U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Ray Radebaugh (Assoc)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 51 - 75 of 167

Mixed Refrigerants for a Glass Capillary Micro Cryogenic Cooler

April 24, 2010
Author(s)
Mu Hong Lin, Peter E. Bradley, Marcia L. Huber, Ryan J. Lewis, Ray Radebaugh, Yung-Cheng Lee
Optimized mixed refrigerants are applied in Joule-Thomson (JT) micro cryogenic coolers (MCC) to enhance efficiency. Mixed refrigerants deliver equivalent refrigeration power with much lower pressure ratio and flow rate compared to pure nitrogen refrigerant

Development of Miniature, High Frequency Pulse Tube Cryocoolers

April 5, 2010
Author(s)
Ray Radebaugh, Isaac Garaway, Alexander Veprik
Because acoustic power density is proportional to frequency, the size of pulse tube cryocoolers for a given refrigeration power can be reduced by operating them at higher frequencies. A frequency of about 60 Hz had been considered the maximum frequency

Diagnostics and Optimization of a Miniature High Frequency Pulse Tube Cryocooler

June 28, 2009
Author(s)
Isaac Garaway, Alexander Veprik, Ray Radebaugh
A miniature, high energy density, Pulse Tube cryocooler has been developed, tested, diagnosed and optimized to provide appropriate cooling for size-limited cryogenic applications demanding fast cool down. This cryocooler, originally designed using REGEN 3

Investigation of Flow Nonuniformities in a Large 50 K Pulse Tube Cryocooler

June 28, 2009
Author(s)
Michael A. Lewis, Ryan P. Taylor, Ray Radebaugh, Isaac Garaway, Peter E. Bradley
A single stage pulse tube cryocooler was optimized to provide 50 W of net refrigeration power at 50 K when driven by a pressure oscillator that can produce up to 2.8 kW of acoustic power at 60 Hz. The cryocooler was designed with the ability to provide

Optimization Calculations for a 30 HZ, 4 K Regenerator with Helium-3 Working Fluid

June 28, 2009
Author(s)
Ray Radebaugh, Yonghua Huang, Agnes A. O'Gallagher, John M. Gary
The NIST numerical software, REGEN3.3, which incorporates both He-4 and He-3 properties, was used to calculate the losses and second law efficiencies of 4 K regenerators operating at 30 Hz. Operating parameters, such as average pressure, pressure ratio

DESIGN, FABRICATION, AND ASSEMBLY OF A HOLLOW-CORE FIBER-BASED MICRO CRYOGENIC COOLER

June 21, 2009
Author(s)
James C. Booth, Mu Hong Lin, Peter E. Bradley, H.-j Wu, Ray Radebaugh, Y.C. Lee
One of the smallest Joule Thomson (J-T) micro cryogenic coolers (MCC) utilizing a hollow-core fiberbased heat exchanger (HX) is designed, fabricated, assembled and tested. Techniques that control mask material etching are developed to fabricate a multi

Cryocoolers: State of the art and recent developments

March 31, 2009
Author(s)
Ray Radebaugh
Cryocooler performance and reliability are continually improving. Consequently, they are more and more frequently implemented by physicists in their laboratory experiments or for commercial and space applications. The five types of cryocoolers most

Crycoolers and High-T c Devices

October 16, 2008
Author(s)
Ray Radebaugh
This chapter reviews various methods and their operating principles for producing cryogenic temperatures. The use of liquid cryogens for laboratory studies of superconducting electronic devices is a common practice. That technique is mentioned briefly but

Cryogenics

October 16, 2008
Author(s)
Ray Radebaugh
This article is for publication in the Encyclopedia of Chemistry. The article gives a definition of cryogenics and describes the origin of the term and how it has been defined. Temperature scales and thermometry are discussed in relation to the absolute

Thermodynamics of Regenerative Refrigerators

October 16, 2008
Author(s)
Ray Radebaugh
Regeneration refrigerators operate with oscillating pressures and flows. Such refrigerators include the Stirling, Gifford-McMahon, and pulse tube refrigerators. This book chapter introduces the thermodynamics for analyzing such refrigeration systems. The

Calculated Performance of Low-Porosity Regenerators at 4 K with He-4 and He-3

June 9, 2008
Author(s)
Ray Radebaugh, Yonghua Huang, Agnes A. O'Gallagher, John M. Gary
Previously we have shown that the lower volumetric heat capacity and more ideal behavior of helium-3 compared with helium-4 at 4 K results in an improved performance for packed sphere regenerators operating with helium-3 between 4 K and about 20 K. In this

Pulse Tube Cryocooler for Rapid Cooldown of A Superconducting Magnet

June 9, 2008
Author(s)
Michael A. Lewis, Ryan P. Taylor, Peter E. Bradley, Isaac Garaway, Ray Radebaugh
A single-stage pulse tube cryocooler was designed to provide rapid cooldown of a high temperature superconducting (HTS) magnet that is part of a gyrotron required for the generation of a high-power mm-wave (95 GHz) beams. These beams are used in the