M. Boezio

PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics

PAMELA is a satellite-borne experiment designed for precision studies of the charged cosmic radiation. The primary scientific goal is the study of the antimatter component of the cosmic radiation (antiprotons, 80 MeV - 190 GeV; and positrons, 50 MeV - 270 GeV) in order to search for evidence of dark matter particle annihilations. PAMELA will also search for primordial antinuclei (in particular, anti-helium), and test cosmic-ray propagation models through precise measurements of the antiparticle energy spectrum and studies of light nuclei and their isotopes. Concomitant goals include a study of solar physics and solar modulation during the 24th solar minimum by investigating low energy particles in the cosmic radiation; and a reconstruction of the cosmic ray electron energy spectrum up to several TeV thereby allowing a possible contribution from local sources to be studied. PAMELA is housed on-board the Russian Resurs-DKl satellite, which was launched on June 15th 2006 in an elliptical (350-600 km altitude) orbit with an inclination of 70 degrees. PAMELA consists of a permanent magnet spectrometer, to provide rigidity and charge sign information; a Time-of-Flight and trigger system, for velocity and charge determination; a silicon-tungsten calorimeter, for lepton/hadron discrimination; and a neutron detector. An anticoincidence system is used offline to reject false triggers. In this article the PAMELA experiment and its status are reviewed. A preliminary discussion of data recorded in-orbit is also presented.

The PAMELA experiment in space

We provide in this paper a status report of the space experiment PAMELA. PAMELA aims primarily to measure the flux of antiparticles, namely antiprotons and positrons, in cosmic rays with unpreceden ...

WiZard SiW imaging calorimeter: a preliminary study on its particle identification capability during a balloon flight in 1993

Abstract The WiZard Collaboration is engaged in a program to study the antimatter components of the cosmic rays. A silicon-tungsten (Wiue5f8W) imaging calorimeter has been developed as part of this program. We present its performance and preliminary results, obtained during a balloon flight on September 8, 1993. The flight was dedicated to the measurement of the positron spectrum in the energy range 4–50 GeV and took place from Ft. Sumner, New Mexico.

Study of the combined particle identification capability of a transition radiation detector and a silicon imaging calorimeter during the TS93 balloon flight

Abstract The WiZard Collaboration is involved in a program studying the antimatter components of the cosmic rays. A transition radiation detector and a silicon-tungsten calorimeter with imaging capabilities have been built as part of this program. We present the combined performance of these two detectors for positron identification during a balloon flight on September 8, 1993. The flight was dedicated to the measurement of the positron spectrum in the energy range 4–50 GeV and was launched from Ft. Summer, New Mexico.

Identification of cosmic ray electrons and positrons by neural networks

Abstract A data analysis based on artificial neural network classifiers has been done to identify cosmic ray electrons and positrons detected with the balloon-borne NMSU/Wizard-TS93 experiment. The information is provided by two ancillary and independent particle detectors: a transition radiation detector and a silicon-tungsten imaging calorimeter. Electrons and positrons measured during the flight have been identified with background rejection factors of 80 ± 3 and 500 ± 37 at signal efficiencies of 72 ± 3% and 86 ± 2% for the transition radiation detector and silicon-tungsten imaging calorimeter, respectively. The ability of the artificial neural network classifiers to perform a careful multidimensional analysis surpasses the results achieved by conventional methods.