We report monthly averages of weekly (7)Be and (22)Na concentrations in aerosol samples collected with high volume aerosol filters at 5 sampling sites in Switzerland from 1994 to 2011 ((7)Be) and from 2000 to 2011 ((22)Na). Monthly average concentrations of the two cosmogenic isotopes varied between 2600 and 4600 μBq/m(3) for (7)Be and between 0.2 μBq/m(3) and 0.5 μBq/m(3) for (22)Na. The (22)Na concentration in ground level air strongly increased from March to May, while a corresponding (7)Be increase was seen from March until July. The observed variations of the (7)Be and (22)Na activities together with the changes in the (7)Be/(22)Na ratio indicate input of stratospheric air between March and May, increased mixing of upper tropospheric air from June to August, and less exchange between the upper and lower troposphere in autumn and winter. Additionally, the 11-year solar cycle is clearly seen in the annual averages of the (7)Be concentrations.
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http://dx.doi.org/10.1016/j.jenvrad.2013.03.012 | DOI Listing |
Biomol Concepts
January 2023
Istituto Officina dei Materiali, CNR-IOM Cagliari, Cittadella Universitaria, Monserrato (CA) 09042-I, Italy.
B isotopes have been almost exclusively used in the neutron-capture radiation therapy (NCT) of cancer for decades. We have identified two other nuclides suitable for radiotherapy, which have ca. ten times larger cross section of absorption for neutrons and emit heavy charged particles.
View Article and Find Full Text PDFJ Environ Radioact
February 2023
Savannah River National Laboratory, Aiken, SC, 29808, United States.
Ultra-low-level measurements of radionuclides in air have been conducted at the Savannah River National Laboratory (SRNL) to determine the atmospheric concentration of fission products released following the Fukushima Daiichi reactor accident on March 11, 2011. Air filter samples were acquired from two high-volume collection systems (a traditional filter-based system and an electrostatic precipitator-based system) to monitor airborne radionuclide concentrations in the period covering from 2 weeks to 3 years after the disaster. The world-wide spread of low-level concentrations of airborne fission products from the Fukushima event provided a unique opportunity to demonstrate SRNL's electrostatic particle collection technology and other improvements in environmental monitoring developed at the Savannah River Site (SRS).
View Article and Find Full Text PDFArh Hig Rada Toksikol
December 2019
Jožef Stefan Institute, Ljubljana, Slovenia.
This article presents yearly mean concentrations of cosmogenic radionuclides 7Be and 22Na occurring in dry and wet depositions (fallout) and aerosols. Time dependencies negatively correlated with the yearly mean number of sunspots. Activity concentrations of 7Be and 22Na in aerosols in the surface air had a correlation of near-unity.
View Article and Find Full Text PDFJ Environ Radioact
February 2019
LARUEX, Environmental Radioactivity Laboratory, Dpt. Applied Physics, Faculty of Veterinary Sciences, Avda. Universidad, s/n, 10003, Cáceres, Spain. Electronic address:
Cosmogenic radionuclides provide information about air masses exchanges between stratosphere and troposphere. The Be concentration in aerosols usually shows a seasonal variability, depending also of the climatic conditions. There are, however, fewer data available of the behavior of other cosmogenic radionuclides, such as Be and Na.
View Article and Find Full Text PDFJ Environ Radioact
December 2018
Radiation Protection Bureau of Health Canada, 775 Brookfield Road, Ottawa, Ontario, K1A 1C1, Canada.
Using a previously developed digital gamma-gamma coincidence/anticoincidence spectrometer, daily aerosol samples collected at Resolute Bay, Canada (74.71°N, 94.97°W) from May 2016 to April 2017 were analysed for activity concentrations of Na and Be.
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