Spatial Resolution of Double-Sided Silicon Microstrip Detectors for the PAMELA Apparatus

The PAMELA apparatus has been assembled and it is ready to be launched in a satellite mission to study mainly the antiparticle component of cosmic rays. In this paper the performances obtained for the silicon microstrip detectors used in the magnetic spectrometer are presented. This subdetector reconstructs the curvature of a charged particle in the magnetic field produced by a permanent magnet and consequently determines momentum and charge sign, thanks to a very good accuracy in the position measurements (better than 3 um in the bending coordinate). A complete simulation of the silicon microstrip detectors has been developed in order to investigate in great detail the sensor's characteristics. Simulated events have been then compared with data gathered from minimum ionizing particle (MIP) beams during the last years in order to tune free parameters of the simulation. Finally some either widely used or original position finding algorithms, designed for such kind of detectors, have been applied to events with different incidence angles. As a result of the analysis, a method of impact point reconstruction can be chosen, depending on both the particle's incidence angle and the cluster multiplicity, so as to maximize the capability of the spectrometer in antiparticle tagging.Comment: 28 pages, 18 figures, submitted to Nuclear Instruments and Methods in Physics Research

First flight data from the PAMELA spectrometer

Abstract PAMELA is a satellite-borne experiment designed to study charged particles in the cosmic radiation, optimized in particular for antimatter components search. The experiment is mounted on the Resurs DK1 satellite that was launched on June 15th 2006 from Baikonur cosmodrome and is now collecting data from a semi-polar elliptical orbit around the Earth. The core of the PAMELA apparatus is a magnetic spectrometer, designed to determine precisely the rigidity and the absolute charge of particles crossing the detector. The tracking system is composed of six planes of silicon microstrip detectors dipped in an almost uniform magnetic field generated by a permanent magnet made of an Nd–Fe–B alloy. Some preliminary analysis about the spectrometer's performances, made using data collected since July 2006 till June 2007, are here reviewed

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.Comment: To be published on Astroparticle Physics (44 pages, 13 figures, 5 tables

Status of the PAMELA silicon tracker

PAMELA is a composite particle detector which will be launched during the first half of 2006 on board the Russian satellite Resurs DK-1 from Baikonur cosmodrome in Kazakhstan. This experiment is mainly conceived for the study of cosmic-ray antiparticles and for the search for light antinuclei, but other issues related to the cosmic-ray physics will be investigated. In this work the structure of the whole apparatus is shortly discussed with particular attention to the magnetic spectrometer, which has been designed and built in Firenze

A powerful tracking detector for cosmic rays: the magnetic spectrometer of the PAMELA satellite experiment

Abstract The WiZaxd-PAMELA detector will be ready within some months to be installed on board of the Russian satellite Resurs-DK1. The satellite will follow, for at least 3 years, a quasi polar orbit with an inclination of 70.4° with respect to the equatorial plane. The experiment will allow the measurement of the antiproton and positron spectra within a wide momentum range and the search for light anti-nuclei in cosmic rays. The detector subsystems have been tested and the final assembly phase is in progress. In this paper we describe the structure of the PAMELA magnetic spectrometer, its current status and some precautions taken to satisfy the requirements of the mission

The magnetic spectrometer of the PAMELA satellite experiment

In this paper, we describe in detail the design and the construction of the magnetic spectrometer of the PAMELA experiment, that will be launched during 2003 to do a precise measurement of the energy spectra of the antimatter components in cosmic rays. This paper will mainly focus on the detailed description of the tracking system and on the solutions adopted to deal with the technical challenges that are required to build a very precise detector to be used in the hostile space environment

The silicon microstrip detectors of the PAMELA experiment: simulation and test results

Abstract The PAMELA detector will fly at the beginning of 2004 on board the Russian satellite Resurs–DK for a 3-year mission designed to study mainly antiparticles in cosmic rays. The core of the apparatus is a magnetic spectrometer in which silicon microstrip detectors are employed. A dedicated simulation study, tuned on beam test data, is presented: it allows to determine the best position finding algorithm for different incidence angles

The PAMELA silicon tracker

Abstract The silicon tracker of the PAMELA apparatus has been assembled and it is ready to fly on-board the Russian satellite Resurs DK for a 3-year mission. The experiment will study, mainly, spectra of particles and antiparticles in cosmic rays. The magnetic spectrometer's primary goal is to precisely measure momenta of charged particles, whose trajectories have been bent by a permanent magnet. The detector is composed of 6 planes of double-sided silicon microstrip detectors, inserted between adjacent modules of a permanent magnet which produces an almost uniform magnetic field inside a rectangular cavity that particles cross. The spatial resolution of the detectors is about 3 μm for the bending coordinate. The development of such detectors required a complex manufacturing procedure in order to preserve the physical performance in a device suitable for a space mission. In the construction phase data originating from both beam tests and simulation helped to check the detector's characteristics and to optimize the achievable spatial resolution. The development and the final assembling of these detectors are described in this paper

Pamela tracking system: status report

The Pamela apparatus will be launched at the end of 2002 on board of the Resurs DK Russian satellite. The tracking system, composed of six planes of silicon sensors inserted inside a permanent magnetic field was intensively tested during these last years. Results of tests have shown a good signal-to-noise ratio and an excellent spatial resolution, which should allow to measure the antiproton flux in an energy range from 80 MeV up to 190 GeV. The production of the final detector modules is about to start and mechanical and thermal tests on the tracking tower are being performed according to the specifications of the Russian launcher and satellite. r 2002 Elsevier Science B.V. All rights reserved