Abstract
A light weight and low-cost active magnetic shield system is proposed for a single channel SQUID-based magnetocardiography system equipped for operating at liquid nitrogen temperature without passive magnetic shield. The developed active shield, using coils around the sensors, is a two-stage magnetic shielding system, each stage of which has been designed to compensate different frequency and dynamic ranges. The sensor part contains two high-Tc rf-SQUID magnetometers, capable of working stably under earth magnetic field, placed in an axial gradiometric arrangement with a baseline of 10 cm. The active shield setup is driven using two correlated proportional-integral-derivative closed loop systems. In the designed system, the coils are in the vicinity of the SQUIDs, resulting in coupling the coils to the SQUIDs as well as to the resonators. Hence, the impedance of the coils along with the phase of the feedback current is affected based on the configuration. In this paper, investigation of the shielding performance of our bi-stage magnetic shield as the active compensation, fed by the optimal feedback control system with all the above considerations, is reported. Using the designed shielding system, the disturbing magnetic signals could be attenuated such that the pico-Tesla signals could be obtained.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.