Dc - Squid Sensor System for Multichannel Neuromagnetometry
نویسنده
چکیده
Various DC-SQUID sensor configurations were developed for use in our 19-channel neuromagnetometer. Apart from the standard type, resistively and inductively shunted SQUIDs were made, allowing for a large screening factor p (>l). In this way signal coupling from the pick-up coil to the SQUID is facilitated and capacitive coupling between the input coil and the SQUID washer can be decreased. The number of tums of the input coil is decreased further by allowing for an inductance mismatch in the input circuit. Although theoretically both measures give rise to an increased field noise of the sensor, they may lead to a reduction of the excess noise and the noise balance may become positive.
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