NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
5-year lifetime hybrid superfluid helium dewar for the AXAF X-Ray Spectrometer (XRS)The focal plane of the AXAF X-Ray Spectrometer requires an operating temperature of 0.1 K with a mission lifetime of 5 yrs. This demanding task is accomplished with a hybrid cryogenic subsystem consisting of mechanical coolers, a superfluid helium dewar and an adiabatic demagnetization refrigerator. By using mechanical coolers to remove heat from the dewar outer vapor-cooled shield, a 5-yr lifetime is achievable with only a 483-liter tank. This approach takes advantage of flight-proven, high-performance dewar technology and recent success in the development of split, Stirling-cycle mechanical coolers. Although the dewar design principles are similar to those used previously, parasitic heat flow is reduced to a new level by an optimized tension strap support system and careful attention to insulation system details. The benefit of the mechanical coolers is maximized by dewar interface design features that minimize parasitic heating and thermal impedance of the coupling. The dewar design and thermal performance analysis are discussed. Helium lifetime sensitivities and the effects of mechanical cooler failures are predicted.
Document ID
19930064658
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Nieczkoski, Stephen J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hopkins, Richard A.
(Ball Electro-Optics/Cryogenics Div. Boulder, CO, United States)
Breon, Susan R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1991
Publication Information
Publication: In: Advances in cryogenic engineering. Vol. 37B - Proceedings of the 1991 Cryogenic Engineering Conference, Univ. of Alabama, Huntsville, June 11-14, 1991 (A93-48578 20-37)
Publisher: Plenum Press
Subject Category
Engineering (General)
Accession Number
93A48655
Funding Number(s)
CONTRACT_GRANT: NAS5-31251
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available