A Low-Noise Seven-Channel DC SQUID Magnetometer for Brain Research

Matti Kajola, Seppo Ahlfors, Antti Ahonen, Jari Hällström, Jukka Knuutila, Olli V. Lounasmaa, Claudia Tesche, Visa Vilkman

Research output: Contribution to journalArticleScientificpeer-review


The design, construction, and performance of a high-sensitivity DC SQUID magnetometer, covering a circular area of 93 mm diameter, is described. The device, now used routinely in our brain research, comprises seven asymmetric first-order gradiometers, located on a spherical surface of 125 mm radius and with the symmetry axis tilted 30° in respect to the vertical. The overall field sensitivity of the system, measured inside our magnetically shielded room, is 5 - 6 fT/√Hz, mainly caused by thermal noise in the radiation shields of the dewar.

Original languageEnglish
Pages (from-to)1555-1556
Number of pages2
JournalJapanese Journal of Applied Physics
Issue numberS3-2
Publication statusPublished - Jan 1987
MoE publication typeA1 Journal article-refereed

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    Kajola, M., Ahlfors, S., Ahonen, A., Hällström, J., Knuutila, J., Lounasmaa, O. V., Tesche, C., & Vilkman, V. (1987). A Low-Noise Seven-Channel DC SQUID Magnetometer for Brain Research. Japanese Journal of Applied Physics, 26(S3-2), 1555-1556. https://doi.org/10.7567/JJAPS.26S3.1555