Carbon Nanotubes-Based Radiation Detectors

Communications engineering / telecommunication

Ultrahigh Energy Cosmic Rays Detection

The paper describes methods used for the detection of cosmic rays with energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3 10^19 eV induced by their interaction with the 2.7 K primordial photons. This has become known as the GZK cutoff. However, several showers have been detected with estimated primary energy exceeding this limit.Comment: 4 pages, 4 figures. To appear in the proceedings of 17th Conference on High Energy Physics (IFAE 2005) (In Italian), Catania, Italy, 30 Mar - 2 Apr 200

The ARCADE Raman Lidar System for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is the next generation of ground-based very high energy gamma-ray instruments; the facility will be organized in two arrays, one for each hemisphere. The atmospheric calibration of the CTA telescopes is a critical task. The atmosphere affects the measured Cherenkov yield in several ways: the air-shower development itself, the variation of the Cherenkov angle with altitude, the loss of photons due to scattering and absorption of Cherenkov light out of the camera field-of-view and the scattering of photons into the camera. In this scenario, aerosols are the most variable atmospheric component in time and space and therefore need a continuous monitoring. Lidars are among the most used instruments in atmospheric physics to measure the aerosol attenuation profiles of light. The ARCADE Lidar system is a very compact and portable Raman Lidar system that has been built within the FIRB 2010 grant and is currently taking data in Lamar, Colorado. The ARCADE Lidar is proposed to operate at the CTA sites with the goal of making a first survey of the aerosol conditions of the selected site and to use it as a calibrated benchmark for the other Lidars that will be installed on site. It is proposed for CTA that the ARCADE Lidar will be first upgraded in Italy and then tested in parallel to a Lidar of the EARLINET network in L'Aquila. Upgrades include the addition of the water vapour Raman channel to the receiver and the use of new and better performing electronics. It is proposed that the upgraded system will travel to and characterize both CTA sites, starting from the first selected site in 2016

Go to the astroparticle physics school with the Toledo Metro Station Totem-Telescope for cosmic rays

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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

MoO3 films grown on polycrystalline Cu: Morphological, structural, and electronic properties

In this work, the authors investigated MoO3 films with thickness between 30 nm and 1 μm grown at room temperature by solid phase deposition on polycrystalline Cu substrates. Atomic force microscopy, scanning electron microscopy, and scanning tunneling microscopy revealed the presence of a homogenous MoO3 film with a "grainlike" morphology, while Raman spectroscopy showed an amorphous character of the film. Nanoindentation measurements evidenced a coating hardness and stiffness comparable with the copper substrate ones, while Auger electron spectroscopy, x-ray absorption spectroscopy, and secondary electron spectroscopy displayed a pure MoO3 stoichiometry and a work function Φ MoO3 = 6.5 eV, 1.8 eV higher than that of the Cu substrate. MoO3 films of thickness between 30 and 300 nm evidenced a metallic behavior, whereas for higher thickness, the resistance-temperature curves showed a semiconducting character

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO