21-25 July 2019
Connecticut Convention Center, Level 6
US/Eastern timezone

C4Or1A-01: Vibration-heating in ADR Kevlar suspension systems

25 Jul 2019, 09:30
15m
Level 6, Room 26-27 ()

Level 6, Room 26-27

Contributed Oral Presentation C4Or1A - Aerospace Cryocoolers III

Speaker

James Tuttle (NASA/GSFC)

Description

The cryogenics group at NASA’s Goddard Space Flight Center has a long-standing development and test program for laboratory and space-flight adiabatic demagnetization refrigerators (ADRs). These devices are used to cool components to temperatures as low as 0.05 K. At such low temperatures the ADR systems can provide a few micro-Watts of cooling power, so it is important to minimize the conduction of heat to these cold stages from the surroundings. The cold ADR elements are held in place by thin tensioned strings made of Kevlar, chosen for its high strength and stiffness and low thermal conductivity. During laboratory testing, we have observed that occasional significant additional heat loads on the coldest ADR stages correlate with unusually high vibration levels in the cryostat due to a noisy mechanical cryocooler. We theorized that this heat results from plastic deformation of the Kevlar fibers and frictional interactions among them, driven by the cryostat vibrations. We describe tests and calculations performed in attempt to confirm this source of the heating, and we discuss possible strategies to reduce this effect in future ADR suspension systems.

Primary author

James Tuttle (NASA/GSFC)

Co-authors

Dr Amir Jahromi (NASA/GSFC) Dr Edgar Canavan (NASA–Goddard Space Flight Center) Michael DiPirro (NASA/Goddard Space Flight Center) Dr Mark Kimball (NASA/Goddard Space Flight Center) Peter Shirron (NASA/GSFC) Chloe Gunderson (University of Wisconsin, Madison) Jacob Nellis (University of Wisconsin)

Presentation Materials

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