Interplay between scintillation and ionization in liquid xenon Dark Matter searches     

Fedor Bezrukov  Felix Kahlhoefer  Manfred Lindner 《Astroparticle Physics》2011,35(3):119-127

We provide a new way of constraining the relative scintillation efficiency L_eff for liquid xenon. Using a simple estimate for the electronic and nuclear stopping powers together with an analysis of recombination processes we predict both the ionization and the scintillation yields. Using presently available data for the ionization yield, we can use the correlation between these two quantities to constrain L_eff from below. Moreover, we argue that more reliable data on the ionization yield would allow to verify our assumptions on the atomic cross sections and to predict the value of L_eff. We conclude that the relative scintillation efficiency should not decrease at low nuclear recoil energies, which has important consequences for the robustness of exclusion limits for low WIMP masses in liquid xenon Dark Matter searches.  相似文献   

Mineralogy of the lower mantle: A review of ‘super-deep’ mineral inclusions in diamond     

Felix Kaminsky 《Earth》2012,110(1-4):127-147

Starting from the late 1980s, several groups of lower-mantle mineral inclusions in diamond have been found. Three associations were established among them: juvenile ultramafic, analogous to eclogitic, and carbonatitic. The juvenile ultramafic association strongly predominates, and it is composed of ferropericlase, MgSi-, CaSi- and CaTi-perovskites, stishovite, tetragonal almandine-pyrope phase (TAPP), and some others. The association analogous to the upper-mantle eclogitic association, formed from subducting lithosphere, comprises: majorite, CaSi-perovskite bearing compositional Eu anomalies, phase ‘Egg’ with a tetragonal structure, and stishovite. The carbonatitic association is represented by various carbonates, halides, and associated minerals. Some mineral associations (wüstite + periclase and native iron + iron carbides) are, possibly, related to the D″ layer at the core/mantle boundary. The mineralogical composition of the lower mantle is now understood to be more complex than had been suggested in theoretic and experimental works. The proportion of ferropericlase in the lower mantle is higher than it was suggested before, and its composition is more iron-rich (mg = 0.36–0.90) as compared to experimental and theoretical data. Free silica (stishovite) is always present in lower-mantle associations, and a separate aluminous phase (TAPP) has been identified in several areas. These discrepancies suggest that the composition of the lower mantle differs to that of the upper-mantle, and experiments based solely on ‘pyrolitic’ compositions are not, therefore, applicable to the lower mantle. These data indicate a probability of an alternative to the CI-chondrite model of the Earth's formation, for example, an enstatite-chondrite model.  相似文献   

Numerical simulation of waves in the Caspian Sea: calibration and verification of the observation-based source terms     

Alipour  Atefeh  Siadatmousavi  Seyed Mostafa  Jose  Felix 《Ocean Dynamics》2021,71(6-7):699-714

Ocean Dynamics - Third-generation models employ a host of parameterization schemes to consider the input wind forcing and the wave energy dissipation under different physical settings and...  相似文献   

Slowness and azimuth determination for Bucovina array (BURAR) applying multiple signal techniques     

Felix Borleanu  Mihaela Popa  Mircea Radulian  Johannes Schweitzer 《Journal of Seismology》2011,15(3):431-442

The BURAR seismic array, located in Northern Romania (Bucovina region), is designed to monitor events located in an area poorly covered by other existing seismic stations. In order to use the BURAR array for single-station locations, it is crucial to calibrate the azimuth and slowness parameters, which are currently used in array techniques to locate earthquakes, blasts or nuclear explosions. The goal of this study is to apply “f–k” and plane wave fit techniques in order to constrain the slowness and azimuth parameters at BURAR for teleseismic, regional and local events. The analysis was carried out using P and S waves recorded for events occurred between 2004 and 2008 within a radius of 50° around BURAR. The azimuth values obtained applying both methods strongly deviated from the theoretical values for regions like Central Turkey, Bulgaria, Dodecanese Islands and other parts of Greece, while the ray parameter deviations with respect to a 1-D IASP91 reference model are less significant. For the local events, the anomalies are smaller, except the particular case of Vrancea intermediate-depth earthquakes for which strong azimuth deviations (33.5°), both positive and negative, are observed. We investigate how these systematic deviations in azimuth are explained by the structure lateral heterogeneities which characterize the study region.  相似文献   

Mixed-phase clouds cause climate model biases in Arctic wintertime temperature inversions     

Felix Pithan  Brian Medeiros  Thorsten Mauritsen 《Climate Dynamics》2014,43(1-2):289-303

Temperature inversions are a common feature of the Arctic wintertime boundary layer. They have important impacts on both radiative and turbulent heat fluxes and partly determine local climate-change feedbacks. Understanding the spread in inversion strength modelled by current global climate models is therefore an important step in better understanding Arctic climate and its present and future changes. Here, we show how the formation of Arctic air masses leads to the emergence of a cloudy and a clear state of the Arctic winter boundary layer. In the cloudy state, cloud liquid water is present, little to no surface radiative cooling occurs and inversions are elevated and relatively weak, whereas surface radiative cooling leads to strong surface-based temperature inversions in the clear state. Comparing model output to observations, we find that most climate models lack a realistic representation of the cloudy state. An idealised single-column model experiment of the formation of Arctic air reveals that this bias is linked to inadequate mixed-phase cloud microphysics, whereas turbulent and conductive heat fluxes control the strength of inversions within the clear state.  相似文献   

Characterization of indoor and outdoor atmospheric pollutants impacting architectural monuments: the case of San Jerónimo Monastery (Granada, Spain)   总被引：1，自引：1，他引：0  

Velichka Kontozova-Deutsch  Carolina Cardell  Maja Urosevic  Encarnación Ruiz-Agudo  Felix Deutsch  René Van Grieken 《Environmental Earth Sciences》2011,63(7-8):1433-1445

Indoor and outdoor concentrations of atmospheric gaseous pollutants as well as composition, size, and morphology of particulate matter have been investigated at the monastery of San Jerónimo in Granada (Southern Spain). Complementary micro- and nano-analytical techniques were applied; elemental and mineralogical composition and morphological characteristics of particulate matter were investigated combining electron probe microanalysis at the single particle level, and bulk aerosol samples were analyzed using energy-dispersive X-ray fluorescence, X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analyzer and transmission electron microscopy (TEM). Microclimatic conditions at the monastery were monitored, and gas concentrations were assessed by means of diffusion tubes subsequently analyzed with ion chromatography. Results revealed high abundances of soil dust particles (aluminosilicates, calcite, dolomite, quartz), salt aerosols (chlorides, sulfates and ammonium-rich salts), and NO₂ and SO₂ both outdoors and indoors. Amorphous black carbon particles had surprisingly high abundances for Granada, a non-industrialized city. The composition of indoor particles corresponds to severe weathering affecting the construction materials and artworks inside the church; moreover their composition promotes a feedback process that intensifies the deterioration. Chemical reactions between chloride-rich salts and pigments from paintings were confirmed by TEM analyses. Indoors, blackening of surface decorative materials is fostered by particle re-suspension due to cleaning habits in the monastery (i.e. dusting). This is the first air quality study performed in a monument in the city of Granada with the aim of developing a strategy for preventive conservation.  相似文献   

Galactic winds and the Lyα forest     

Vincent Desjacques  Adi Nusser  Martin G. Haehnelt  Felix Stoehr 《Monthly notices of the Royal Astronomical Society》2004,350(3):879-892

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Erwiderung     

F. Felix Hahn 《International Journal of Earth Sciences》1914,5(4):320-320

Ohne Zusammenfassung  相似文献   

Gamma ray signatures of ultra high energy cosmic ray accelerators: electromagnetic cascade versus synchrotron radiation of secondary electrons     

Stefano Gabici  Felix A. Aharonian 《Astrophysics and Space Science》2007,309(1-4):465-469

We discuss the possibility of observing ultra high energy cosmic ray sources in high energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background photons. These electrons start an electromagnetic cascade that results in a broad band gamma ray emission. We show that in a magnetized Universe (B≳10⁻¹² G) such emission is likely to be too extended to be detected above the diffuse background. A more promising possibility comes from the detection of synchrotron photons from the extremely energetic secondary electrons. Although this emission is produced in a rather extended region of size ∼10 Mpc, it is expected to be point-like and detectable at GeV energies if the intergalactic magnetic field is at the nanogauss level.   相似文献   

The distance to SS 433/W50 and its interaction with the interstellar medium     

Felix J. Lockman  Katherine M. Blundell  W. M. Goss 《Monthly notices of the Royal Astronomical Society》2007,381(3):881-893

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