Production and behavior of beryllium 7 radionuclide in the upper atmosphere

Yoshimori, M.

doi:10.1016/j.asr.2005.04.093

Cited by 33 publications

(13 citation statements)

References 25 publications

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“…We have shown that the contribution of the photonuclear mechanism is commensurate with the contribution of the proton and neutron mechanisms (see, for example, [4,9,11]) of 7 Be production in the Earth's atmosphere, so that it is necessary to take the former into account in analyzing processes of accumulation and transfer of 7 Be in the bottom layer of the atmosphere.…”

Section: Integration Inmentioning

confidence: 96%

“…It is commonly believed that basic reactions leading to the production of beryllium isotopes in the Earth's atmosphere are induced by the interaction 1 of cosmic rays with nuclei of nitrogen and and oxygen [4], which are dominant constituents of atmospheric air. These are the so-called spallation reactions 14 N(p, X) 7 Be, 16 O(p, X) 7 Be, 14 N(n, X) 7 Be, and 16 O(n, X) 7 Be.…”

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confidence: 99%

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Photonuclear channel of 7Be production in the Earth’s atmosphere

et al. 2012

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Measurements of average values of cross sections for the А(γ, X) 7 Be photonuclear reactions on nitrogen, oxygen, and carbon of natural isotopic composition were performed in the energy range from the threshold to 90 MeV. On the basis of the measured cross sections for 7 Be photoproduction and on the basis of the results obtained by simulating the nuclear-electromagnetic cascade in the Earth's atmosphere, the contribution of the photonuclear mechanism to the production of the cosmogenic radioisotope 7 Be in the atmosphere and its latitude dependence were investigated for the first time. It is shown that the contribution of the photonuclear mechanism is commensurate with the contribution of the proton and neutron mechanisms of 7 Be production in the atmosphere and that the inclusion of this mechanism is mandatory in analyzing the accumulation and transfer of 7 Be in the planetary boundary layer.

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Section: Integration Inmentioning

confidence: 96%

mentioning

confidence: 99%

Photonuclear channel of 7Be production in the Earth’s atmosphere

et al. 2012

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“…It was determined that the volume activity of 7 Be changes in the second half of the 23rd cycle of solar activity, i.e., the yearly average 7 Be concentration increases toward the end of the cycle. Data were obtained on the seasonal dependence of the precipitation density and the volume activity of 7 Be on the meteorological parameters (temperature, amount of precipitation).Cosmogenic 7 Be (T 1/2 = 52.3 days) forms in nuclear spallation reactions when high-energy protons (∼1 GeV) when cosmic rays interact with nitrogen nuclei in the stratosphere 14 N + p → 7 Be (up to 70-80%) and secondary neutrons with nitrogen nuclei and oxygen in the troposphere 14 N + n → 7 Be and 16 O + n → 7 Be (up to 20-30%) [1,2]. During changes in the solar activity (number of sun spots -the Wolf number W) within the 11-year solar cycle and aperiodic bursts of solar activity, the geomagnetic field changes, cosmic rays are deflected and, correspondingly, the 7 Be production rate changes [3].…”

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confidence: 99%

“…Cosmogenic 7 Be (T 1/2 = 52.3 days) forms in nuclear spallation reactions when high-energy protons (∼1 GeV) when cosmic rays interact with nitrogen nuclei in the stratosphere 14 N + p → 7 Be (up to 70-80%) and secondary neutrons with nitrogen nuclei and oxygen in the troposphere 14 N + n → 7 Be and 16 O + n → 7 Be (up to 20-30%) [1,2]. During changes in the solar activity (number of sun spots -the Wolf number W) within the 11-year solar cycle and aperiodic bursts of solar activity, the geomagnetic field changes, cosmic rays are deflected and, correspondingly, the 7 Be production rate changes [3].…”

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confidence: 99%

“…The 7 Be content was measured in aerosols (once per week) and precipitation (once per month) was monitored as part of the monitoring of the radioactivity of the atmospheric layer near the ground in Rostovon-Don in 2001-2005. Data were obtained on the correlations between the 7 Be volume activity in aerosols and the Wolf number, temperature, and amount of precipitation.…”

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Content of cosmogenic 7Be in the air layer at the ground at temperate latitudes

et al. 2007

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The 7 Be content was measured in aerosols (once per week) and precipitation (once per month) was monitored as part of the monitoring of the radioactivity of the atmospheric layer near the ground in Rostovon-Don in 2001-2005. Data were obtained on the correlations between the 7 Be volume activity in aerosols and the Wolf number, temperature, and amount of precipitation. The highest correlation coefficients were observed during the spring (k = 1). It was determined that the volume activity of 7 Be changes in the second half of the 23rd cycle of solar activity, i.e., the yearly average 7 Be concentration increases toward the end of the cycle. Data were obtained on the seasonal dependence of the precipitation density and the volume activity of 7 Be on the meteorological parameters (temperature, amount of precipitation).Cosmogenic 7 Be (T 1/2 = 52.3 days) forms in nuclear spallation reactions when high-energy protons (∼1 GeV) when cosmic rays interact with nitrogen nuclei in the stratosphere 14 N + p → 7 Be (up to 70-80%) and secondary neutrons with nitrogen nuclei and oxygen in the troposphere 14 N + n → 7 Be and 16 O + n → 7 Be (up to 20-30%) [1,2]. During changes in the solar activity (number of sun spots -the Wolf number W) within the 11-year solar cycle and aperiodic bursts of solar activity, the geomagnetic field changes, cosmic rays are deflected and, correspondingly, the 7 Be production rate changes [3]. A decrease of the 7 Be production rate corresponds to an increase of solar activity (increase of the Wolf number) and vice versa, i.e., there is an anticorrelation between the 7 Be content in the atmospheric air and the Wolf number with coefficient k = −0.81 according to [4] and k = −0.83 ± 0.03 according to the data in [5]. Over the 11-year solar cycle, the yearly average content at the maximum and minimum differs by approximately 45%. The 7 Be production rate also depends on the geographical coordinates of the observations station because of the effect of the Earth's magnetic field on the cosmic ray distribution.Long (more than two cycles of solar activity) systematic measurements on the global network of stations must be performed in order to determine reliably the relation between the 7 Be volume activity in the air layer at the ground and the solar activity against the background of variations of a different origin. The results of the determination of 7 Be in the atmosphere in 1974-1999 at 26 stations were analyzed in [3]. The existence of the anticorrelation indicated above, which explains about 54% of all temporal variations of the 7 Be for stations in Australia, New Zealand, and North America and only 18% of the variations for the stations in South America and Antarctica, has been proven. Long-time measurements (1987Long-time measurements ( -2003 were performed recently at temperate latitudes (40°38′) [6]. Under especially favorable conditions (regularity of measurements of the meteorological parameters, absence of any effect due to some of them, and so forth), a correlation between the 7 Be content an...

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