2009 Volume 44 Issue 1 Pages 66-71
In order to estimate the environmental radiation dose rate level, measurements of the terrestrial gamma ray dose rates and cosmic ray ionizing components were conducted in public places such as park, street and train in Tokyo area. Measurements for 10 s with a NaI(Tl) scintillation spectrometer were repeatedly carried out with walking. Terrestrial gamma ray dose rate ranges from 10 nSv/h in a train to 80 nSv/h on the stone road. Although cosmic ray ionizing component was constantly 30 nSv/h in the outdoor, reductions by shielding effect were observed at underground and in the concrete building. Influence of radiopharmaceutical was measured in the stations where so many people exist. This shows that the same effect may occur in the environmental radiation monitoring.
