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Cryogen-Free Ultra-Low Temperature Cooling using a Continuous ADRThe development of a continuous adiabatic demagnetization refrigerator (CADR) has progressed to the point where we have demonstrated a 4-stage system that provides continuous cooling at 50 mK and below, while rejecting heat to a 4.2 K helium bath. Since temperature control and cycling of the ADR is fully automated, the system is simple to operate and stable. Temperature fluctuations of the cold tip are typically less than 10 microKelvin rms (at 100 mK). The ADR s cooling power of 2 1 microwatts at 100 mK is comparable to that of small dilution refrigerators, but because its efficiency is so much higher (50% of Carnot), the peak heat rejection rate is less than 10 mW. This is significant in allowing the ADR to be cooled by relatively low-power cryocoolers. In addition to commercial pulse-tube and Gifford McMahon (GM) coolers, this potentially includes small GM systems that run on 120 V power and do not need water cooling. The present focus is to design and fabricate a small dewar to house the CADR and a cryocooler, in anticipation of making a cryogen-free, low cost CADR commercially available. Performance of the prototype CADR and the complete system will be discussed.
Document ID
20040013034
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Shirron, Peter
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
DiPirro, Michael
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Jirmanus, Munir
(Janis Research Co., Inc. Wilmington, MA, United States)
Zhao, Zu-Yu
(Janis Research Co., Inc. Wilmington, MA, United States)
Shields, Bill
(Janis Research Co., Inc. Wilmington, MA, United States)
Date Acquired
August 21, 2013
Publication Date
March 14, 2003
Subject Category
Engineering (General)
Meeting Information
Meeting: Cryogenic Engineering Conference
Location: Anchorage, AK
Country: United States
Start Date: September 22, 2003
End Date: September 26, 2003
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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