Development of a technique for the measurement of the radon exhalation rate using an activated charcoal collector.
A simple system to evaluate the 222Rn (radon) exhalation rate from soil has been improved. A sampling cuvette of 2.1 L is placed so that it covers the targeted ground soil, and radon emanating from the soil accumulates within the cuvette for 24 h. Its internal radon concentration is measured by the combination of an activated charcoal (PICO-RAD) and a liquid scintillation counting system. This study shows variations of the conversion factor (CF: unit Bq m(-3)/cpm) of PICO-RAD. The range of CF due to temperature (10-30 degrees C) was between -21% and +69%, and this due to humidity (30-90%) was between 0% and -15%. Humidity and radon concentration in the cuvette covering soil tended to saturate in a few hours. The above information was used to correct the CF for the evaluation. The improved system shows high reliability and can be easily applied to natural environments.
Iimoto
Takeshi
T
Graduate School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Tokyo 113-0032, Japan. iimoto@n.t.u-tokyo.ac.jp
Akasaka
Yoshinori
Y
Koike
Yuya
Y
Kosako
Toshiso
T
D000396:Air Pollutants, Radioactive; D016902:Air Pollution, Indoor; D002606:Charcoal; D004867:Equipment Design; D006813:Humidity; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods; D011886:Radon; D015203:Reproducibility of Results; D012588:Scintillation Counting; D012990:Soil Pollutants, Radioactive; D013696:Temperature; D013997:Time Factors
D000396:Air Pollutants, Radioactive; D012990:Soil Pollutants, Radioactive; D002606:Charcoal; D011886:Radon