AlphaGUARD - Portable radon monitor

AlphaGUARD is a portable radon meter with high sensitivity, long time stable calibration (guaranteed for 5 years), outstanding accuracy and high storage capacity. Maintenance-free operation

It is the benchmark instrument for professional radon monitoring and accurate measurement on site in nuclear industry, health, research centers, construction and recycling sites, etc..

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AlphaGUARD is suitable as a reference device and offers the following features:

  • Quality at the highest level
  • Long-term stable calibration factor (guaranteed 5 years)
  • Calibration traceable to different national standards (PTB, NIST, NPL)
  • Inbuilt quality assurance system for permanent validation of system operation and data
  • Fast transient response
  • Automatic background correction
  • No sensitivity to high air humidity

AlphaGUARD incorporates a pulse-counting ionization chamber (alpha spectroscopy). Based on optimal chamber geometry and intelligent signal evaluation, this radon monitor is suitable for continuous monitoring of radon concentrations between 2 – 2 000 000 Bq/m³. The DSP (Digital Signal Processing) technology provides highly effective differentiation ability between “real” radon data and all kinds of artefacts.

In addition to the radon concentration in air, AlphaGUARD measures and records simultaneously the ambient temperature, relative humidity and atmospheric pressure with integrated sensors.

The complete product line provides all accessories for radon in air, water, soil, building materials, progeny, thoron and calibration equipment to perform air, water, soil and exhalation measurements. The collected data can be linked to the DataVIEW software, allowing data download and storage as well as professional data analysis and reporting.


0.62 L pulsed ionization chamber

Mode of operation

3D alpha spectroscopy and current mode

Radon measuring range

2 – 2,000,000 Bq/m³

Thoron measuring range

2 – 2,000,000 Bq/m³ (only for specific product version)

Measurement modes / detector filling system

Diffusion, flow or sampling (according to the product version)

Passive diffusion: 10 - 60 min

Flow mode: 1 - 10 min

Sampling: 10 min 

Instrument calibrator error

< 3%

Sensitivity of detector

5 cpm at 100 Bq/m3, (5 cpm at 3 pCi/l)

Sensitivity to gama radiation

No interference for Gamma environments below 0,2 mSv/h

Storage capacity

 Up to 60,000 measurement points

 ~ 400 days at 10 min measuring cycle

 ~ 2,500 days at 60 min measuring cycle


10 days (40 days with external battery)


Graphic display, backlight

EMC resistence

Standards IEC 61000-4-2/3/4/5/6/11

Conditions for use

-10°C to +50°C

700 mbar to 1100 mbar

0% RH to 95% RH (non – condensing)

Energy consumption

100 to 240V (400 mA)


Without handle 82 x 340 x 123 mm

With handle 329 x 355 x 123 mm


6,2 kg



Additional sensors

T, P, H, Reloc, QA, external sensors


  • Exhalation box
  • Alpha PM – radon progeny measurement kit
  • Aqua KIT – radon measurement kit in water for sampling
  • Soil probe for radon measurement in ground gas
  • Alpha PUMP/Lab PUMP – soil sampling kit and continuous radon water measurement system
  • Data View Pro software
  • Emanation/calibration vessel
  • Valve selector
  • Tyvek protective cover


ALPHAGUARD brochure  Brochure_AlphaGUARD_2022_web.pdf 
Portable radon monitor   
AlphaGUARD - Portable radon monitor
Portable radon monitor
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