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Use of a Pulse Tube Refrigerator for Cooling a HTS-Antenna for Magnetic Resonance Imaging

  • K. Klundt
  • C. Lienerth
  • G. Thummes
  • F. Steinmeyer
  • M. Vester
  • W. Renz
  • C. Heiden
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 43)

Abstract

We report on the first operation of a YBCO receiving antenna for magnetic resonance imaging by use of a specially designed double-inlet pulse tube refrigerator. The pressure oscillation in the cooler is generated by means of a rotary valve in combination with a 2 kW helium-compressor. To reduce noise at the cold head, the oscillating gas flow from the rotary valve is supplied to the cold head via a thin flexible tube with a length of 4 m. Optimum cooler performance is achieved with the pulse tube in vertical position (cold end facing downwards). Then, at an operating frequency of 4.6 Hz, a minimum no-load temperature of 31 K is achieved, and a net cooling power of 2 W is available at 50 K. Tilting of the pulse tube leads to enhanced heat losses through free convection of helium in the tube. By increasing the operating frequency to 8 Hz the orientation dependence of the cooler performance could be reduced. This made possible the testing of the PTR-cooled antenna in a Siemens Magnetom Open 0.2 T MRI-system with a horizontal pulse tube and with the cold block at 55 K. Compared to a standard room temperature antenna the improved signal to noise ratio that is achieved with the superconducting antenna is clearly reflected in the higher quality of MR-images taken from parts of the human body.

Keywords

Pressure Oscillation Pulse Tube Cool Performance Residual Vibration Rotary Valve 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • K. Klundt
    • 1
  • C. Lienerth
    • 1
  • G. Thummes
    • 1
  • F. Steinmeyer
    • 2
  • M. Vester
    • 2
  • W. Renz
    • 2
  • C. Heiden
    • 1
  1. 1.Institute of Applied PhysicsJustus-Liebig-UniversityGiessenGermany
  2. 2.Siemens Corporate TechnologyErlangenGermany

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