AMS - a magnetic spectrometer on the international space station

The Alpha Magnetic Spectrometer (AMS) is a particle detector, designed to search for cosmic antimatter and dark matter and to study the elemental and isotopic composition of primary cosmic rays, that will be installed on the International Space Station (ISS) in 2008 to operate for at least three years. The detector will be equipped with a ring imaging Cherenkov detector (RICH) enabling measurements of particle electric charge and velocity with unprecedented accuracy. Physics prospects and test beam results are shortly presented.

The RICH detector of the AMS-02 experiment: status and physics prospects

The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV. It is equipped with several subsystems, one of which is a proximity focusing RICH detector with a dual radiator (aerogel+NaF) that provides reliable measurements for particle velocity and charge. The assembly and testing of the AMS RICH is currently being finished and the full AMS detector is expected to be ready by the end of 2008. The RICH detector of AMS-02 is presented. Physics prospects are briefly discussed.

Particle identification with the AMS-02 RICH detector: D/p and anti-D/anti-p separation

The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV, using state-of-the art particle identification techniques. Among several detector subsystems, AMS includes a proximity focusing RICH enabling precise measurements of particle electric charge and velocity. The combination of both these measurements together with the particle rigidity measured on the silicon tracker endows a reliable measurement of the particle mass. The main topics of the AMS-02 physics program include detailed measurements of the nuclear component of the cosmic-ray spectrum and the search for indirect signatures of dark matter. Mass separation of singly charged particles, and in particular the separation of deuterons and antideuterons from massive backgrounds of protons and antiprotons respectively, is essential in this context. Detailed Monte Carlo simulations of AMS-02 have been used to evaluate the detectors performance for mass separation at different energies. The obtained results and physics prospects are presented.

Astrophysics with the AMS-02 experiment

The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV, using state-of-the-art particle identification techniques. Following the successful flight of the detector prototype (AMS-01) aboard the space shuttle, AMS-02 is expected to provide a significant improvement on the current knowledge of the elemental and isotopic composition of hadronic cosmic rays due to its long exposure time (minimum of 3 years) and large acceptance (0.5 m^2 sr) which will enable it to collect a total statistics of more than 10^10 nuclei. Detector capabilities for charge, velocity and mass identification, estimated from ion beam tests and detailed Monte Carlo simulations, are presented. Relevant issues in cosmic ray astrophysics addressed by AMS-02, including the test of cosmic ray propagation models, galactic confinement times and the influence of solar cycles on the local cosmic ray flux, are briefly discussed.

Particle identification with the AMS-02 RICH detector: search for dark matter with antideuterons

The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV, using state-of-the art particle identification techniques. It is equipped with several subsystems, one of which is a proximity focusing Ring Imaging Cherenkov (RICH) detector equipped with a dual radiator (aerogel+NaF), a lateral conical mirror and a detection plane made of 680 photomultipliers and light guides, enabling precise measurements of particle electric charge and velocity (Delta beta / beta ~ 10^-3 and 10^-4 for Z=1 and Z=10-20, respectively) at kinetic energies of a few GeV/nucleon. Combining velocity measurements with data on particle rigidity from the AMS-02 Tracker (Delta R / R ~ 2% for R=1-10 GV) it is possible to obtain a reliable measurement for particle mass. One of the main topics of the AMS-02 physics program is the search for indirect signatures of dark matter. Experimental data indicate that dark, non-baryonic matter of unknown composition is much more abundant than baryonic matter, accounting for a large fraction of the energy content of the Universe. Apart from antideuterons produced in cosmic-ray propagation, the annihilation of dark matter will produce additional antideuteron fluxes. Detailed Monte Carlo simulations of AMS-02 have been used to evaluate the detectors performance for mass separation, a key issue for anti-D/anti-p separation. Results of these studies are presented.