10:45 AM - 11:00 AM
[SCG56-01] Development of a Radon Isotope Monitor for Soil Gas Observation
Keywords:Radon, Isotope ratio
We have developed a continuous monitoring device for radon (Rn) isotope ratios that can be buried in the soi, and we will report on the details of this device.
The radon exhalated from soil includes 222Rn in the uranium series and 220Rn in the thorium series, with half-lives of 3.8 days and 56 seconds, respectively. The ratio of 222Rn concentration to 220Rn concentration, R222/220, is thought to reflect the advective distance of CO2, the carrier gas of Rn, due to the difference in their half-lives. Therefore, the radon isotope ratios of gases dissolved in hot spring water and gases exhalated from volcanic bodies may be used as indicators to monitor changes in hot spring dissolved gases and volcanic activity.
Most radon monitors available on the market are made overseas, and the models that can be used for scientific measurement are very expensive, costing nearly 2 million yen each. It is possible to install the device indoors for hot spring measurement, but it is too unsettling to leave it outdoors with the battery, like a volcanic field. Therefore, we aimed to develop a radon monitoring device with the same performance as commercial products, which would cost less than 100,000 yen per unit. As a result, we succeeded in creating a radon monitor that has a response speed equivalent to commercial products and a resolution four times higher, at a cost of about 1/20 of commercial products.
The radon exhalated from soil includes 222Rn in the uranium series and 220Rn in the thorium series, with half-lives of 3.8 days and 56 seconds, respectively. The ratio of 222Rn concentration to 220Rn concentration, R222/220, is thought to reflect the advective distance of CO2, the carrier gas of Rn, due to the difference in their half-lives. Therefore, the radon isotope ratios of gases dissolved in hot spring water and gases exhalated from volcanic bodies may be used as indicators to monitor changes in hot spring dissolved gases and volcanic activity.
Most radon monitors available on the market are made overseas, and the models that can be used for scientific measurement are very expensive, costing nearly 2 million yen each. It is possible to install the device indoors for hot spring measurement, but it is too unsettling to leave it outdoors with the battery, like a volcanic field. Therefore, we aimed to develop a radon monitoring device with the same performance as commercial products, which would cost less than 100,000 yen per unit. As a result, we succeeded in creating a radon monitor that has a response speed equivalent to commercial products and a resolution four times higher, at a cost of about 1/20 of commercial products.