モデルハウスの屋内・外自然空間放射線線量率の測定
1990 年 25 巻 4 号 p. 385-390
詳細
1990 年 25 巻 4 号 p. 385-390
Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of four housing centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5″φ×4″ NaI (Tl) scintillation counter and a 6″φ spherical plastic scintillation counter.
The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40% higher than that in fireproof wooden houses, about 60% higher than that in light-weight steel-framed buildings, in fireproof wooden houses, it was also about 10% higher than in light-weight steel-framed building.
The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be about 0.95±0.15, 0.77±0.10, and 0.72±0.13 for ferro-concrete buildings, fireproof wooden houses and light-weight steel-framed buildings, respectively.
The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8μR/h, about 18% lower than the outdoors. The indoor cosmic-ray exposure rate in fireproof wooden houses and light-weight steel-framed buildings were 3.2μR/h, about 6% lower than the outdoors.
