John MurphyMasters of Science Mechanical EngineeringAdvisors: Franklin Miller & Greg Nellis

Office: 1335 ERBEmail: jbmurphy2@wisc.eduHometown: Branchburg, NJ

Manufacturing a Piezoelectric Actuated Seat Valve for a Cold Cycle 3He-4He Dilution Refrigerator for milliKelvin Cooling

Motivation• As quantum information systems scale up, cooling below 100 mK will be needed for larger

systems.

• The development of the piezoelectric valve will allow the reversible pump to generate the continuous flow needed to drive the cold cycle dilution refrigerator (CCDR).

• Quantum systems will solve many problems that traditional computers struggle with because they can take advantage of the qubits superposition and entanglement characteristics.• Encryption and optimization are two areas where quantum systems are expected to succeed.

Background• This valve design, when combined with the

superfluid magnetic pump, gives the unidirectional flow required for the CCDR with no circulation to room temperature and no mechanical connections to room temperature.

• With Professor Miller’s experience with the design, fabrication, and testing of various cryogenic refrigeration systems and low temperature valves, the foundation of the proposed work has been demonstrated as part of his PhD research at MIT.

Goals• Design, build, and test the piezoelectric superfluid helium valves necessary to rectify the

superfluid magnetic pump flow so that it can be used to drive the CCDR cycle.

• The valves remove the requirement of circulating the 3He-4He mixture to room temperature, resulting in a more compact CCDR.

• Show that the piezoelectric actuated valve can run continuously so cooling down to 100 mK and that the valve will properly open and close with the piezo actuator at 40 K.