Amir E. Jahromi

M.S. Graduate Student Mechanical Engineering

Thesis:

Development of a Cryogenic Magnetic Pump

     Cryogenic detectors in new infrared and X-ray astrophysics missions need to be cooled to temperatures below 1 Kelvin. Single shot adiabatic demagnetization refrigerator (ADR) and the 3 He evaporation refrigerators are the state of the art.

These systems cannot cool continuously therefore they need to be recycled periodically. As a result, the detectors are not cooled continuously. Continuous sub Kelvin refrigeration cycles have been developed but they required compressors with moving mechanical parts.

This new pump will enable continuous sub Kelvin refrigeration cycles without moving mechanical parts.

   The cryogenic magnetic pump will consist of two canisters filled with Gadolinium Gallium Garnet (GGG- a paramagnetic salt) with a 3 He 4 He mixture surrounding it. The magnetization of the superconducting magnets will heat up the contained He mixture and the pressure of the He mixture will increase due to the superfluid fountain effect.

This pump will be free of any moving mechanical parts.

    A numerical and analytical analysis will be done in order to determine the dimensions and sizing of the pump. The pump beds and the superconducting magnetic coils will be constructed and assembled according to the numerical analytical solutions.

The cryogenic magnetic pump will be tested and final results will be evaluated and compared against the previously obtained numerical and analytical results. The pump will be refined based on experimental and numerical-analytical results.