Construction and test of a cryocooler-cooled low-Tc-SQUID gradiometer system

A.P. Rijpma, Hendrikus J.G. Krooshoop, M.W. Lefevere, E.P. van Leeuwen, Herman J. Holland, Bernard ten Haken, Hermanus J.M. ter Brake

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)
2 Downloads (Pure)


A cryocooler-cooled low-Tc SQUID gradiometer system was designed and constructed. It is based on a 4 K GM-cooler that is positioned several meters from the measuring head containing the SQUID sensors. The cooling power is transported by means of a circulating helium flow. Thus, there are three main components: the cooler vessel, the measuring head and the connecting flow-line. In stable operation, the SQUID and gradiometric pick-up loop are about 4.3 K. The overall heat loads to the cooler 1st and 2nd stages are estimated at 17 W and 0.3 W, respectively. The overall system noise was about 10 fT/√Hz although a number of peaks were observed in the spectrum. As an example, an adult heart beat was recorded.
Original languageUndefined
Pages (from-to)61-67
Number of pages7
Issue number1-2
Publication statusPublished - 2008


  • METIS-252478
  • Cryocoooler
  • Magnetometry
  • IR-60318

Cite this