|
Hennion F., Labarrere B., Chesneau E. & Prinzing A. . (2016). Metabolites relating to phenotypes and environments: between-population differentiation within species. .
|
|
Hennion F., Dorey T., Rantier Y., Tarayre M. . (2017). Lyallia kerguelensis, a Kerguelen endemic cushion plant from extreme environments in the face of climate change. .
|
|
Laforge M., Colas B., Hennion F., Normand V., Robert T., Nadot S. . (2017). A glimpse into the reproductive biology of buttercups in the Kerguelen Islands..
|
G. Hubert. (2017). Ground Albedo Neutron Impacts to Seasonal Variations of Cosmic-Ray-Induced Neutron in Medium Geomagnetic Latitude and Antarctica: Impacts on Soft Error Rate (Vol. 64).
Abstract: This paper investigates the impact of ground albedo neutrons in the terrestrial radiation field and their seasonal variations. A modeling methodology is proposed, it is based on ATMORAD (atmospheric shower modeling) and GEANT4 simulations taking into account the soil characteristics and hydrogen content. This method was validated thanks to neutron measurements performed in two high altitude stations located in medium geomagnetic latitude and Antarctica (Pic-du-Midi and Concordia, respectively). Thus, the chemical rock composition, the density, the water content and the snow pack impacts to neutron spectrum were investigated. Simulated and measured spectra were compared. Analyses show that variations are dominant in the thermal domain (i.e. En <;0.5 eV) and lesser degree in epithermal and evaporation domains (i.e. 0.5 eV <; En <;0.1 MeV and 0.1 MeV <; En <;20 MeV, respectively). The last part investigates the impact induced by the evaporation neutron contribution to Single Event Rate (more impacted by the ground albedo neutron). Results show that evaporation neutrons contribution to the total SER should be assessed for high-sensitive technologies.
Keywords: albedo Antarctica ATMORAD Atmospheric modeling atmospheric shower modeling chemical rock composition Concordia cosmic ray apparatus cosmic ray neutrons cosmic ray showers Cosmic-ray induced neutrons cosmic-ray-induced neutron density epithermal domain evaporation domain evaporation neutron contribution GEANT4 GEANT4 simulations geochemistry ground albedo neutron ground albedo neutron impacts high-altitude stations high-sensitive technologies hydrogen content medium geomagnetic latitude modeling methodology neutron measurements neutron spectrum Neutrons nuclear electronics Pic-du-Midi Protons radiation hardening (electronics) rocks seasonal variations Single Event Rate Snow snow pack soft error rate soil Soil soil characteristics terrestrial radiation field water content
Programme: 1112
|
Hubert G., Pazianotto M. T., Federico C. A. (2017). Modeling of ground albedo neutrons to investigate seasonal cosmic ray?induced neutron variations measured at high?altitude stations (Vol. 121).
Abstract: Abstract This paper investigates seasonal cosmic ray?induced neutron variations measured over a long?term period (from 2011 to 2016) in both the high?altitude stations located in medium geomagnetic latitude and Antarctica (Pic?du?Midi and Concordia, respectively). To reinforce analysis, modeling based on ground albedo neutrons simulations of extensive air showers and the solar modulation potential was performed. Because the local environment is well known and stable over time in Antarctica, data were used to validate the modeling approach. A modeled scene representative to the Pic?du?Midi was simulated with GEANT4 for various hydrogen properties (composition, density, and wet level) and snow thickness. The orders of magnitudes of calculated thermal fluence rates are consistent with measurements obtained during summers and winters. These variations are dominant in the thermal domain (i.e., En??20?MeV) is weakly impacted. The role of hydrogen content on ground albedo neutron generation was investigated with GEANT4 simulations. These investigations focused to mountain environment; nevertheless, they demonstrate the complexity of the local influences on neutron fluence rates.
Keywords: albedo neutron cosmic ray spectrometer
Programme: 1112
|
. (2017). Extensive air shower Monte Carlo modeling at the ground and aircraft flight altitude in the South Atlantic Magnetic Anomaly and comparison with neutron measurements (Vol. 88).
Abstract: Modeling cosmic-ray-induced particle fluxes in the atmosphere is very important for developing many applications in aeronautics, space weather and on ground experimental arrangements. There is a lack of measurements and modeling at flight altitude and on ground in the South Atlantic Magnetic Anomaly. In this work we have developed an application based on the Geant4 toolkit called gPartAt that is aimed at the analysis of extensive air shower particle spectra. Another application has been developed using the MCNPX code with the same approach in order to evaluate the models and nuclear data libraries used in each application. Moreover, measurements were performed to determine the ambient dose equivalent rate of neutrons at flight altitude in different regions and dates in the Brazilian airspace; these results were also compared with the simulations. The results from simulations of the neutron spectra at ground level were also compared to data from a neutron spectrometer in operation since February 2015 at the Pico dos Dias Observatory in Brazil, at 1864m above sea level, as part of a collaboration between the Institute for Advanced Studies (IEAv) and the French Aerospace Lab (ONERA). This measuring station is being operated with support from the National Astrophysics Laboratory (LNA). The modeling approaches were also compared to the AtmoRad computational platform, QARM, EXPACS codes and with measurements of the neutron spectrum taken in 2009 at the Pico dos Dias Observatory.
Keywords: Extensive air shower modeling Flight altitude Geant4 MCNPX Monte Carlo method simulation South Atlantic Magnetic Anomaly
Programme: 1112
|
A. Ghelfi, D. Maurin, A. Cheminet, L. Derome, G. Hubert, F. Melot. (2017). Neutron monitors and muon detectors for solar modulation studies: 2. ? time series (Vol. 60).
Keywords: Cosmic rays Muon detector Neutron monitor Solar modulation
Programme: 1112
|
. (2017). Atmospheric Cosmic-Ray Variation and Ambient Dose Equivalent Assessments Considering Ground Level Enhancement Thanks to Coupled Anisotropic Solar Cosmic Ray and Extensive Air Shower Modeling (Vol. 188).
Abstract: This work investigates the impact of Forbush decrease (FD) and ground-level enhancement (GLE) in the atmosphere, based on solar and galactic cosmic-ray models and the extensive air shower simulations. This approach gives the possibility to investigate both the dynamic behavior of neutron monitors (NM) (using response function) and the flight dose. The ambient dose equivalent during quiet solar activity and solar events (i.e., FDs and GLEs) were investigated for realistic flight plans issued from the Eurocontrol Demand Data Repository. The calculated ambient dose equivalents were compared with flight measurements in quiet solar conditions; comparisons are relevant and demonstrate the ability to estimate the dose level. The GLE model was validated for the GLEs 5 and 69 using the cosmic-ray variation recorded by NMs. The GLE model was applied to flight dose calculations. All of these results show that dose values vary drastically with the route path (latitude, longitude and altitude) and with the delay between the flight departure and the solar event occurrence. Doses induced by extreme GLE events were investigated specifically for London to New York flights, and resulting additional doses are a few hundred or 1,000 ?Sv, impacting significantly the annual effective dose. This highlights the importance of monitoring extreme solar events and using realistic semi-empirical and particle transport methods for reliable calculation of dose levels.
Programme: 1112
|
. (2017). Analysis of the angular distribution of cosmic-ray-induced particles in the atmosphere based on Monte Carlo simulations including the influence of the Earth's magnetic field (Vol. 97).
Abstract: Several applications exist that calculate cosmic-ray-induced particle (CRIP) spectra as a function of the altitude in the atmosphere. In general, the Earth's magnetic field is only used to modulate the primary cosmic radiation that arrives at the top of the atmosphere, but it can also modulate low-energy charged particles at flight altitudes. The effects of the Earth's magnetic field on the angular distributions of CRIP transport in the atmosphere should be quantified, because it furnishes important data for the development of applications for aircrew radiation protection, onboard dosimetry and the simulation of irradiation of sensitive equipment and particle detector systems used at ground level, flight and atmospheric balloon altitudes. In this work we calculate the angular distribution of the cosmic-ray-induced particles (CRIP) for altitudes from ground level up to 80?km using an application based on Geant4 developed in previous works. In order to quantify the effects of the Earth's magnetic field (EMF) on the angular distribution of the CRIP, the calculations were carried out both including the EMF in the South Atlantic Magnetic region and omitting it. A part of these results were compared with analytical calculations of the ratio between the mean free path of the primary particles from the cosmic radiation and the deflection radii at different altitudes in the atmosphere. The albedos of neutrons and protons at 80?km were estimated and compared with the QARM and ATMORAD codes, which ignore the Earth's magnetic field.
Keywords: Angular distribution of the extensive air shower Flight altitude Monte Carlo method simulation South Atlantic Magnetic Anomaly
Programme: 1112
|
|
Philippe Koubbi, Susie Grant, David Ramm, Marino Vacchi, Laura Ghigliotti, Eva Pisano. (2017). Conservation and Management of Antarctic Silverfish Pleuragramma antarctica Populations and Habitats.
|
