Product

Model 16PT-ADR Cryogen Free Two Stage Adiabatic Demagnetization Refrigerator System

The system consists of the following components:

• Model 16PT cryo-cooled superinsulated helium cryostat containing an adiabatic demagnetization refrigerator (ADR) system. The cryostat includes a model PT405 Pulse Tube refrigerator with internal highly conductive flexible thermal linkage to cool two stages, the ADR support stages, a superconducting magnet and associated leads and thermometry. It also cools two sets of radiation shields that protect the cold assembly from the room temperature radiational heat load. The system also includes appropriate getters and provisions for thermal anchoring of additional wiring for the end users’ experiments.
• A two stage ADR system with a gadolinium-gallium garnet (GGG) crystal and a ferric ammonium alum (FAA) salt pill. Each pill has its own ultra low thermal conducting support structure isolating it from the 4 K flange and the intermediate stage. The two stages operate at a temperature of ~1 K (GGG) and 50 – 100 mK (FAA), with a typical hold time of three days below 100 mK.
• A mechanical thermal heat switch assembly for attaching and detaching the two stages of the ADR during initial cool down, and during its magnetization and demagnetization cycles.
• Two ruthenium oxide thermometers with appropriate heat sunk wiring at the various intermediate stages to monitor the temperature of the two stages of the ADR. The two thermometers are supplied with a standard calibration data between 50 mK and 20 K.
• A 4 Tesla conductively cooled multi-filamentary Niobium-Titanium superconducting magnet surrounding the GGG and FAA pills. The magnet is wired with an optimized arrangement of low and high temperature superconducting leads, and is provided with voltage taps and two standard thermometers to monitor its cool down and operating temperature. The magnet reaches its rated field of 4 Tesla at a nominal 10 amperes.
• A high permeability magnetic shield surrounding the magnet and the two pills, to reduce the stray magnetic field in the vicinity of the cold stages.
• Complete wiring, interfacing and testing of all components, including the ADR pills, magnet, thermometry, and helium readout. This includes a final test of the complete system, to ensure precise dewar and ADR hold time and operation.

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