The partition coefficient (the ratio of radon concentration in the water to that in the air at equilibrium) is determined by the temperature at the air/water interface. This temperature is measured with a temperature probe inserted into the exchanger. At typical room temperature the coefficient is about 0.25. That means the concentration of radon in the air is four times higher than in the water. As a result, the system's sensitivity to radon in water is four times higher than the sensitivity to radon in air.

It takes time for the water to deliver radon to the air loop and for the RAD7 to respond to the changed radon concentration. With optimum configuration the response time of the system may be reduced to less than half an hour.

Product Highlights

• Radon and Thoron Measurement
  Continuously monitor both radon and thoron in water. 
  
  
• Simple to Use
  Just hook it up to the tap and hook it up to the RAD7.
  
  
• Fast
  95% response in 30 minutes. 
  
  
• Sensitive
  Easily measure radon concentrations below 1 pCi/L.
  
  
• Accurate
  Measurements are precise within +/- 5%.
  
  
• Clean and Safe
  Involves no hazardous materials or chemicals.
  
  
• Complete
  Includes temperature logger and necessary software. 
  
  
• Great Value
  Practically no running costs.

How it Works

Water passes continuously through the RAD AQUA exchanger. Air flows in a closed loop through the exchanger and through the RAD7. Radon in the air comes into equilibrium with radon in the water. From the radon concentration in the air and the temperature of the air/water interface, the radon concentration in the water is determined. This is the fastest, most sensitive method of measuring radon in water, and it can monitor both radon and thoron levels continuously.

Documentation

 RAD AQUA Manual (PDF)