| ABSTRACT: |
The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment in space.
The purpose is to perform accurate and long-duration measurements
of the spectra of charged cosmic rays (CRs) from GeV to multi-TeV energy,
and also to allow the searching for primordial antimatter and possible dark matter annihilation signals.
Recently the question of dark matter in the Universe has been put into focus,
as the positron excess observed by new generation CR detectors could be tentatively
interpreted in terms of indirect signature of dark matter annihilation.
In addition, the recently collected data indicate a break of the spectra of
the most abundant CR species above the rigidity of a few hundred GV.
AMS-02 would be the unique existing experiment to significantly improve the accuracy
of the measurement of the composition of anti particles, as well as primary CR spectra.
The data taking of AMS-02 began on the 19th of May, 2011 after the successful launch of
space shuttle STS-134 and the installation of the spectrometer on the International Space Station (ISS).
Seven planes of Silicon sensors in the permanent magnet (0.15T) bore and
two planes at the ends of the detector act as tracking device.
The measurement of the curvature of the charged particles allows the estimation
of particle rigidity and charge sign. Transition Radiation Detector (TRD) and Electromagnetic
calorimeter (Ecal) give us independent separation power of electrons and positrons
from protons and antiprotons. Exploiting a large acceptance (~0.5 m2sr) and a data taking of at least 10 years,
AMS”¾02 should be able to collect far more particle events than ever achieved in the other experiments.
In the seminar, the status of the spectrometer, its performances and potentialities
after the first months of data taking in space will be discussed. |
