Scavenged Pu-239, Pu-240, and Am-241 from snowfalls in the atmosphere settling on Mt. Zugspitze in 2014, 2015 and 2016

作者：Gueckel Katharina; Shinonaga Taeko; Christl Marcus; Tschiersch Jochen

来源：Scientific Reports, 2017, 7(1): 11848.

DOI：10.1038/s41598-017-12079-y

Concentrations of Pu-239, Pu-240, and Am-241, and atomic ratio of Pu-240/Pu-239 in freshly fallen snow on Mt. Zugspitze collected in 2014, 2015 and 2016 were determined by accelerator mass spectrometry (AMS). For the sub-femtogram (10(-15) g) - level of Pu and Am analysis, a chemical separation procedure combined with AMS was improved and an excellent overall efficiency of about 10(-4) was achieved. The concentration of Pu-239 ranges from 75 +/- 13 ag/kg to 2823 +/- 84 ag/kg, of Pu-240 from 20.6 +/- 5.2 to 601 +/- 21 ag/kg, and of Am-241 was found in the range of 16.7 +/- 5.0-218.8 +/- 8.9 ag/kg. Atomic ratios of Pu-240/Pu-239 for most samples are comparable to the fallout in middle Europe. One exceptional sample shows a higher Pu concentration. High airborne dust concentration, wind directions, high Cs concentrations and the activity ratio of Pu239+240/Cs-137 lead to the conclusion that the sample was influenced by Pu in Saharan dust transported to Mt. Zugspitze.

• 出版日期2017-9-19