Abstract: By taking part in a comparison measurement held at Hedi reservoir in Lianjiang City, Guangdong Province, the values ofcosmic ray response factor were further verified for six RSS-131 high pressureionization chambers in use in Guangdong Environmental Radiation Monitoring Center (GERC). The results show that the value range is 0.609－0.713, with an average of 0.651 and a standard deviation of 0.036. It indicates that the cosmic ray response factor is stable, and, with theoretical calculations combined, can be easily obtained for different regions, so as to solve the difficulties in cosmic ray measurement.

Key words: High pressure ionization chamber, Cosmic ray, Response factor