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 (ADR) for the Submillimeter and Far Infrared Experiment (SAFIRE), a payload on the Stratospheric Observatory for Infrared Astronomy (SOFIA). SAFIRE will use superconducting detectors which must be shielded from the magnet cooling system. Because the detectors use Superconducting Quantum Interference Devices (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 programs.