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Friedhelm Von Blanckenburg - One of the best experts on this subject based on the ideXlab platform.
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cosmogenic nuclides dates and rates of earth surface change
Elements, 2014Co-Authors: Friedhelm Von Blanckenburg, Jane K. WillenbringAbstract:Cosmogenic nuclides are very rare isotopes that are produced when particles generated in supernovas in our galaxy hit the atmosphere and then the Earth's surface. When the rocks and soils in this thin, ever-changing surface layer are bombarded by such Cosmic radiation, the nuclide clock begins to tick, thus providing dates and rates of Earth-surface processes. The measurement of cosmogenic nuclides tells us when earthquakes created topography at faults, when changing climate led to the growth of glaciers, how fast rivers grind mountains down, and how fast rocks weather to soil and withdraw atmospheric CO2. The use of cosmogenic nuclides is currently revolutionizing our understanding of Earth-surface processes and has significant implications for many Earth science disciplines. * Accelerator mass spectrometer (AMS) : Detection system that first accelerates ions to MeV-level energy and then separates them by mass. The technique measures the extremely small number of rare cosmogenic nuclides relative to a stable reference nuclide present in known amounts. Cosmic ray attenuation mean free path and attenuation depth scale : The depth, Λ, at which the intensity of Cosmic Rays is reduced by a factor of 1/e by interaction with material (units: g cm-2). 150 g cm-2 corresponds to an attenuation depth, z* = Λ/ρ, of 600 mm in silicate rock whose density (ρ) is 2.6 g cm-3. Cosmic Rays, primary : High-energy (0.1 to 1020 GeV) galactic particles that are composed primarily of protons (83%), α-particles (13%), and heavier nuclei (1%) Cosmic Rays, Secondary : Nucleons (neutrons, protons) and muons of 0.1 to 500 MeV energy that are produced by interactions between primary Cosmic Rays and molecules in the Earth's atmosphere. Secondary Cosmic Rays form a cascade of particles whose flux decreases with increasing atmospheric pressure. Cosmogenic nuclides, in situ : Nuclides that are produced by interaction of Secondary Cosmic Rays with solids (spallation, negative muon capture) at the Earth's surface. Other acronyms frequently used are TCN (terrestrial cosmogenic nuclides) and CRN (cosmogenic radioactive nuclides). Cosmogenic nuclides, meteoric : Cosmogenic nuclides that are produced in the atmosphere, the flux of some of which (e.g. meteoric 10Be) is ca 103 times greater than the production rate of in situ cosmogenic nuclides. Cosmogenic nuclides, radioactive : Cosmogenic nuclides that decay, and are therefore usually absent in eroding Earth materials prior to exposure (e.g. 10Be, 14C, 26Al, 36Cl) Cosmogenic nuclides, stable : Cosmogenic nuclides that are stable, and therefore might be present in eroding surface material from previous exposure episodes. These cosmogenic nuclides are the rare gases (e.g. 3He, 21Ne, 22Ne). Denudation rate : The total rate of removal of mass from the Earth's surface. It is the combined effect of physical (erosion rate) and chemical (weathering rate) processes. Electron volt (eV) : Energy of the charge of a single electron moved across an electric potential difference of one volt. MeV = mega–electron volt, one million eV. Erosion rate : The rate of removal of material from the Earth's surface by mechanical processes Fault : A planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of Earth movement Geomagnetic latitude : Analogous to geographic latitude, except that bearing is with respect to the magnetic pole, which changes through time, as opposed to the geographic pole Moraine : Debris that forms at the margins of a glacier Muon : A low-mass particle from Cosmic radiation that is able to penetrate deeper into the Earth's surface than neutrons due to the low probability that it will interact with target atoms Nucleons : the particles that make up atomic nuclei: neutrons and protons Production rate : The rate at which in situ cosmogenic nuclides are produced in a given mass of chemically defined target material in a given time [units: atoms g-1 (mineral) y-1]. For meteoric cosmogenic nuclides a flux is used [units: atoms cm-2 y-1]. Regolith : The mantle of weathered material overlying bedrock Soil : A mixture of regolith and weathered material from below with organic matter, dust, and chemical precipitates from above Spallation : The ejection of nucleons due to impact causing production of a different nuclide without fission of the product Weathering rate : Partial dissolution of bedrock by surficial fluids, and removal of soluble ions in solution
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the control mechanisms of erosion and weathering at basin scale from cosmogenic nuclides in river sediment
Earth and Planetary Science Letters, 2005Co-Authors: Friedhelm Von BlanckenburgAbstract:The study of a sample of river sediment enables the determination of spatially averaged denudation rates that provide an exceptional perspective on erosion and weathering processes that have taken place within a landscape. These measurements are done with in-situ produced cosmogenic nuclides (e.g. 10Be, 26Al), mostly in quartz from alluvial sediment. Cosmogenic nuclides are produced when Secondary Cosmic Rays interact with the very uppermost layer of the Earth's surface. They are produced within a characteristic depth scale of about 1 m, which means that the measured concentrations record an integrated denudation history while material passed through this depth interval. Depending on the denudation rate the resulting integration time scales are 103 to 105 years, and one obtains a robust long-term estimate of natural denudation that is relatively insensitive to short-term changes. The last 10 years have seen significant research activity using these methods, and an array of fascinating tectono-geomorphologic and geochemical insights are emerging. Amongst these is the ability to identify the physical and chemical processes with which a landscape responds to tectonic activity or climate change. A compilation of world-wide denudation rates in non-glaciated areas, that however, does not yet include some of the world's most active mountain belts, has resulted in the following findings, some of which have been unexpected: (1) No obvious relationship between precipitation or mean annual temperature and total denudation is apparent. (2) Topographic relief alone does not result in high rates of denudation. (3) Denudation rates are high in areas of landscape rejuvenation; that is triggered and controlled by tectonic activity (faulting, escarpment formation and retreat, rifting, surface uplift). (4) Rates of weathering (using a combination of cosmogenic nuclides and zirconium-normalised cation loss balances) co-vary primarily with physical erosion rates and much less with temperature or precipitation. (5) In some areas of high land use short-term rates (from river load gauging) exceed those from cosmogenic nuclides by several orders of magnitude, which serves to highlight the severity of geomorphic change caused by human action. In the future, the control mechanisms over denudation will be determined on all spatial scales, ranging from the single soil section to entire river basins. The same analysis can be done back through time on well-dated terraces, lake records, and marine sediment cores, which is possible with 10Be for the past 1–2 My. The rates obtained will be used to develop a quantitative understanding of tectonic, geomorphologic, and geochemical landscape processes, which in turn is a prerequisite to design and calibrate models of the response of landscapes to tectonic, climate, and anthropogenic forcing.
M. Aguilar - One of the best experts on this subject based on the ideXlab platform.
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properties of heavy Secondary fluorine Cosmic Rays results from the alpha magnetic spectrometer
Physical Review Letters, 2021Co-Authors: M. Aguilar, N. Attig, F. Barao, G Ambrosi, L Arruda, Ali L Cavasonza, M S Allen, B Alpat, L Barrin, A BartoloniAbstract:Precise knowledge of the charge and rigidity dependence of the Secondary Cosmic ray fluxes and the Secondary-to-primary flux ratios is essential in the understanding of Cosmic ray propagation. We report the properties of heavy Secondary Cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier Secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy Cosmic Rays, from F to Si, are different from those of light Cosmic Rays, from He to O, and that the Secondary Cosmic Rays have two classes.
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observation of new properties of Secondary Cosmic Rays lithium beryllium and boron by the alpha magnetic spectrometer on the international space station
Physical Review Letters, 2018Co-Authors: M. Aguilar, N. Attig, F. Barao, G Ambrosi, L Arruda, P Azzarello, A Bachlechner, Ali L Cavasonza, S Aupetit, A BarrauAbstract:: We report on the observation of new properties of Secondary Cosmic Rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of 5.4×10^{6} nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of 2.0±0.1. The three fluxes deviate from a single power law above 200 GV in an identical way. This behavior of Secondary Cosmic Rays has also been observed in the AMS measurement of primary Cosmic Rays He, C, and O but the rigidity dependences of primary Cosmic Rays and of Secondary Cosmic Rays are distinctly different. In particular, above 200 GV, the Secondary Cosmic Rays harden more than the primary Cosmic Rays.
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Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station
Phys.Rev.Lett., 2018Co-Authors: M. Aguilar, N. Attig, G Ambrosi, L Arruda, P Azzarello, A Bachlechner, S Aupetit, B Alpat, L. Ali Cavasonza, F. BaraoAbstract:A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on $2.2 \times 10^6$ events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O Cosmic Rays above $\sim 700$ GV. We observed that the nitrogen flux $\Phi_N$ can be presented as the sum of its primary component $\Phi_N^P$ and Secondary component $\Phi_N^S$, $\Phi_N = \Phi_N^P + \Phi_N^S$, and we found $\Phi_N$ is well described by the weighted sum of the oxygen flux $\Phi_O$ (primary Cosmic Rays) and the boron flux $\Phi_B$ (Secondary Cosmic Rays), with $\Phi_N^P = (0.090 \pm 0.002) \times \Phi_O$ and $\Phi_N^S = (0.62 \pm 0.02) \times \Phi_B$ over the entire rigidity range. This corresponds to a change of the contribution of the Secondary Cosmic ray component in the nitrogen flux from 70% at a few GV to $\lt 30 \%$ above 1 TV.
Jane K. Willenbring - One of the best experts on this subject based on the ideXlab platform.
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cosmogenic nuclides dates and rates of earth surface change
Elements, 2014Co-Authors: Friedhelm Von Blanckenburg, Jane K. WillenbringAbstract:Cosmogenic nuclides are very rare isotopes that are produced when particles generated in supernovas in our galaxy hit the atmosphere and then the Earth's surface. When the rocks and soils in this thin, ever-changing surface layer are bombarded by such Cosmic radiation, the nuclide clock begins to tick, thus providing dates and rates of Earth-surface processes. The measurement of cosmogenic nuclides tells us when earthquakes created topography at faults, when changing climate led to the growth of glaciers, how fast rivers grind mountains down, and how fast rocks weather to soil and withdraw atmospheric CO2. The use of cosmogenic nuclides is currently revolutionizing our understanding of Earth-surface processes and has significant implications for many Earth science disciplines. * Accelerator mass spectrometer (AMS) : Detection system that first accelerates ions to MeV-level energy and then separates them by mass. The technique measures the extremely small number of rare cosmogenic nuclides relative to a stable reference nuclide present in known amounts. Cosmic ray attenuation mean free path and attenuation depth scale : The depth, Λ, at which the intensity of Cosmic Rays is reduced by a factor of 1/e by interaction with material (units: g cm-2). 150 g cm-2 corresponds to an attenuation depth, z* = Λ/ρ, of 600 mm in silicate rock whose density (ρ) is 2.6 g cm-3. Cosmic Rays, primary : High-energy (0.1 to 1020 GeV) galactic particles that are composed primarily of protons (83%), α-particles (13%), and heavier nuclei (1%) Cosmic Rays, Secondary : Nucleons (neutrons, protons) and muons of 0.1 to 500 MeV energy that are produced by interactions between primary Cosmic Rays and molecules in the Earth's atmosphere. Secondary Cosmic Rays form a cascade of particles whose flux decreases with increasing atmospheric pressure. Cosmogenic nuclides, in situ : Nuclides that are produced by interaction of Secondary Cosmic Rays with solids (spallation, negative muon capture) at the Earth's surface. Other acronyms frequently used are TCN (terrestrial cosmogenic nuclides) and CRN (cosmogenic radioactive nuclides). Cosmogenic nuclides, meteoric : Cosmogenic nuclides that are produced in the atmosphere, the flux of some of which (e.g. meteoric 10Be) is ca 103 times greater than the production rate of in situ cosmogenic nuclides. Cosmogenic nuclides, radioactive : Cosmogenic nuclides that decay, and are therefore usually absent in eroding Earth materials prior to exposure (e.g. 10Be, 14C, 26Al, 36Cl) Cosmogenic nuclides, stable : Cosmogenic nuclides that are stable, and therefore might be present in eroding surface material from previous exposure episodes. These cosmogenic nuclides are the rare gases (e.g. 3He, 21Ne, 22Ne). Denudation rate : The total rate of removal of mass from the Earth's surface. It is the combined effect of physical (erosion rate) and chemical (weathering rate) processes. Electron volt (eV) : Energy of the charge of a single electron moved across an electric potential difference of one volt. MeV = mega–electron volt, one million eV. Erosion rate : The rate of removal of material from the Earth's surface by mechanical processes Fault : A planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of Earth movement Geomagnetic latitude : Analogous to geographic latitude, except that bearing is with respect to the magnetic pole, which changes through time, as opposed to the geographic pole Moraine : Debris that forms at the margins of a glacier Muon : A low-mass particle from Cosmic radiation that is able to penetrate deeper into the Earth's surface than neutrons due to the low probability that it will interact with target atoms Nucleons : the particles that make up atomic nuclei: neutrons and protons Production rate : The rate at which in situ cosmogenic nuclides are produced in a given mass of chemically defined target material in a given time [units: atoms g-1 (mineral) y-1]. For meteoric cosmogenic nuclides a flux is used [units: atoms cm-2 y-1]. Regolith : The mantle of weathered material overlying bedrock Soil : A mixture of regolith and weathered material from below with organic matter, dust, and chemical precipitates from above Spallation : The ejection of nucleons due to impact causing production of a different nuclide without fission of the product Weathering rate : Partial dissolution of bedrock by surficial fluids, and removal of soluble ions in solution
F. Barao - One of the best experts on this subject based on the ideXlab platform.
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properties of heavy Secondary fluorine Cosmic Rays results from the alpha magnetic spectrometer
Physical Review Letters, 2021Co-Authors: M. Aguilar, N. Attig, F. Barao, G Ambrosi, L Arruda, Ali L Cavasonza, M S Allen, B Alpat, L Barrin, A BartoloniAbstract:Precise knowledge of the charge and rigidity dependence of the Secondary Cosmic ray fluxes and the Secondary-to-primary flux ratios is essential in the understanding of Cosmic ray propagation. We report the properties of heavy Secondary Cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier Secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy Cosmic Rays, from F to Si, are different from those of light Cosmic Rays, from He to O, and that the Secondary Cosmic Rays have two classes.
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observation of new properties of Secondary Cosmic Rays lithium beryllium and boron by the alpha magnetic spectrometer on the international space station
Physical Review Letters, 2018Co-Authors: M. Aguilar, N. Attig, F. Barao, G Ambrosi, L Arruda, P Azzarello, A Bachlechner, Ali L Cavasonza, S Aupetit, A BarrauAbstract:: We report on the observation of new properties of Secondary Cosmic Rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of 5.4×10^{6} nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of 2.0±0.1. The three fluxes deviate from a single power law above 200 GV in an identical way. This behavior of Secondary Cosmic Rays has also been observed in the AMS measurement of primary Cosmic Rays He, C, and O but the rigidity dependences of primary Cosmic Rays and of Secondary Cosmic Rays are distinctly different. In particular, above 200 GV, the Secondary Cosmic Rays harden more than the primary Cosmic Rays.
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Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station
Phys.Rev.Lett., 2018Co-Authors: M. Aguilar, N. Attig, G Ambrosi, L Arruda, P Azzarello, A Bachlechner, S Aupetit, B Alpat, L. Ali Cavasonza, F. BaraoAbstract:A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on $2.2 \times 10^6$ events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O Cosmic Rays above $\sim 700$ GV. We observed that the nitrogen flux $\Phi_N$ can be presented as the sum of its primary component $\Phi_N^P$ and Secondary component $\Phi_N^S$, $\Phi_N = \Phi_N^P + \Phi_N^S$, and we found $\Phi_N$ is well described by the weighted sum of the oxygen flux $\Phi_O$ (primary Cosmic Rays) and the boron flux $\Phi_B$ (Secondary Cosmic Rays), with $\Phi_N^P = (0.090 \pm 0.002) \times \Phi_O$ and $\Phi_N^S = (0.62 \pm 0.02) \times \Phi_B$ over the entire rigidity range. This corresponds to a change of the contribution of the Secondary Cosmic ray component in the nitrogen flux from 70% at a few GV to $\lt 30 \%$ above 1 TV.
J Base - One of the best experts on this subject based on the ideXlab platform.
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significant enhancements of Secondary Cosmic Rays and electric field at the high mountain peak of lomnický stit in high tatras during thunderstorms
Earth Planets and Space, 2020Co-Authors: Jaroslav Chum, Ronald Langer, M Kollarik, I Strharský, J Base, Gerhard Diendorfer, Jan RuszAbstract:High electric fields that occur in thunderstorm clouds in the Earth’s atmosphere might accelerate energetic charged particles produced by Cosmic Rays. Such energetic particles, especially electrons, can cause additional ionization as they are multiplied and thus form avalanche of relativistic electrons. These relativistic electrons emit Bremsstrahlung in the X- or gamma-ray spectral ranges as they lose their kinetic energy via collisions. Thunderstorm ground enhancements (TGEs) of Secondary Cosmic ray fluxes recorded at the top of a sharp rocky mountain of Lomnický Stit in High Tatras (2634 m, Slovak Republic) are compared with simultaneous measurements of electric field at the mountain top and on its slope at the observatory of Skalnate Pleso (1780 m). Results of measurements performed from May to September in 2017 and from May to October in 2018 are presented. The Cosmic ray flux is measured by Space Environment Viewing and Analysis Network (SEVAN) and by neutron monitor with 1-s resolution. The TGEs that persisted usually several minutes were mainly detected in the SEVAN channel 1 which has the lowest energy threshold, about 7–8 MeV. A statistical analysis shows that these enhancements usually occurred (not only) during large values of vertical, upward-pointing electric fields measured just above the detector. It is shown that the measurement of electric field at Skalnate Pleso, distant about 1.86 km from the mountain top is also partly correlated with the enhancements and can provide additional useful information about the distance or dimension of charge structure and dynamics of electric field, especially on short time scales. The enhancements usually did not exceed several tens of percent of background values. However, events that exceeded the background values several times were also recorded. The most extreme event exceeded the background values about 215 times. This event was also detected by other SEVAN channels and by the neutron monitor (~ 130% enhancement), which indicates a possibility of photonuclear reactions. The enhancements were often terminated by a nearby lightning.
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correlations between Secondary Cosmic ray rates and strong electric fields at lomnický stit
Journal of Geophysical Research, 2017Co-Authors: K. Kudela, Jaroslav Chum, M Kollarik, R Langer, I Strharský, J BaseAbstract:Since March 2014, there is a continuous measurement of Secondary Cosmic Rays by the detector system SEVAN (Space Environmental Viewing and Analysis Network) at Lomnický stit, altitude 2,634 m above sea level. Starting from June 2016, the count rates (1 s resolution) obtained from the three SEVAN detectors and from their coincidences are available, along with selected meteorological characteristics. Since 30 May 2016 the electric field measurements have been installed at the same site. Several events with clear increase of the count rate in the upper detector of SEVAN were observed during the thunderstorms until 17 September 2016. Examples of these measurements are presented and discussed. Barometric pressure correction and elimination of low-frequency variability from the signal allow to extract 2 min averaged increases from the data. It is shown that the 2 min averaged increases of count rates measured by SEVAN correspond with periods of high electric field (with higher probability during negative polarity) rather than with the individual discharges (lightning).