Helium-liquefaction by cryocooler for high-field magnet cooling.

Author(s) : CHOI Y. S., PAINTER T. A., KIM D. L., et al.

Summary

Helium liquefaction by a two-stage pulse-tube cryocooler is presented. This study is motivated mainly by the authors' recent development of a closed-loop cooling system for the 21 T Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) superconducting magnets without any replenishment of the cryogen. Since the cold surface of a cryocooler is very limited, a cylindrical copper fin was thermally anchored to the first and second stage cold heads in order to extend the available heat transfer surface. A heat exchanger tube was attached on the outer surface of each cylindrical fin, and heat exchange occurs between the tube and the helium gas that is passing through the tube. The refrigeration capacity of the two-stage pulse-tube cryocooler has been measured, and, taking into account the refrigeration capacity of the cryocooler, the temperature distribution along the copper cylinder and heat exchanger tube has been calculated using a relevant heat transfer analysis. The effect of the cryocooler refrigeration capacity on the liquefaction has also been investigated.

Details

  • Original title: Helium-liquefaction by cryocooler for high-field magnet cooling.
  • Record ID : 2008-2389
  • Languages: English
  • Publication date: 2006/06/14
  • Source: Source: Proc. 14th int. Cryocooler Conf., Annapolis, MD
    655-661; fig.; 6 ref.