Characteristics of the 18-tube NM64-type Daejeon neutron monitor in Korea

Abstract

The amount of cosmic radiation entering Earth's atmosphere is determined by, and is therefore an indicator of, the level of solar activity. As solar activity approaches a maximum, the importance of monitoring cosmic rays and researching their effects and our dose levels increases. The aim of this study was to install the NM64 neutron monitor and to measure its characteristics by using two different methods: analyzing the barometric coefficient and observing the diurnal variation. A neutron monitor was installed for the first time in Korea at the Korea Research Institute of Standard Science in 2011 with a rigidity cutoff of 11.2 GV. The barometric coefficient and the diurnal variation were analyzed with data for the interval Dec. 1-31, 2011. A reliable barometric coefficient was determined, -0.6557 +/- 0.0044%/hPa, and the diurnal variation was observed. The Daejeon neutron monitor worked correctly, given that the diurnal variation was hard to observe when the variation was small (in this case, less than 1%).