By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil （230 S, 450 W） using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these m...By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil （230 S, 450 W） using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these measures. The observation confirms the existence of a periodicity of 24 hours through the technique （Fast Fourier Transform） applied to the data set, and this cycle can be better visible in longer dry periods. On rainy days or with heavy fog in the region, this periodicity is modified or even disappears. As Geiger do not detect alpha particles due to absorption in the walls of the sensor tube, it measured X and gamma rays coming from the radon gas progeny. Radon gas （222Rn） has a half-life of 19.7 minutes to decays in 214Bi emitting gamma ray energy （45%） with 0.609 MeV which is monitored daily by Geiger. Also 222Rn decays in 26.8 minutes in 214pb giving （37%） with 0.35 MeV and others with less energy. It is confirmed the good performance ofa Geiger tube with LND 712 working with about 500 VDC rated voltage.展开更多
Indoor radon levels were measured in 221 homes in rented accommodation. In addition, buildings were registered for a series of variables describing building characteristics and used materials. The mean year value of t...Indoor radon levels were measured in 221 homes in rented accommodation. In addition, buildings were registered for a series of variables describing building characteristics and used materials. The mean year value of the indoor radon level was 30.7 （1~250） Bq/m3. The indoor radon level exceeded 100 Bq/m3 in 5.9% of the homes. Of the investigated variables, only homes in single-family terraced houses, were statistically significant. Approx： 75% of homes exceeding 100 Bq/m3 indoor radon level had levels between 100 and 200 Bq/m3 and 25% had indoor radon levels exceeding 200 Bq/m3. Significant differences in indoor radon levels were found in homes located in multi-occupant houses. Additionally, the risk of indoor radon levels exceeding 100 Bq/m3 in homes in multi-occupant houses was found to be very low, but the risk was the highest on the ground floor in a building constructed with slab on ground.展开更多
文摘By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil （230 S, 450 W） using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these measures. The observation confirms the existence of a periodicity of 24 hours through the technique （Fast Fourier Transform） applied to the data set, and this cycle can be better visible in longer dry periods. On rainy days or with heavy fog in the region, this periodicity is modified or even disappears. As Geiger do not detect alpha particles due to absorption in the walls of the sensor tube, it measured X and gamma rays coming from the radon gas progeny. Radon gas （222Rn） has a half-life of 19.7 minutes to decays in 214Bi emitting gamma ray energy （45%） with 0.609 MeV which is monitored daily by Geiger. Also 222Rn decays in 26.8 minutes in 214pb giving （37%） with 0.35 MeV and others with less energy. It is confirmed the good performance ofa Geiger tube with LND 712 working with about 500 VDC rated voltage.
文摘Indoor radon levels were measured in 221 homes in rented accommodation. In addition, buildings were registered for a series of variables describing building characteristics and used materials. The mean year value of the indoor radon level was 30.7 （1~250） Bq/m3. The indoor radon level exceeded 100 Bq/m3 in 5.9% of the homes. Of the investigated variables, only homes in single-family terraced houses, were statistically significant. Approx： 75% of homes exceeding 100 Bq/m3 indoor radon level had levels between 100 and 200 Bq/m3 and 25% had indoor radon levels exceeding 200 Bq/m3. Significant differences in indoor radon levels were found in homes located in multi-occupant houses. Additionally, the risk of indoor radon levels exceeding 100 Bq/m3 in homes in multi-occupant houses was found to be very low, but the risk was the highest on the ground floor in a building constructed with slab on ground.
