Cryogenic system for a large superconducting magnet in space

The Alpha Magnetic Spectrometer (AMS) is a particle physics experiment for use on the International Space Station (ISS). At the heart of the detector will be a large superconducting magnet cooled to a temperature of 1.8 K by 2500 liters of superfluid helium. The magnet and cryogenic system are currently under construction by Space Cryomagnetics Ltd of Culham, England. This paper describes the cryogenic system for the magnet, designed for the unusual challenges of operating a superconducting system in space. Results from experiments demonstrating some of the new techniques and devices developed for the magnet cryogenics are also presented.