Brad MooreM.S. StudentRoom: 1337507 884 9258Hometown: Rochester, MN

Thesis: Development of a Passive Check Valve for Cryogenic Applications

Astrophysics missions employing Microcalorimetry and Transition edge sensors have a need for sub-Kelvin (<1K) cooling.

A Cold Cycle Dilution Refrigerator (CCDR) provides an alternative to the current space based sub-kelvin cooling - Adiabatic Demagnetization Refrigerators or LHe3 Cryostats.

The CCDR provides cooling through the endothermic mixing of He3-He4 isotopes at low temperatures.

A reversible paramagnetic pump drives the flow through the cycle, however the flow provided is oscillating and must be rectified through the use of check valves.

Background

Development, fabrication and testing of a check valve for use in the CCDR.

Requirements: Passive – no electric or mechanical actuation Operate at low temperatures (~1.8 K) with a mixture

of He3-He4. Seal at low back pressures (~3psi) Negligible cracking pressure required to open

Objectives

Check ValveTeflon seat reed check valve currently being refined and tested.