795 research outputs found
Precise determination of muon and electromagnetic shower contents from shower universality property
We consider two new aspects of Extensive Air Shower development universality
allowing to make accurate estimation of muon and electromagnetic (EM) shower
contents in two independent ways. In the first case, to get muon (or EM) signal
in water Cherenkov tanks or in scintillator detectors it is enough to know the
vertical depth of shower maximum and the total signal in the ground detector.
In the second case, the EM signal can be calculated from the primary particle
energy and the zenith angle. In both cases the parametrizations of muon and EM
signals are almost independent on primary particle nature, energy and zenith
angle. Implications of the considered properties for mass composition and
hadronic interaction studies are briefly discussed. The present study is
performed on 28000 of proton, oxygen and iron showers, generated with CORSIKA
6.735 for spectrum in the energy range log(E/eV)=18.5-20.0 and
uniformly distributed in cos^2(theta) in zenith angle interval theta=0-65
degrees for QGSJET II/Fluka interaction models.Comment: Submitted to Phys. Rev.
The analog signal processing board for the HEAT telescopes
Abstract The aim of the Pierre Auger Observatory is to measure with high statistics the flux, the arrival directions and the mass composition of cosmic rays at the highest energies. Since 2009, the Auger Collaboration has added three new High Elevation Auger Telescopes (HEAT) along with a new 25 km 2 infill array in the field of view of the new telescopes. These enhancements have lowered the energy threshold of the Observatory by about an order of magnitude. In combination with the existing telescopes in Coihueco the vertical field of view is extended to about 60°, allowing the measurement of nearby air showers arising from primaries with energies as low as 2×10 17 eV. In this paper we describe the new front-end analog board developed to process the signals generated by the photomultipliers of the HEAT telescopes. Eighty analog boards have been produced, fully characterized and tested. The main characteristics of the electronic circuits and the circuit parameters are illustrated
The arcade project
The Atmospheric Research for Climate and Astroparticle Detection (ARCADE) project aims to a better comprehension of the limits of applicability, systematics and possible enhancements of the typical techniques used for the measurement of the aerosol attenuation profiles of UV light in cosmic rays and gamma rays experiments. Aerosols are indeed the most variable component in the atmosphere on a short time scale, and experiments based on the detection of the UV light in atmosphere need a continuous monitoring of the aerosol stratification to obtain a reliable evaluation of the properties of the primary particles. The ARCADE project is measuring the aerosol attenuation of UV light due to aerosols with multiple techniques and instruments simultaneously on the same air mass. For this purpose, a Raman + elastic Lidar with a laser source at 355 nm has been built and is currently taking data in Lamar, Colorado together with the Atmospheric Monitoring Telescope (AMT) to detect UV light at a distance of 40 km from the Lidar laser source. The system has been installed on site in 2014 and data were taken every month during moonless nights for one year. A full simulation of the AMT system has been developed. The setup and simulation of the system, together with the AMT calibration system and first collected data are shown
Measurement of Aerosols at the Pierre Auger Observatory
The air fluorescence detectors (FDs) of the Pierre Auger Observatory are
vital for the determination of the air shower energy scale. To compensate for
variations in atmospheric conditions that affect the energy measurement, the
Observatory operates an array of monitoring instruments to record hourly
atmospheric conditions across the detector site, an area exceeding 3,000 square
km. This paper presents results from four instruments used to characterize the
aerosol component of the atmosphere: the Central Laser Facility (CLF), which
provides the FDs with calibrated laser shots; the scanning backscatter lidars,
which operate at three FD sites; the Aerosol Phase Function monitors (APFs),
which measure the aerosol scattering cross section at two FD locations; and the
Horizontal Attenuation Monitor (HAM), which measures the wavelength dependence
of aerosol attenuation.Comment: Contribution to the 30th International Cosmic Ray Conference, Merida
Mexico, July 2007; 4 pages, 4 figure
Neutral N^C^N terdentate luminescent Pt(ii) complexes: their synthesis, photophysical properties, and bio-imaging applications
An emerging field regarding N^C^N terdentate Pt(II) complexes is their application as luminescent labels for bio-imaging. In fact, phosphorescent Pt complexes possess many advantages such as a wide emission color tunability, a better stability towards photo- and chemical degradation, a very large Stokes shift, and long-lived luminescent excited states with lifetimes typically two to three orders of magnitude longer than those of classic organic fluorophores. Here, we describe the synthesis and photophysical characterization of three new neutral N^C^N terdentate cyclometallated Pt complexes as long-lived bio-imaging probes. The novel molecular probes bear hydrophilic (oligo-)ethyleneglycol chains of various lengths to increase their water solubility and bio-compatibility and to impart amphiphilic nature to the molecules. The complexes are characterized by a high cell permeability and a low cytotoxicity, with an internalization kinetics that depends on both the length of the ethyleneglycol chain and the ancillary ligand
Novel N^C^N-cyclometallated platinum complexes with acetylide co-ligands as efficient phosphors for OLEDs
Two new cyclometallated platinum(ii) complexes have been prepared that incorporate a terdentate N^C^N-coordinating ligand and a monodentate acetylide co-ligand. The complexes, namely [PtL 3-CC-C 6H 3F 2] and [PtL 6-CC-C 6H 3F 2] (where HL 3 = 5-methyl-1,3-di(2-pyridyl) benzene; HL 6 = 5-mesityl-1,3-di(2-pyridyl)benzene; H-CC-C 6H 3F 2 = 3,5-difluorophenylacetylene), were prepared by ligand metathesis from the corresponding chloro complex PtL nCl. Both of the new complexes are intensely luminescent in solution, displaying quantum yields superior to PtL nCl. OLEDs have been prepared using the new compounds as phosphorescent emitters. Although both lead to efficient devices, the best electroluminescence quantum efficiencies are obtained with the derivative of HL 6, having the mesityl group on the cyclometallated phenyl ring. The superior performance with this complex can be rationalised in terms of the greater steric hindrance that serves to reduce aggregate-induced quenching
INFN Camera demonstrator for the Cherenkov Telescope Array
The Cherenkov Telescope Array is a world-wide project for a new generation of
ground-based Cherenkov telescopes of the Imaging class with the aim of
exploring the highest energy region of the electromagnetic spectrum. With two
planned arrays, one for each hemisphere, it will guarantee a good sky coverage
in the energy range from a few tens of GeV to hundreds of TeV, with improved
angular resolution and a sensitivity in the TeV energy region better by one
order of magnitude than the currently operating arrays. In order to cover this
wide energy range, three different telescope types are envisaged, with
different mirror sizes and focal plane features. In particular, for the highest
energies a possible design is a dual-mirror Schwarzschild-Couder optical
scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based
camera is being proposed as a solution to match the dimensions of the pixel
(angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made
by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the
focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near
UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a
Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer,
self-trigger and on-demand digitization capabilities specifically developed for
this purpose. The pixel dimensions of mm lead to a very compact
design with challenging problems of thermal dissipation. A modular structure,
made by copper frames hosting one PSM and the corresponding FEE, has been
conceived, with a water cooling system to keep the required working
temperature. The actual design, the adopted technical solutions and the
achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
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