All-planar SQUIDs and pickup coils for combined MEG and MRI

Juho Luomahaara (Corresponding Author), P.T. Vesanen, J. Penttilä, J.O. Nieminen, J. Dabek, J. Simola, Mikko Kiviranta, Leif Grönberg, C.J. Zevenhoven, R.J. Ilmoniemi, Juha Hassel

    Research output: Contribution to journalArticleScientificpeer-review

    25 Citations (Scopus)


    Flux trapping and random flux movement are common problems in superconducting thin-film devices. Ultrasensitive magnetic field sensors based on superconducting quantum interference devices (SQUIDs) coupled to large pickup coils are especially vulnerable to strong external fields. The issue has become particularly relevant with the introduction of SQUID-based ultra-low-field (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) techniques. In this paper, we study the constraints of thin-film-based magnetometers and gradiometers as exposed to magnetic field sequences of ULF MRI. In particular, we address issues such as response recovery, transient noise, magnetization and behaviour under shielded room conditions after prepolarization. As a result, we demonstrate sensors that are suitable for a combined multi-channel magnetoencephalography (MEG) and MRI imaging system.
    Original languageEnglish
    Article number075020
    Number of pages7
    JournalSuperconductor Science and Technology
    Issue number7
    Publication statusPublished - 2011
    MoE publication typeA1 Journal article-refereed


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