arXiv subjects

A. Vacchi

Publications and source records attributed to A. Vacchi.

99 records · Page 6Linked to original sources

arXiv2005

Beam test results of the irradiated Silicon Drift Detector for ALICE

The Silicon Drift Detectors will equip two of the six cylindrical layers of high precision position sensitive detectors in the ITS of the ALICE experiment at LHC. In this paper we report the beam test results of a SDD irradiated with 1 GeV electrons. The aim of this test was to verify the radiation tolerance of the device under an electron fluence equivalent to twice particle fluence expected during 10 years of ALICE operation.

physics.ins-det↗

arXiv2002

The Cosmic-Ray Proton and Helium Spectra measured with the CAPRICE98 balloon experiment

A new measurement of the primary cosmic-ray proton and helium fluxes from 3 to 350 GeV was carried out by the balloon-borne CAPRICE experiment in 1998. This experimental setup combines different detector techniques and has excellent particle discrimination capabilities allowing clear particle identification. Our experiment has the capability to determine accurately detector selection efficiencies and systematic errors associated with them. Furthermore, it can check for the first time the energy determined by the magnet spectrometer by using the Cherenkov angle measured by the RICH detector well above 20 GeV/n. The analysis of the primary proton and helium components is described here and the results are compared with other recent measurements using other magnet spectrometers. The observed energy spectra at the top of the atmosphere can be represented by (1.27+-0.09)x10^4 E^(-2.75+-0.02) particles (m^2 GeV sr s)^-1, where E is the kinetic energy, for protons between 20 and 350 GeV and (4.8+-0.8)x10^2 E^(-2.67+-0.06) particles (m^2 GeV nucleon^-1 sr s)^-1, where E is the kinetic energy per nucleon, for helium nuclei between 15 and 150 GeV nucleon^-1.

astro-ph↗

arXiv2001

Physics with Low-Energy Muons at a Neutrino Factory Complex

The physics potential of an intense source of low-energy muons is studied. Such a source is a necessary stage towards building the neutrino factories and muon colliders which are being considered at present. The CERN Neutrino Factory could deliver muon beams with intensities 3-4 orders of magnitude higher than available now, with large freedom in the choice of the time structure. Low-energy muon physics contributes to many fields of basic research, including rare muon decays, i.e., decays that do not conserve muon number, measurements of fundamental constants, the muon anomalous magnetic moment, determination of the Lorentz structure of the weak interaction, QED tests, CPT tests, proton and nuclear charge distributions (even for short-lived isotopes), and condensed matter physics. In studying the experimental programme, we analyse the present limitations, list the requirements on the new muon beams, and describe some ideas on how to implement these beam lines in a CERN neutrino factory complex.

hep-ph↗

arXiv2001

A High Granularity Imaging Calorimeter for Cosmic-Ray Physics

An imaging calorimeter has been designed and is being built for the PAMELA satellite-borne experiment. The physics goals of the experiment are the measurement of the flux of antiprotons, positrons and light isotopes in the cosmic radiation. The calorimeter is designed to perform a precise measurement of the total energy deposited, to reconstruct the spatial development of the showers (both in the longitudinal and in the transverse directions), and to measure the energy distribution along the shower itself. From this information, the calorimeter will identify antiprotons from a electron background and positrons in a background of protons with an efficiency of about 95% and a rejection power better than 10^-4. Furthermore, a self-trigger system has been implemented with the calorimeter that will be employed to measure high-energy (from about 300 GeV to more than 1 TeV) electrons. The instrument is composed of 22 layers of tungsten, each sandwiched between two "views" of silicon strip detectors (X and Y). The signals are read out by a custom VLSI front-end chip, the CR1.4P, specifically designed for the PAMELA calorimeter, with a dynamic range of 7.14 pC or 1400 mip (minimum ionizing particle). We report on the simulated performance and prototype design.

physics.ins-det↗

arXiv2001

In-flight performances of SilEye-2 Experiment and cosmic ray abundances inside space station Mir

Cosmic ray measurements performed with the instrument SilEye-2 on Mir space station are presented. SilEye-2 is a silicon detector telescope for the study of the causes of Light Flashes perception by astronauts. As a stand-alone device, it monitors in the short and long term the radiation composition inside Mir. The cosmic ray detector consists of an array of 6 active silicon strip detectors which allow nuclear identification of cosmic rays up to Iron. The device was operational for more than 1000 hours in the years 1998-2000, measuring also several Solar Particle Events. In this work we present the in-flight performance of the instrument and nuclear abundance data from Boron to Silicon above ~150 MeV/n inside Mir.

astro-ph↗

arXiv2001

Light Isotope Abundances in Solar Energetic Particles measured by the Space Instrument NINA

This article reports nine Solar Energetic Particle events detected by the instrument NINA between October 1998 and April 1999. NINA is a silicon-based particle detector mounted on-board the Russian satellite Resurs-01-N4, which has flown at an altitude of about 800 km in polar inclination since July 1998. For every solar event the power-law He4 spectrum across the energy interval 10--50 MeV/n was reconstructed, and spectral indexes, gamma, from 1.8 to 6.8 extracted. Data of He3 and He4 were used to determine the He3/He4 ratio, that for some SEP events indicated an enrichment in He3. For the 1998 November 7 event the ratio reached a maximum value of 0.33+- 0.06, with spectral indexes of gamma = 2.5 +- 0.6 and gamma = 3.7 +- 0.3 for He3 and He4, respectively. The He3/He4 ratio averaged over the remaining events was 0.011 +- 0.004. For all events the deuterium-to-proton ratio was determined. The average value over all events was (3.9+-1.4) 10^{-5} across the energy interval 9--12 MeV/n. For one event (1998 November 24) this ratio yielded approximately 10 times higher than normal coronal values. Upper limits on the H3/H1 counting ratio for all events were determined. For the 1998 November 14 SEP event the high flux of heavy particles detected made it possible to reconstruct the carbon and oxygen flux.

astro-ph↗

arXiv2000

In-Orbit Performance of the Space Telescope NINA and GCR Flux Measurements

The NINA apparatus, on board the Russian satellite Resurs-01 n.4, has been in polar orbit since 1998 July 10, at an altitude of 840 km. Its main scientific task is to study the galactic, solar and anomalous components of cosmic rays in the energy interval 10--200 MeV/n. In this paper we present a description of the instrument and its basic operating modes. Measurements of Galactic Cosmic Ray spectra will also be shown.

astro-ph↗

arXiv1999

The AGILE gamma-ray detector

The gamma-ray detector AGILE, operating in the energy range from 30 MeV to 50 GeV, is composed by a tracking part, a light calorimeter and an anticoincidence system. Here we describe the detector and its capabilities to determine the arrival direction and energy of the detected photons.

astro-ph↗

arXiv1998

AGILE: a Gamma-Ray Mission for a Light Imaging Detector

AGILE is an innovative, cost-effective gamma-ray mission proposed to the ASI Program of Small Scientific Missions. It is planned to detect gamma-rays in the 30 MeV - 50 GeV energy band and operate as an {\bf Observatory} open to the international community. Primary scientific goals include the study of AGNs, gamma-ray bursts, Galactic sources, unidentified gamma-ray sources, solar flares, and diffuse gamma-ray emission. AGILE is planned to be operational during the year 2001 for a 3-year mission. It will ideally `fill the gap' between EGRET and GLAST, and support ground-based multiwavelength studies of high-energy sources.

astro-ph↗