Interference characterization of cryocoolers for a high-Tc SQUID-based fetal heart monitor

A.P. Rijpma, M.R. Bangma, H.A. Reincke, E. de Vries, H.J. Holland, H.J.M. ter Brake, H. Rogalla

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic


    The FHARMON-project at the University of Twente aims at a high-Tc SQUID based fetal heart monitor for use in standard clinical environments. Besides the suppression of environmental magnetic noise, the cooling of this fetal heart monitor is an important issue. For maximum flexibility, we intend to apply a closed-cycle cryocooler instead of a liquid nitrogen cryostat. Because of the extreme sensitivity of SQUID magnetometers, the interference caused by the cryocooler is of major importance. This concerns electromagnetic interference (EMI), mechanical vibrations and temperature fluctuations. We have developed measuring techniques to characterize coolers in this respect. The characterization procedures were tested on a Signaal USFA 7058 Stirling cooler and a Leybold RGD210 GM-cooler. In the paper the measuring techniques are described along with interference characteristics of an APD Cryotiger and a Ricor/AirLiquide K535 Stirling cooler. Also, the impact on the design of the fetal heart monitor is considered.
    Original languageEnglish
    Title of host publicationCryocoolers 11
    EditorsR.G. Ross Jr.
    Place of PublicationBoston, MA
    Number of pages10
    ISBN (Electronic)978-0-306-47112-4
    ISBN (Print)978-0-306-46567-3
    Publication statusPublished - 20 Jun 2001
    Event11th International Cryocooler Conference, Cryocoolers-11 2000 - Keystone, United States
    Duration: 20 Jun 200022 Jun 2000
    Conference number: 11


    Conference11th International Cryocooler Conference, Cryocoolers-11 2000
    Abbreviated titleCryocoolers
    Country/TerritoryUnited States


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