# Monitoring Method for an Ambient Gamma Exposure Rate and Its Measurement Analysis

• Lee, Mo-Sung (Department of Physics with Computer, CheongJu University) ;
• Woo, Jong-Kwan (Department of Physics, University of Seoul City)
• Published : 2006.12.30

#### Abstract

Daily and seasonal variations of the ambient gamma ray exposure rates were measured by using a pressurized ion chamber from January 2003 to December 2005 in the CheongJu Regional Radiation Monitoring Post and the patterns of the distributions were studied. The annual average of the daily variation of the exposure rate was $\sim0.17{\mu}R/h$. The exposure rate was found to be maximum during 8:00 am to 9:00 am and minimum during 8:00 pm to 10:00 pm. For the annual data, the exposure rate was the minimum during the month of February. The exposure rate increased from February to mid-October (except during the period from May to July with no change) and decreased from October to February. The seasonal variation was found to be about $1{\mu}R/h$. Most of the measured values (96%) of the exposure rates fell under the normal distribution with a deviation of less than 4.8% and the remaining 4% had large fluctuations caused mainly by the rainfalls.

#### References

1. 과학기술부. 원자력이용시설 주변의 방사선환경조사 및 방사선환경영향평가에 관한 규정. 과학기술부고시. 2004; 제2004-17호