The superconducting magnet system of the alpha magnetic spectrometer AMS-02

The Alpha Magnetic Spectrometer AMS-02 is a particle physics detector designed to search for antimatter, dark matter and the origin of cosmic rays in space. The detector will be installed on the International Space Station in 2005. feature of the detector is a strong superconducting magnet with a bending power Bl2 of approx. 0.8 Tm2. A special arrangement consisting of 14 coils was chosen to create the required field strength while the stray field and the magnetic moment of the magnet are reduced to a minimum. All coils are wound from a high-purity aluminium-stabilized Niobium–Titanium conductor. The magnet is operated at a temperature of 1.8 K using 2500 l of superfluid helium. Since the magnet design is optimized with respect to very low heat losses, the magnet is intended to be operated for 3 years without refilling. The AMS-02 magnet will be the first large superconducting magnet used in space. This paper describes the main features of the AMS superconducting magnet system including the cryogenic system which has been especially adopted for operation under microgravity conditions.