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 หัวเรื่อง:ระดับความเข้มข้นของตะกั่ว -214 และบิสมัท -214 ในบรรยากาศบริเวณมหาวิทยาลัยเกษตรศาสตร์ ผู้เขียน: Rachanee Rugivarodom สื่อสิ่งพิมพ์:pdf AbstractBy gamma spectrometry of dusts in the atmosphere, the natural radioisotopes 214Pb and 214Bi were found. Samples of air were examined to ascertain the concentration per unit volume. Air particles were collected on fibre glass filters using a high volume jet air sampler. The two hundred-seventy air samples from six different locations at K.U. were monitored for gamma activities by a Hyper Pure Germanium (HPGe) detector. The gamma spectra were then examined and analyzed by microcomputer. The average concentrations of 214Pb and 214Bi in the atmosphere at K.U. were found to be (5.79+-0.62) x 10(superscript-12) ugm/m(superscript3) and 1.61+-0.31) x 10(superscript-11) ugm/m(superscript3) respectively. Safety standard of maximum concentration of 214Pb or 214Bi in the atmosphere is 1 x 10(superscript4) ugm/m(superscript3). The results show that the concentration of these isotopes is lower than the maximum of the safety standard. |
หัวเรื่อง:ผลกระทบของดอนเมืองโทลล์เวย์ต่อปริมาณตะกั่ว -214 และบิสมัท -214 ในบรรยากาศบริเวณมหาวิทยาลัยเกษตรศาสตร์ ผู้เขียน:Rachanee Rujivarodom สื่อสิ่งพิมพ์:pdf Abstract214Pb and 214Bi concentrations in the Don Muang Tollway atmosphere were measured using gamma spectrometer. Air particles were collected on glass fiber filters by using a high volume jet air sampler for 3 hours. The 540 air samples from six different locations in the Don Muang Tollway 2 times each for 3 months (7 Dec 1998-26 Feb 1999 and 1 Mar-21 May 1999) were monitored for gamma activities using a Hyper Pure Germanium (HPGe) detector. The average concentrations of 214Pb and 214Bi were (2.283 ? 0.015) ? 10-11 ?g/m3 and (2.683 ? 0.036) ? 10-11 ?g/m3, respectively. The concentration of 222Rn in secular equilibrium condition was also calculated from the concentration of 214Pb, giving an average value (4.867 ? 0.032) ? 10-9 ?g/m3. which are lower than the maximum values of the safety standards (1 ? 10-8 ?g/m3 for 214Pb and 214Bi, 2 ? 10-7 ?g/ m3 for 222Rn). The result of this study showed that 214Pb and 214Bi concentrations after building the Don Muang Tollway were about 10 times higher than the former condition in 1990. This also corresponds with the properties of the Earth atmosphere. |