[en] The Alpha Magnetic Spectrometer (AMS-01) has successfully performed in a precursor flight in June 1998. The experiment is scheduled for a 3-year operation on the International Space Station (ISS) in the year 2003. For the ISS flight, the completion of the tracker as well as a major upgrade of the detector (AMS-02) is in progress. In this contribution, we present results from the AMS-01 silicon tracker construction and describe the organization of the assembly for phase 2. Given the large scale of this silicon detector, the involvement of private industries in the construction is addressed

[en] The design of the high precision microstrip silicon tracker for the Alpha magnetic spectrometer experiment (AMS) is presented. We emphasize features of the silicon tracker which make it suitable for a space born experiment and for equipping large active areas. (orig.)

[en] The accuracy on the measurments of the Z⁰ width foreseen at LEP/SLC will be limited by the error on the normalization from the small angle luminosity monitors at the level of a few per cent. We show how the measurement of large angle e⁺e^- events produced near to the Z⁰ pole will enable a much more accurate measurement of Γ_z or Γ_ee/Γ_z to be made, as soon as the integrated luminosity is larger than ≅ 1 pb^-1. This measurement is free from most systematic errors affecting the other proposed techniques. Using this method, the expected ultimate relative accuracy on Γ_ee/Γ_z is ≅ 1.10^-3 (1.5.10^-2 neutrino families) after ≅ 10⁷ Z⁰. (orig.)

[en] We have studied the characteristics of CF₄-based nonflammable gas mixtures for plastic streamer tubes. For various combinations of CF₄ + hydrocarbon and CF₄ + hydrocarbon + Ar we measured the singles counting rate plateau, the charge spectrum and the average drift time over the cell. The hydrocarbons used were respectively isobutane, n-pentane and n-hexane. The stability of these mixtures is good, and their spurious streamer activity is compared with the standard binary or ternary mixture. The drift velocity is at least twice as high as in the standard mixtures. (orig.)

[en] First results for the AMS silicon tracker readout performance are presented. Small 20.0x20.0x0.300 mm³ silicon microstrip detectors were installed in a 50 GeV electron beam at CERN. The detector readout consisted of prototypes of the tracker data reduction card equipped with a 12-bit ADC and the tracker frontend hybrid with VA_hdr readout chips. The system performance is assessed in terms of signal-to-noise, position resolution, and efficiency

[en] Tracking with silicon strip detectors for relativistic ions has been investigated using a ¹²C beam of 1.5 GeV/u at GSI. The ionization charge spectrum and the charge sharing between strips are presented. The strip cluster of carbon ion can be selected based on the cluster charge with high efficiency and little contamination. The spatial resolution of the silicon strip detectors is evaluated. The angular distribution of multiple Coulomb scattering was investigated with lead absorbers. The results are compared to the Moliere theory and the Gaussian approximation of GEANT calculations. (author)

[en] The Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) for an operational period of 3 years. The AMS is the first cosmic ray spectrometer equipped with a large area silicon tracker (>5 m²). A preliminary version of the detector was flown on the NASA space shuttle Discovery during June 2-12, 1998. Results for the dimensional stability of the silicon tracker planes based on the flight data, and the metrology data recorded before and after the flight, are presented

[en] The gas mixtures generally used until now in limited streamer tube detectors (Ar + C₄H₁₀ or Ar + CO₂ + C₅H₁₂) are very flammable when leaked into air. The safety issues are therefore very relevant for large-volume underground experiments. We have found a set of completely safe (i.e. nonflammable) ternary mixtures of the kind Ar + hydrocarbon + CO₂ containing less than ≅ 5% of Ar and less than ≅ 10% of hydrocarbon. We tested C₄H₁₀, C₅H₁₂ and C₆H₁₄ as quenching agents. The main characteristics of the various mixtures have been measured: singles (untriggered) counting rate versus high voltage and with different dead times, and average charge. The stability of these mixtures is good, and their spurious streamer activity is compared with the standard binary or ternary mixture. We studied in particular the combination Ar(2.5%) + C₄H₁₀(9.5%) + CO₂(88%). All the data suggest that this or a similar gas mixture can successfully replace standard flammable mixtures both in tracking devices and hadron calorimeters. (orig.)

[en] The Alpha Magnetic Spectrometer (AMS01), a high-sensitivity particle spectrometer, was successfully flown for 10 d in June 1998 (STS91) in the orbit of the International Space Station (51.7 deg., ∼380 km). A high-statistics dataset of galactic cosmic rays were measured as a function of geomagnetic latitude, including the primary protons, leptons and helium as well as the trapped and quasi-trapped proton and lepton components. In this paper, the absorbed dose rate owing to the protons, leptons and helium are presented and compared with measurements made by other instruments flown on the same mission. (authors)

[en] High-precision tracking and charge selection with silicon strip detectors for relativistic ions has been investigated using a ¹²C beam of 1.5 GeV/u at GSI with prototype modules developed for the AMS tracker. The ionization energy loss is measured and compared to the Landau-Vavilov theory for ions of charge number up to Z=6. The linearity in Z² is examined. The capability to distinguish different Z values based on the ionization energy loss is evaluated. The spatial resolution of the silicon strip detectors is investigated for carbon ions. The angular distribution of multiple Coulomb scattering is studied with lead absorbers. The results are compared to the Moliere theory and the Gaussian approximation of GEANT calculations