F. Taccetti

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.

Further study of CdWO4 crystal scintillators as detectors for high sensitivity 2β experiments: Scintillation properties and pulse-shape discrimination

Abstract Energy resolution, non-proportionality in the scintillation response, α / β ratio, pulse shape for γ rays and α particles were studied with CdWO 4 crystal scintillators. Some indication for a difference in the emission spectra for γ rays and α particles was observed. No dependence of CdWO 4 pulse shape on emission spectrum wavelengths under laser, α particles and γ ray excitation was observed. Dependence of scintillation pulse shape for γ quanta and α particles and pulse-shape discrimination ability on temperature was measured in the range of 0–24xa0°C.

Radiation shielding of spacecraft in manned interplanetary flights.

Abstract During the interplanetary flights the crewmembers will be exposed to cosmic ray radiation with great risk for their health. The absorbed dose due to CR depends on the galactic (GCR) or solar (SCR) origin. GCRs are isotropic and relatively high in energy and deliver a dose nearly constant with time that can be reduced only by means of “heavy” passive protection. The outer walls of the spacecraft usually shield the SCRs up to a few tens of MeV, but during some exceptional solar bursts, a great number of particles, mainly protons, are ejected at higher energies. In this case the dose delivered in a few hours by a solar burst can easily exceed 1 year cumulated dose by GCRs. The high-energy component of SCRs is quasi-directional so that a shielding system based on a superconductive magnetic lens can reduce the daily dose of SCRs to the level delivered by GCRs.

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.

Response of CdWO4 crystal scintillator for few MeV ions and low energy electrons

The response of a CdWO4 crystal scintillator to protons, α particles, Li, C, O and Ti ions with energies in the range 1 – 10 MeV was measured. The non-proportionality of CdWO4 for low energy electrons (4 – 110 keV) was studied with the Compton Coincidence Technique. The energy dependence of the quenching factors for ions and the relative light yield for low energy electrons was calculated using a semi-empirical approach. Pulse-shape discrimination ability between γ quanta, protons, α particles and ions was investigated.

Spatial resolution of double-sided silicon microstrip detectors for the pamela apparatus

Abstract 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 μ m in the bending coordinate). A complete simulation of the silicon microstrip detectors has been developed in order to investigate in great detail the sensors 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 particles incidence angle and the cluster multiplicity, so as to maximize the capability of the spectrometer in antiparticle tagging.

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 silicon tracker of the PAMELA experiment

Abstract We describe the silicon tracker that is actually under construction for the PAMELA spectrometer. The readout electronics has been optimized in order to greatly reduce power consumption while providing the very good reliability needed for spatial applications. The silicon sensors used have been fabricated using double-sided, double-metal, AC-coupled technology. A description of the design steps and of the technological choices made, will be given. Finally, we present the results obtained during a beam test using both minimum and non minimum ionizing particles to study the behaviour of the whole system.

The microstrip silicon tracker of the PAMELA experiment

SummaryThe trackingsystem for the PAMELA spectrometer is actually under construction usingdouble-sided double metal AC coupled microstrip silicon sensors. To study the performances of the silicon detectors and of the readout electronics several tests have been performed, usingminimum ionizingparticles. The characteristics of the detectors are described and the main results obtained from the July ’97 test-beam are presented, with particular reference to the spatial resolution.