Abstract
The 3×1×1 m
3
demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to ...provide precise timing capabilities. The performance of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.
A neurologic deficit of sudden onset conforming to a vascular territory is a clear clinical indication that a patient suffers from an acute stroke. However, the imagistic diagnostic confirmation is ...not always readily available. We are now able to offer comprehensive medical support for the patient after an acute stroke and to make a prodigious rehabilitation program after the damage is done, but this is not offering the chance for improvement. An opportunity to better diagnose ischemic stroke seems to be available by using neuronal biomarkers. Extensive research is being conducted in this field and useful information is beginning to gather. This mini-review aims to highlight selected studies that appear to be of particular interest for the clinical neurologist. The most promising biomarkers (or rather panels of biomarkers) are presented with theirs clinical usefulness and limitations.
Radio emission from particle showers can be used as a method of neutrino detection in the high and very high energy range as a Cherenkov pulse originates from the charge excess developing in the ...medium. Our study presents simulations of neutrino induced showers in rock salt and the radio emission that they generate, using the HERWIG, GEANT4 and AIRES codes. We have performed a complete study of all neutrino flavours interacting on nuclei, both for charged-current and neutral-current interactions, using the knowledge and codes available today. As primary neutrino energies we have chosen three values: 1012eV, 1015eV and 1017eV. We have injected all the particles resulting from the first interactions into shower simulation codes.
Salt is one of the dielectric media proposed for radio detection of neutrinos already in the sixties of last century, and can be found in large volumes throughout the world.
The calculation of the radio signal was performed considering the entire shower evolution, by approximating the shower with a current density. We have taken into account, in the equations, only the longitudinal profile. The aim of this study is to investigate whether different interactions can be discriminated in an experiment for detection of high energy particles based on the radio emission from the showers they initiate in a dense medium. For this we have performed and systematically analyzed simulations from several points of view.
We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 × 1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the ...estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 × 1019 eV. The principal conclusions are (1) The flattening of the spectrum near 5 × 1018 eV, the so-called "ankle," is confirmed. (2) The steepening of the spectrum at around 5 × 1019 eV is confirmed. (3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index γ of the particle flux ( ∝ E−γ ) changes from 2.51 ± 0.03 ( stat ) ± 0.05 ( syst ) to 3.05 ± 0.05 ( stat ) ± 0.10 ( syst ) before changing sharply to 5.1 ± 0.3 ( stat ) ± 0.1 ( syst ) above 5 × 1019 eV. (4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8 × 1018 eV.
We report a measurement of the energy spectrum of cosmic rays above 2.5 × 1018 eV based on 215 030 events. New results are presented: at about 1.3 × 1019 eV , the spectral index changes from 2.51 ± ...0.03 (stat) ± 0.05 (syst) to 3.05 ± 0.05 (stat) ± 0.10 (syst), evolving to 5.1 ± 0.3 (stat) ± 0.1 (syst) beyond 5 × 1019 eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5 × 1018 eV is 5.66 ± 0.03 (stat) ± 1.40 (syst) × 1053 erg Mpc−3.
Precise measurements of the muon flux are important for different practical applications, in environmental studies and for the estimation of the water equivalent depths of underground sites. A first ...configuration of the mobile detector was composed of two 1 m2 scintillator plates, each viewed by wave length shifters and read out by two PMTs (Photomultiplier Tubes). A more recent configuration of the mobile muon detectors, set up in IFIN-HH, Romania, consists of two 1 m2 detection layers, each one including four 1×0.25 m2 large scintillator plates. The light output in each plate is collected by twelve optical fibers and then read out by one PMT. The calibration has been made by comparing the energy deposit spectrum of minimum ionizing particles with the spectra simulated with the GEANT4 code. The device is used to measure the muon flux on different locations at the surface and underground.
Precise measurements of the muon flux are important for different practical applications, both in environmental studies and for the estimation of the water equivalent depths of underground sites. A ...mobile detector for cosmic muon flux measurements has been set up at IFIN-HH, Romania. The device is used to measure the muon flux on different locations at the surface and underground. Its first configuration, not used in the present, has been composed of two 1 m2 scintillator plates, each viewed by wave length shifters and read out by two Photomultiplier Tubes (PMTs). A more recent configuration, consists of two 1 m2 detection layers, each one including four 1 · 0,25 m2 large scintillator plates. The light output in each plate is collected by twelve optical fibers and then read out by one PMT. Comparative results were obtained with both configurations.
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