Sequential measurements of energy spectrum and intensity for cosmic ray neutrons

摘要

The cosmic-ray neutron spectrum and dose rate has been measured with three neutron detectors, Bonner sphere, high-sensitivity rem counter and NE213 organic liquid scintillator continuously from October 2000 when the solar activity reached maximum. The neutron spectrum has three major peaks, thermal energy peak, evaporation peak around 1 MeV and cascade peak around 100 MeV. There can be seen a tendency that a cascade peak increases on the day of higher solar activity having higher neutron flux compared with the other two peaks. The time variation of neutron dose rate shows some correlation with the atmospheric pressure and the solar activity.