Adsorption and Desorption of Radon in Argon Gas, and the Development of Low Level Radon Concentration Measurement Method

Abstract

We studied a method to measure low level radon concentration in the argon gas using a high sensitivity radon detector. Radon is collected by activated charcoal in a column with cooling system. It is confirmed that collection efficiency of radon in argon gas is higher than 90% with the activated charcoal cooled at −105°C. The measured release efficiency of radon in argon gas is higher than 99% at 85°C of the charcoal temperature. The background level of this system for argon is 14±1(stat.) ±1(sys.)mBq/m³. As a result, we estimate that the radon concentration of 14μBq/m³ in argon can be measured after 0.5 days of collection with flow rate 3.0L/min.