What's New!
Liquid Cryogen Free Superconducting Magnet System
Release Date: September 16, 1999
Introduction
Cryomagnetics, Incorporated, of Oak Ridge, Tennessee, announces the successful test of a 9
Tesla, cryogen-free superconducting magnet system based on a pulse-tube refrigerator (work
performed under NIH SBIR Grant # 1 R43 GM59564-01). The system utilizes a recently
developed two-stage 4K pulse-tube refrigerator developed by Dr. Chao Wang of Cryomech,
Incorporated, Syracuse, New York. The cryocooler is used to cool an intermediate thermal
shield and HTS current leads to approximately 50K and the NbTi-based superconducting
magnet to 4K. No liquid cryogens are required. This is believed to be the first commercial
application of a pulse-tube refrigerator for direct cooling of a superconducting magnet.
System Details
The system has a horizontal 32mm clear room temperature bore diameter through the high
field region. The cryostat is a compact 17" outside diameter by 12" length. The
refrigerator access tube is located on top of the system. The magnet generates a magnetic
field of up to 9T with 0.1% homogeneity over a 10mm diameter volume. The system utilizes
Bi-2223 based HTS current leads that were also developed by Cryomagnetics. Cool-down time
from room temperature to operating temperature is approximately 14 hours. The magnet was
charged in less than one hour. After an intentional quench at 9.2T, the system recovered
in temperature in approximately 3 hours.
Advancements over Conventional Liquid Cryogen Free Systems
- Low Vibration. The new pulse-tube has no moving cold parts. Common cryo-refrigerator
systems rely on a moving displacer that transmits vibration through the cold head to the
superconducting magnet system. Vibration-sensitive experiments cannot be performed with
conventional cryocoolers.
- Low Maintenance. No moving displacers means no cold seals to maintain.
- Low Noise. Lack of moving parts in the cold head make for a very quiet system.
- Low Cost. Due to its simplicity, the pulse-tube can be manufactured for less cost than
common cryo-refrigeration systems.
Applications
Any application where low-cost and low-vibration are important issues. Cryomagnetics is a
custom design superconducting magnet manufacturer, so it is likely a pulse-tube based
superconducting magnet system can be designed to individual researcher specifications. The
pulse-tube cryo-refrigerator is a versatile instrument that can be incorporated into many
conventional systems. For example, the pulse-tube system can be used in liquid helium
based systems to reduce or eliminate liquid helium boiloff.
Cryomech is developing more powerful pulse-tube cryo-refrigerator systems to address
the needs of the future.
Previous What's New Pages:
New LHe and LN2 Point Monitors!
Scientific American Articles!
New Temperature and Gauss Meters!
New LabVIEW® Drivers Available!
New High Field Magnet Record!
New Liquid Cryogen Monitor!
sales@cryomagnetics.com
Please contact us for more information!
1006 Alvin Weinberg Drive
Oak Ridge, Tennessee 37830
USA
Phone: (865) 482-9551
Fax: (865) 483-1253
All information subject to change due to design improvements.