The design of a system of adjustable superconducting plates for balancing a gradiometer

✍ Scribed by J.A. Overweg; M.J. Walter-Peters

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 408 KB
• Volume: 18
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(78)90153-4

✦ Synopsis

The gradiometer of a SQUID-system for measuring very small biomagnetic signals should be made as insensitive as possible to the much larger uniform background fields. The balance of a gradiometer can be improved considerably by modifying the effective area of the gradiometer loops by a system of small adjustable superconducting plates. This paper is intended as an aid for designing such a balancing system. We calculated the effective area of a gradiometer loop perpendicular to a rectangular or parallel to a circular plate. The paper contains graphs showing how large the plates have to be and where they must be placed.

The calculations show that for accurate balancing the distance of a plate to the wire of a loop must be large and that the plates must be as small as possible.