Measurement of environmental gamma rays in Chubu district, Japan

Environmental gamma rays were measured by a glass dosimeter system and a sodium Iodide scintillation spectrometer for spot measurement and car-borne measurement during the period from June 1995 to February 1997. The glass dosimeters were placed on electric poles at a height of 2.5 meters in 29 locations. Comparing the results, there was little difference between the two as far as cosmic rays were concerned. According to the glass dosimeter readings, the absorbed dose rate in the air was found to range from 52 nGy·h-1 to 124 nGy·h-1. Long term monitoring showed that there were no fluctuations according to time except for the shielding effects caused by the accumulation of snow. (author)