|
|
M. T. Pazianotto, M. A. Cortés-Giraldo, C. A. Federico, G. Hubert, O. L. Gonçalez, J. M. Quesada, B. V. Carlson. (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. ϕ time series (Vol. 60).
Abstract: The level of solar modulation at different times (related to the solar activity) is a central question of solar and galactic cosmic-ray physics. In the first paper of this series, we have established a correspondence between the uncertainties on ground-based detectors count rates and the parameter ϕ (modulation level in the force-field approximation) reconstructed from these count rates. In this second paper, we detail a procedure to obtain a reference ϕ time series from neutron monitor data. We show that we can have an unbiased and accurate ϕ reconstruction (Δϕ/ϕ≃10%). We also discuss the potential of Bonner spheres spectrometers and muon detectors to provide ϕ time series. Two by-products of this calculation are updated ϕ values for the cosmic-ray database and a web interface to retrieve and plot ϕ from the 50’s to today (http://lpsc.in2p3.fr/crdb).
Keywords: Cosmic rays Muon detector Neutron monitor Solar modulation
Programme: 1112
|
|
|
|
A. C. M. Prado, M. T. Pazianotto, O. L. Gonçalez, L. R. dos Santos, A. D. Caldeira, H. H. C. Pereira, G. Hubert, C. A. Federico. (2017). Investigation of the influence of the position inside a small aircraft on the cosmic-radiation-induced dose (Vol. 176).
Abstract: Abstract. This article report the measurements on-board a small aircraft at the same altitude and around the same geographic coordinates. The measurements of A
Programme: 1112
|
|
|
|
.
|
|
|
|
G. Hubert, P. Ricaud. (2019). Four Years of Measurements of the Energy Spectrum of Cosmic-Ray-induced-neutrons on the Concordia Antarctic Station Taking into Account Environmental and Systematic Effects.
|
|
|
|
Hubert, S. Aubry. (2016). Seasonal Variations of Cosmic-Ray-Induced Atmospheric Neutron at High-Altitude in Medium Geomagnetic Latitude and Antarctica Environment.
|
|
|
|
Maxime Pineaux, Thomas Merkling, Etienne Danchin, Scott Hatch, David Duneau, Pierrick Blanchard, Sarah Leclaire. (2020). Sex and hatching order modulate the association between MHC-II diversity and fitness in early-life stages of a wild seabird (Vol. 29).
Abstract: Genes of the major histocompatibility complex (MHC) play a pivotal role in parasite resistance, and their allelic diversity has been associated with fitness variations in several taxa. However, studies report inconsistencies in the direction of this association, with either positive, quadratic or no association being described. These discrepancies may arise because the fitness costs and benefits of MHC diversity differ among individuals depending on their exposure and immune responses to parasites. Here, we investigated in black-legged kittiwake (Rissa tridactyla) chicks whether associations between MHC class-II diversity and fitness vary with sex and hatching order. MHC-II diversity was positively associated with growth and tick clearance in female chicks, but not in male chicks. Our data also revealed a positive association between MHC-II diversity and survival in second-hatched female chicks (two eggs being the typical clutch size). These findings may result from condition-dependent parasite infections differentially impacting sexes in relation to hatching order. We thus suggest that it may be important to account for individual heterogeneities in traits that potentially exert selective pressures on MHC diversity in order to properly predict MHC–fitness associations.
Keywords: divergent allele advantage fitness heterozygote advantage immunity Ixodes uriae parasite-mediated selection
Programme: 1162
|
|
|
|
Barbora Chattová, Marc Lebouvier, Myriam De Haan, Bart Van de Vijver. (2017). The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species.
Abstract: Five species of the terrestrial diatom genus Luticola D.G.Mann were found during a taxonomic survey of two small volcanic islands, Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean). Apart from the two already known Luticola species L. beyensii Van de Vijver et al. and L. subcrozetensis Van de Vijver et al., two new species are described: L. ivetana Chattová & Van de Vijver sp. nov. and L. vancampiana Chattová & Van de Vijver sp. nov. Finally, one, up to now unknown, Luticola species is briefly discussed and illustrated. Detailed morphological descriptions of these taxa are provided based on both light and scanning electron microscopy observations. Morphological features of the new species are compared to morphologically similar taxa, and notes on their ecology and biogeography are added.
Keywords: Bacillariophyta diatoms Luticola morphology new species
Programme: 136
|
|
|
|
Guillaume Hubert, Sébastien Aubry. (2018). Analysis of Exposure to Solar and Galactic Cosmic Radiations of Flights Representative of the European International Air Traffic (Vol. 190).
Abstract: This study analyzed the impact of galactic and solar cosmic rays on ambient dose equivalent during airline travel. A high statistic of flights are considered, which is representative of European international air traffic. Flight paths are based on the Eurocontrol Demand Data Repository and consider realistic flight plans with and without regulations or updated with radar data from the Central Flow Management Unit. Ambient dose equivalent during flights was investigated during quiet solar periods and extreme solar flare events. Thus, the statistical analyses presented here take into account route characteristics (departure, arrival, continent, etc.) and space weather conditions. The findings of this work show the important influence of flight path, particularly the latitude, which drives the cutoff rigidity variations. Moreover, dose values vary drastically during ground level enhancement events, with the route path (latitude, longitude and altitude) and the phasing of the solar event. This study highlights the importance of monitoring these solar events and developing a physical approach to obtain reliable assessment of ambient dose equivalents.
Programme: 1112
|
|
|
|
P. Li Cavoli, G. Hubert, J. Busto. (2017). Study of atmospheric muon interactions in Si nanoscale devices (Vol. 12).
Abstract: In this paper the impact of the muon radial ionization profile on Single-Event Upset (SEU) sensitivity for nanoscale technologies is investigated with simulations and experimental measurements. The physical model used in the simulation framework is compared with experimental measurements of the charge deposit induced by atmospheric particles on a CCD pixel array. This scientific instrument is used to monitor the atmospheric muons, and allows to investigate the charge deposition induced by muon of micrometric sensitive volumes (i.e. the CCD pixel). Atmospheric and underground sites are considered for monitoring pixel-charge events and the combined analysis of the data is used to discriminate muons from other particles. 3D descriptions of muon tracks were simulated with radiation transport code Geant4, and coupled with Single Event Effect (SEE) simulation based on multi-physics approaches (MUSCA SEP3) to investigate the SEU cross-section and Soft Error Rate (SER) trends as function of technological downscaling. SER trends are analyzed for bulk technologies, from 65 to 14 nm integration nodes, in both ground and avionic environments. Results show that for technologies whose characteristic lengths are greater than 50 nm, it is not necessary to consider radial energy deposit structure of muon in SEE assessment. At ground, downscaling of the technological node induces an increase in the SEU susceptibility to cosmic ray showers, mainly because of muons. For nanoscale devices operating at avionic altitude, the muon contribution to the SER is very weak in comparison of the proton and neutron contributions.
Programme: 1112
|
|
