Magnetic shielding for sensitive detectors

This paper describes the design and test of shielding for a superconducting magnet, The magnet is part of an Adiabatic Demagnetization Refrigerator (A DR) for the Submillimeter and Far Infrared Experiment (SAFIRE), a payload o n the Stratospheric Observatory for Infrared Astronomy (SOFIA). SAFIRE will use superconducting detectors which must be shielded from the magnet cooli ng system. Because the detectors use Superconducting Quantum Interference D evices (SQUIDs), the field at the detector package must remain at or below the 10(-7) T level while the detectors are operating. We discuss laboratory tests of the passive shielding and simulations using Poisson group program s. (C) 2001 Published by Elsevier Science Ltd.