AMS-02 Tracker Research Articles

Active CO2 two-phase loops for the AMS-02 tracker

The Alpha Magnetic Spectrometer AMS-02 [1]-[4] is an astro particle physics experiment running on the International Space Station (ISS; see Figure 1) since May 19, 2011. Its missions include the search for antimatter and the identification of the nature of dark matter. The AMS silicon tracker is the only subdetector inside the AMS permanent magnet that can detect the charge of a moving particle to distinguish an anti-particle from particle (see Table 1 for nomenclature).

The AMS-02 silicon tracker: First year on ISS in space

The AMS-02 particle physics experiment was installed on the International Space Station in May 2011 and is taking cosmic ray data since then. Its tracker, with a total active area of 6.75m2, is made of silicon microstrips detectors in the field of a permanent magnet. It measures the rigidity and charge sign and identifies the ion species by dE/dx. The status of the AMS-02 tracker and its operation, after first months of data taking in space, is presented, as well as its performances and potentialities.

Stable and self-adaptive performance of mechanically pumped CO2 two-phase loops for AMS-02 tracker thermal control in vacuum

Abstract A mechanically pumped CO 2 two-phase loop cooling system was developed for the temperature control of the silicon tracker of AMS-02, a cosmic particle detector to work in the International Space Station. The cooling system (called TTCS, or Tracker Thermal Control System), consists of two evaporators in parallel to collect heat from the tracker’s front-end electronics, two radiators in parallel to emit the heat into space, and a centrifugal pump that circulates the CO 2 fluid that carries the heat to the radiators, and an accumulator that controls the pressure, and thus the temperature of the evaporators. Thermal vacuum tests were performed to check and qualify the system operation in simulated space thermal environment. In this paper, we reported the test results which show that the TTCS exhibited excellent temperature control ability, including temperature homogeneity and stability, and self-adaptive ability to the various external heat flux to the radiators.

The AMS-02 silicon tracker: Recent results and current status

The AMS-02 tracker consists of eight layers of double-sided silicon microstrip sensors which are used to measure the particle rigidity in the 0.8 T field of a cylindrical superconducting magnet. The magnetic spectrometer is designed to operate on the International Space Station (ISS) to provide an unprecedented high precision measurement of the cosmic-ray spectra in the energy range between 1 GeV and several TeV, for particle charge up to Z = 26 .

Construction and qualification of the Power Supply system of the AMS-02 Tracker detector

The AMS-02 Tracker power supply system, described in this paper, has been designed optimizing noise performances, modularity and efficiency. The power is distributed starting from a 28V line coming from the power distribution system is converted into the needed voltages by means of DC-DC converters, and for bias supply and front-end voltages is post-regulated by means of linear regulators. Components Off The Shelf (COTS) have been extensively used in the construction of this power supply, however various radiation test campaigns have been performed in order to verify the reliability of these components. The power supply architecture developed for the tracker detector has been used as a guideline for the development of the power supplies for the other detectors in the experiment.

The Anti-Coincidence Counter shield of the AMS tracker

The AMS-02 tracker is surrounded by a highly efficient scintillator screen, the Anti-Coincidence Counter (ACC). It is used for suppressing tracks from outside the main tracker acceptance. We describe methods to ensure that the ACC works at very high efficiency and a high degree of homogeneity.

Development of the power supply system for the AMS-02 tracker detector

This article describes the performance and the architecture of the power supply system for the Tracker detector in the AMS-02 experiment. Qualification tests results on assembled crates will be also presented. The AMS-02 experiment will be installed in the International Space Station (ISS); it will measure the cosmic ray spectrum from 0.5 GeV up to several TeV looking for anti-matter, dark matter and strange quark matter. A preliminary version of the experiment has successfully flown in 1998 on the STS-91 space shuttle flight. The power supply system for the Tracker detector was used as a guideline for the other power supply systems in the experiment.

The AMS-02 tracker alignment system for 3D position control with artificial laser generated straight tracks

AMS-02 is a space (ISS) based charged particle tracking experiment. An IR (1082 nm) laser alignment control system will be installed with its Si-tracker. From the Laser beam signals recorded by the charged particle Si-sensors their position can be monitored in 3D with high accuracy.

Charge determination of nuclei with the AMS-02 silicon tracker

The silicon tracker of the AMS-02 detector measures the trajectory in three dimensions of electrons, protons and nuclei to high precision in a dipole magnetic field and thus measures their rigidity (momentum over charge) and the sign of their charge. In addition, it measures the specific energy loss of charged particles to determine the charge magnitude. Ladders from the AMS-02 tracker have been exposed to ion beams at CERN and GSI to study their response to nuclei from helium up to the iron group. The longest ladder, 72 × 496 mm 2 , verified in the tests contains 12 sensors. Good charge resolution is observed up to iron.

The Si tracker for the AMS-02 experiment on the Space Station

The AMS-02 particle spectrometer will be installed on the International Space Station (ISS) in fall 2005. We describe the design of the 7 m 2 AMS-02 tracker, which is based on the experience with AMS-01—successfully operated in space for 10 days in 1998. We report on beamtests with AMS-02 ladders showing that the charge of cosmic particles can be measured up to rigidities of 3 TV . The novel AMS tracker alignment control scheme based on IR laser rays detected by the Si sensors is described briefly.