Establishment of a Mid-Latitude Neutron Monitoring Site at Mt. Gamak in Korea

Abstract

Cosmic ray neutron monitors (NMs) are ground-based detectors that measure secondary neutrons produced by primary cosmic ray particles in the energy range of approximately 500 MeV to several GeV. South Korea operates two NMs: one at Jang Bogo Station in Antarctica and another recently relocated from Daejeon to Mt. Gamak in Geochang, now managed by the Korea Astronomy and Space Science Institute (KASI). Mt. Gamak is geographically comparable to the former Daejeon site, located approximately 100 km to the southeast. The NM at Mt. Gamak’s altitude is approximately 925 meters, which is about four times higher than that of the Daejeon site. In addition, the average atmospheric pressure at Mt. Gamak was 915.9 hPa, about 85 hPa lower than that of Daejeon. The barometric coefficient was approximately –0.7101%/hPa. As a result, the NM at Mt. Gamak records more than twice the count rate observed at the Daejeon site. Given these conditions, the Mt. Gamak NM is expected to play a crucial role in cosmic ray research and in monitoring the solar and space environment in the mid-latitude region.