[show abstract][hide abstract] ABSTRACT: 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.
[show abstract][hide abstract] ABSTRACT: The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.
[show abstract][hide abstract] ABSTRACT: Cosmic ray (CR) nuclei are accelerated particles which move randomly through the interstellar medium (ISM), where they suffer
scattering, reacceleration and energy loss processes before reaching Earth. Spallation processes also take place forming secondary
nuclei by fragmentation of heavier ones. Due to the impossibility of observing directly their original direction, the determination
of possible sources where these particles originated requires the use of codes to simulate the propagation of CR within the
Galaxy. This consists of a spiral disk with a thickness of 2h ~ 200 pc, where CR are created, and a halo with a height H,
where they diffuse.
[show abstract][hide abstract] ABSTRACT: The AMS experiment includes a Cherenkov imager for mass and charge identification of charged cosmic rays. A second generation prototype has been constructed and its performances evaluated both with cosmic ray particles and with beam ions. In-beam tests have been performed using secondary nuclei from the fragmentation of per nucleon Pb ions and per nucleon In from the CERN SPS in 2002 and 2003. Partial results are reported. The performances of the prototype for the velocity and the charge measurements have been studied over the range of ion charge Z≲30. A sample of candidate silica aerogel radiators for the flight model of the detector has been tested. The measured velocity resolution of the detector was found to scale with Z-1 as expected, with a value σ(β)/β≈0.7–110-3 for singly charged particles and an asymptotic limit in Z of 0.4–0.6×10-4. The measured charge resolution obtained for the n=1.05 aerogel radiator material selected for the flight model of the detector is σ(Z)=0.18 (statistical) ⊕ 0.015 (systematic), ensuring a good charge separation up to the iron element, for the prototype in the reported experimental conditions.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 05/2006;
[show abstract][hide abstract] ABSTRACT: The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.
[show abstract][hide abstract] ABSTRACT: We will analyze the importance of varying the diffuse gas radial distribution on the resulting expected cosmic rays spectrum. We use the recent HI density data published by Nakanishi et al. (2004), and include them in the cosmic rays propagation code GALPROP (Strong & Moskalenko 1998). We will obtain those models that reproduce the characteristics shown by the cosmic rays data, and we will then extract information about the Galaxy structure.
[show abstract][hide abstract] ABSTRACT: In this note, we report the results of a simulation of the galactic component of high energy gamma rays, as seen by the future AMS-02 experiment on-board the International Space Station. The purpose of AMS is to measure the Cosmic Ray spectra of numerous particles with unprecedented accuracy. This simulation has been performed with the GALPROP code and its output interfaced with the AMS Fast Simulator, to produce a sky-map of yearly counts in the AMS energy range (over 1 GeV).
[show abstract][hide abstract] ABSTRACT: We report on the performance of the (alpha magnetic spectrometer) AMS Cerenkov counter prototype under a beam of light ions at CERN SPS. In particular the efficiency to determine the velocity and the charge of the incoming particles is studied for different radiators.
Instrumentation and Measurement Technology Conference, 2004. IMTC 04. Proceedings of the 21st IEEE; 06/2004
[show abstract][hide abstract] ABSTRACT: A prototype of the AMS Cherenkov imager (RICH) has been tested by means of a low intensity per nucleon ion beam coming from the fragmentation of a primary beam of Pb ions. Data have been collected for charges 1<Z<∼45 in various beam conditions and using different radiators. The charge Z and velocity β resolution have been of the prototype investigated.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2004;
[show abstract][hide abstract] ABSTRACT: A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.