The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be) and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.

Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35–45 GeV nucleon−1. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5–6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%–15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.

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A measurement of the cosmic ray positron fraction e+/(e++e−) in the energy range of 1–30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 106 is reached by identifying converted bremsstrahlung photons emitted from positrons.

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the ∼100 MeV to 1 TeV range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle Discovery from June 2 to June 12, 1998, and collected 108 cosmic ray triggers. Part of the Mir space station was within the AMS-01 field of view during the four day Mir docking phase of this flight. We have reconstructed an image of this part of the Mir space station using secondary π− and μ− emissions from primary cosmic rays interacting with Mir. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.

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 (>5m2). 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.

The helium spectrum from 0.1 to 100 GeV/nucleon was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at altitudes near 380 km. Above the geomagnetic cutoff the spectrum is parameterized by a power law. Below the geomagnetic cutoff a second helium spectrum was observed. In the second helium spectra over the energy range 0.1 to 1.2 GeV/nucleon the flux was measured to be (6.3 +/- 0.9) x 10(-3) (m(2) sec sr)(-1) and more than ninety percent of the helium was determined to be He-3 (at the 90% CL). Tracing helium from the second spectrum shows that about half of the 3He travel for an extended period of time in the geomagnetic field and that they originate from restricted geographic regions similar to protons and positrons. (C) 2000 Published by Elsevier Science B.V.

The lepton spectra in the kinetic energy ranges 0.2 to 40 GeV for e(-) and 0.2 to 3 GeV for e(+) were measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at altitudes near 380 km. From the origin of the leptons two distinct spectra were observed: a higher energy spectrum and a substantial second spectrum with positrons much more abundant than electrons. Tracing leptons from the second spectra shows that most of these leptons travel for an extended period of time in the geomagnetic field and that the e(+) and e(-) originate from two complementary geographic regions. (C) 2000 Elsevier Science B.V. All rights reserved.

High-precision tracking and charge selection with silicon strip detectors for relativistic ions has been investigated using a 12C beam of 1.5GeV/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 Molière theory and the Gaussian approximation of GEANT calculations.

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux similar to 70m(-2) s(-1) sr(-1). Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

The primary proton spectrum in the kinetic energy range 0.2 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle Right STS-91 at an altitude of 380 km. The complete data set combining three shuttle attitudes and including all known systematic effects is presented. (C) 2000 Elsevier Science B.V. All rights reserved.

The Alpha Magnetic Spectrometer (AMS) is designed as an independent module for installation on the International Space Station (ISS) in the year 2003 for an operational period of three years. The principal scientific objectives include the searches for antimatter and dark matter in cosmic rays. The AMS tracker uses silicon microstrip sensors to reconstruct charged-particle trajectories. A first version of the AMS, equipped with 2.1 m2 of silicon sensors and a permanent magnet, was flown on the NASA space shuttle Discovery duringJune 2–12, 1998. In this contribution, we describe the detector and present results of the tracker performance duringthe flight.

In the framework of silicon detector development for high energy and space applications, we have performed a number of environmental tests on different devices. Most of the effects we have detected during the construction phases are possibly due to external contamination to the detector surface, as well as to electrostatic effects at surfaces and interfaces, with possible consequences on our future design, production and construction activities.

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.

A prototype of a readout system developed for high spatial precision tracking detectors at LHC has been tested in a beam at CERN. It is based on a radiation hard CMOS front-end chip which includes signal amplification, storage in an analogue delay line and a deconvolution filter. Data were transferred from the front-end chip using an analogue fibre optic link employing a novel reflective electro-optic modulator and continuous laser light source remote from the detector. This is the first time such a system has been used in an experimental environment and is the basis of the system proposed for the CMS experiment at LHC.

The Large Hadron Collider (LHC) is in preparation at CERN, and the ATLAS (A Toroidal LHC Apparatus) and CMS (Compact Muon Solenoid) Collaborations have recently presented Technical Proposals for the construction of two general purpose experiments. Even though ATLAS and CMS are primarily conceived and optimized for high-luminosity LHC operation, namely in view of Standard Model and Minimal Supersymmetric Standard Model Higgs searches, the first few years of low-luminosity operation, thanks to the high centre-of-mass energy of the LHC collider experiments with two 7 TeV proton beams, will also allow investigation of B-physics issues, which are influencing the designs of the detectors. Prospects for B physics will be described and compared, in particular CP violation, with time-dependent and time-integrated asymmetries for different channels and related sensitivities to the CP-violating parameters, oscillations and rare decays. Conclusions and possible improvements will be summarized.

During the beam test of a tracker prototype for the Compact Muon Solenoid detector proposed for the LHC, the time response of the Microstrip Gas Chambers was studied using different gases and chamber gaps. The subsequent efficiency to identify the bunch crossings at LHC is discussed for several algorithms used in the off-line signal processing of the data.

A prototype of the barrel Tracking Detector of the Compact Muon Solenoid (CMS) experiment proposed for LHC was built and tested in a beam and in a magnetic field of up to 3 T. It contained six microstrip gas chambers, 25 cm long, and three double-sided silicon microstrip detectors, 12.5 cm long. We report some preliminary results on the performance of the chambers.

The RD20 collaboration is investigating the design and operation of an LHC inner tracking detector based on silicon microstrips. Measurements have been made on prototype detectors after irradiation with electrons, neutrons, photons, and protons for doses up to 5 Mrad and fluences up to 1015 particles/cm2. The annealing of effective doping changes caused by high neutron fluences, one of the major limits to detector lifetime at the LHC, is shown to be strongly inhibited by cooling below room temperature. Detailed results are presented on the critical issue of microstrip capacitance. We have also investigated bulk damage caused by high-energy protons, interstrip isolation after neutron irradiation, and MOS capacitors irradiated with electrons and photons.