A 24-Channel Magnetometer for Brain Research

  • M. Kajola
  • S. Ahlfors
  • G. J. Ehnholm
  • J. Hällström
  • M. S. Hämäläinen
  • R. J. Ilmoniemi
  • M. Kiviranta
  • J. Knuutila
  • O. V. Lounasmaa
  • C. D. Tesche
  • V. Vilkman

Abstract

This paper describes the hardware of the 24-channel SQUID magnetometer being completed in the Low Temperature Laboratory. The overall system, including computer hardware and software, is discussed elsewhere (Hämäläinen 1989). The instrument will be used in a magnetically shielded room for brain research. We hope that this apparatus will enable us to locate current sources underlying evoked magnetic fields without moving the dewar.

Keywords

Helium Sine Fiberglass 

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References

  1. Hämäläinen, M.S., 1989, A 24-channel planar gradiometer: system design and analysis of neuromagnetic data, this volume.Google Scholar
  2. Kemppainen, P.K., and Ilmoniemi, R.J., 1989, Channel capacity of multichannel magnetometers, this volume.Google Scholar
  3. Knuutila, J., Ahonen, A.I., Hämäläinen, M.S., Ilmoniemi, R.J., Kajola, M.J., Design considerations for multichannel SQUID magnetometers, 1985, in: SQUID’85, Superconducting Quantum Interference Devices and Their Applications, H.D. Hahlbohm and H. Lübbig, eds; Walter de Gruyter, Berlin, p. 939.Google Scholar
  4. Knuutila, J., Ahlfors, S., Ahonen, A., Hällström, J., Kajola, M., Lounasmaa, O.V., Vilkman, V., and Tesche, C.D., 1987a, A large-area low-noise seven-channel dc SQUID magnetometer for brain research, Rev. Sci. Instrum., 58: 2145CrossRefGoogle Scholar
  5. Knuutila, J., Kajola, M., Mutikainen, R., Salmi, J., 1987b, Integrated planar DC-SQUID magnetometers for multichannel neuromagnetic measurements, in: Extended Abstracts of the 1987 International Superconductivity Conference, Tokyo, p. 261.Google Scholar
  6. Knuutila, J., Hämäläinen, M.S., 1989, On the spatial locating accuracy of multichannel magnetometers, this volume.Google Scholar
  7. Tesche, C.D., Brown, K.H., Callegari, A.C., Chen, M.M., Greiner, J.H., Jones, H.C., Ketchen, M.B., Kim, K.K., Kleinsasser, A.W., Notarys, H.A., Proto, G., Wang, R.H., and Yogi, T., 1985, Practical dc SQUIDs with extremely low 1/f noise, IEEE Trans. Magn., MAG-21: 1032.CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • M. Kajola
    • 1
  • S. Ahlfors
    • 1
  • G. J. Ehnholm
    • 2
  • J. Hällström
    • 1
  • M. S. Hämäläinen
    • 1
  • R. J. Ilmoniemi
    • 1
  • M. Kiviranta
    • 1
  • J. Knuutila
    • 1
  • O. V. Lounasmaa
    • 1
  • C. D. Tesche
    • 3
  • V. Vilkman
    • 1
  1. 1.Low Temperature LaboratoryHelsinki University of TechnologyEspooFinland
  2. 2.Instrumentarium Imaging LtdHelsinkiFinland
  3. 3.IBM Thomas J. Watson Research CenterYorktown HeightsUSA

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