitoring
▪ Nuclear industry
▪ Accelerating installations
▪ Research activities

▪ Tissue-equivalent detector - scintillation plastic
▪ High sensitivity results in rapid measurements with good statistical confidence
▪ Wide measurement range with 8 orders of magnitude and more
▪ Wide energy range starting from 15 keV
▪ Measurement of short-term exposure dose rate and time (from 0.03 s) for continuous radiation
▪ Measurement of average dose rate of impulse radiation with duration from 10 ns [AT1123]
▪ Large dedicated digital/analogue LCD screen with backlighting
▪ Integrated system for LED measurement path stabilization
▪ Sound and visual alarm in case threshold level is exceeded
▪ External control panel can be used for remote measurement
▪ Fixed installation option with external audio-visual alarm with four groups of potential-free contacts for actuator control
▪ Connection to PC is available in order to create a continuous monitoring system with documenting function
▪ Tree types of power sources
▪ Severe operating conditions

Operating principle
Main function of the dosimeter is the measurement of X-ray and gamma radiation within wide ranges of ambient dose equivalent rate and energy. Additional functions: detecting soft and hard gamma radiation sources, beta radiation sources, short-term and pulsed radiation with exposure time assessment, and detecting moving sources as well.
Dosimeters automatically save maximum dose rate value for the time of operation and are able to store up to 999 measurement results in non-volatile memory for a long time and to subsequently transfer this data to PC.
Continuous performance self-testing is done during operation.
External control unit and external alarm unit can be attached to dosimeters for remote monitoring application.

Dosimeter with external control and external alarm units




Scintillation plastic, Ø30x15 mm

Ambient dose equivalent rate measurement range


- Continuous long-term radiation


     AT1121, AТ1123

50 nSv/h ... 10 Sv/h

- Continuous short-term radiation


     AT1121, AТ1123

5 µSv/h ... 10 Sv/h

- Impulse radiation



0.1 µSv/h ... 10 Sv/h

Ambient dose equivalent measurement range

10 nSv ... 10 Sv

Energy range


- Continuous long-term and short-term radiation

15 keV ... 10 MeV

- Impulse radiation (АТ1123)

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") ±25%

     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 impulse radiation for impulse dose rate 1.3 Sv/s (AT1123)

10 ns

Minimum duration of continuous short-term radiation

0.03 s

Intrinsic relative measurement error


- Continuous long-term and short-term radiation

±15% max.

- Impulse radiation

±30% max.

Sensitivity to 137Cs gamma radiation

70 cps/µSv·h-1

Response time for dose rate change from 0.1 µSv/h to 1 µSv/h (accuracy error ≤±10%)

<2 s

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

Sensitivity to associated beta radiation of 90Sr + 90Y with filter (with protection cap "0.06 – 10 MeV") at 5 cm distance

3·10-7 µSv·h-1·Bq-1

Burn-up life

100 Sv

Operation mode setup time

1 min

Power supply and continuous run time


- Alternate or direct current mains

24 h

- Internal battery



24 h


12 h

Protection class


Working temperature range

-30°C ... +50°C

Relative humidity with air temperature ≤35°C without condensation


Overall dimensions

233x85x67 mm


0.9 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 without notice


The X-ray and gamma radiation dosimeters meet International standard requirements: IEC 60846-1:2009 Safety standard requirements: IEC 61010-1:1990

EMC requirements: EN 55022:1998+А1:2000+А2:2003, EN 55024:1998+A1:2001+A2:2003, IEC 61000-4-2:2001, IEC 61000-4-3:2008, IEC 61000-4-4:2004, IEC 61000-4-5:2005, IEC 61000-4-6:2006, IEC 61000-4-11:2004

The X-ray and gamma radiation dosimeters have the pattern approval certificates of Republic of Belarus, Russian Federation, Ukraine, Lithuania and Kazakhstan.

Download brochure809.32 KB
AT1121 Cerfificate, China409.77 KB
AT1123 Cerfificate, China416.89 KB