Construction and tests of a high-Tc SQUID-based heart scanner cooled by small Stirling cryocoolers

C.J.H.A. Blom, Hermanus J.M. ter Brake, Herman J. Holland, A.P. Rijpma, Horst Rogalla

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A heart scanner that can be equipped with up to 25 high-Tc SQUID magnetometers was designed at the University of Twente. In this design the mechanical cooler interference is reduced by operating two coolers in counterphase. The magnetic cooler interference diminished by positioning the coolers and the SQUIDs in a coplanar arrangement, and by separating the SQUIDs from the cold tips of the cryocoolers with a solid conducting thermal interface. In the present paper the construction of this cryogen-free high-Tc SQUID system is described and test results are presented. A SQUID plate temperature of 60 K was realized in about 2 hours. The corresponding heat load to the coolers is roughly 0.9 W. With a preliminary magnetic shield around the compressors a noise level of 0.6 pT/√Hz was measured in the frequency band 10 to 100 Hz and magnetocardiograms were recorded inside a magnetically shielded room. A further reduction of the noise level is expected after optimizing the mumetal shielding of the compressors.
Original languageUndefined
Title of host publicationProceedings International Cryocooler Conference, Cryocoolers 10, eds. R.G. Ross jr.
EditorsR.G. Ross
Place of PublicationMonterey, Californie
Number of pages10
Publication statusPublished - 23 Jun 1999
Event10th International Cryocooler Conference, Cryocoolers-10 1998 - Monterey, United States
Duration: 26 May 199828 May 1998
Conference number: 10


Conference10th International Cryocooler Conference, Cryocoolers-10 1998
Abbreviated titleCryocoolers
Country/TerritoryUnited States


  • METIS-130404
  • IR-60934

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