Błażej Sylwia, Mietelski Jerzy W
The Henryk Niewodniczański Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
J Radioanal Nucl Chem. 2014;300(2):747-756. doi: 10.1007/s10967-014-3049-6. Epub 2014 Mar 9.
A low background gamma spectrometer with an Etruscan, 2500 years old lead shield and a muon veto detector were applied to study Na and Be activity concentration in ground level air aerosol samples collected weekly over the years 2003-2006 in Kraków. Each sample was formed with ca 100 000 m of passed air, collected with two parallel ASS-500 high volume air samplers. The results for K and Cs are also presented for reference and comparison. Presented frequency distributions for activity concentration and correlation between the obtained results are discussed. The activity concentration results confirmed seasonal variation of activity to be different for all the investigated radionuclides. Moreover, the seasonal variation in nucleus activity ratio was also noticed for Na and Be. Cosmogenic radionuclides being mainly of stratospheric origin, are subsequently attached to fine aerosols, via which they are transported to the ground level air. The mean aerosol transport time within the troposphere was estimated as equal to 7.5 days on average, reaching even 50 days in warm seasons. Limitations of the applied model were identified.
一台配备有2500年前伊特鲁里亚铅屏蔽和μ子 veto探测器的低本底伽马能谱仪，被用于研究2003年至2006年期间每周在克拉科夫采集的地面空气气溶胶样品中的钠和铍活度浓度。每个样品由大约100000立方米通过的空气形成，用两个平行的ASS - 500大容量空气采样器收集。还给出了钾和铯的结果以供参考和比较。讨论了所呈现的活度浓度频率分布以及所得结果之间的相关性。活度浓度结果证实，所有研究的放射性核素的活度季节性变化各不相同。此外，还注意到钠和铍的核活度比存在季节性变化。宇宙成因放射性核素主要起源于平流层，随后附着在细气溶胶上，通过细气溶胶被输送到地面空气。对流层内气溶胶的平均传输时间估计平均等于7.5天，在温暖季节甚至可达50天。确定了所应用模型的局限性。
