Abstract
Progress toward the development of a 28-multichannel system for neuromagnetic measurements is described. A novel hybrid design consisting of 16 first-order axial gradiometers and 12 first-order planar gradiometers was chosen, which optimize the use of the available cylindrical volume of the dewar tail. This configuration maintains the symmetry of the detected pattern with respect to rotation of a biomagnetic source located under the center of the array and features a localization power considerably better than an array of all first-order planar gradiometers. The detecting array permits simultaneous magnitude measurements over a circular scalp region of 16-cm diameter. The magnetic sensors used are Nb/PbAuIn DC SQUIDs fabricated at IBM. The devices incorporate resonant damping resistors shunting the inductance, resulting in smooth flux-voltage characteristics and, consequently, very low noise figures in a flux-locked loop configuration. A simple and low-cost electronic system has been designed and fabricated for the DC SQUID sensors, consisting of a compact head mounted on top of the cryogenic probe and a control unit where all the DC remote controls are performed. The dynamic range of 10/sup 7/ square root Hz and the bandwidth of 50 kHz are specifically designed to work in multichannel DC SQUID instrumentation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
