The Alpha Magnetic Spectrometer Superconducting Magnet

The Alpha Magnetic Spectrometer (AMS) is designed to search for antimatter, dark matter and astrophysics observables. After the successful flight of AMS-01 aboard the Space Shuttle mission STS-91 in 1998, the AMS collaboration developed and is assembling a highly improved detector AMS-02, which will be operated on the International Space Station (ISS). The superconducting magnet consists of a pair of dipole coils and two sets of six flux return coils. This arrangement greatly reduces the magnetic stray field to minimize torque on ISS caused by interaction of the magnet field with the Earth’s magnetic field. The magnet is cooled at a temperature of 1.8 K by evaporation of 2500 litres of superfluid helium. We expect an operation time in space of 3 years without refilling the helium. Of the superconducting magnet hardware, approximately 90 % is complete. This paper reviews the status of the first large superconducting magnet for a space application, and the main features of the cryogenic system under micro-gravity conditions