Browse Prior Art Database

High Spatial Resolution Magnetometer Head for Commercially Available Squids

IP.com Disclosure Number: IPCOM000043897D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Jaycox, JM: AUTHOR [+2]

Abstract

Commercial SQUIDs (Superconducting Quantum Interference Device) are designed with input coils having inductances which are intended to match well to most experiments for which the SQUIDs are used. The inductance of the input coil is typically low, of the order of two microhenries, and should be matched to the SQUID. A scheme for effectively matching a conventional RF SQUID to a low inductance pickup loop is described. This matching allows the use of RF SQUIDs for certain applications, which is advantageous due to the sophisticated linear readout electronics which are available for use with RF SQUIDs. Fig. 1 diagrams the input circuit of a SQUID magnetometer, the SQUID 10 being comprised of a Josephson device J in a superconducting loop 12.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

High Spatial Resolution Magnetometer Head for Commercially Available Squids

Commercial SQUIDs (Superconducting Quantum Interference Device) are designed with input coils having inductances which are intended to match well to most experiments for which the SQUIDs are used. The inductance of the input coil is typically low, of the order of two microhenries, and should be matched to the SQUID. A scheme for effectively matching a conventional RF SQUID to a low inductance pickup loop is described. This matching allows the use of RF SQUIDs for certain applications, which is advantageous due to the sophisticated linear readout electronics which are available for use with RF SQUIDs. Fig. 1 diagrams the input circuit of a SQUID magnetometer, the SQUID 10 being comprised of a Josephson device J in a superconducting loop 12. The SQUID input coil 14 has an inductance Li while the magnetometer pickup coil 16 has an inductance Lu . There is a parasitic inductance Lp associated with the circuitry connecting the pickup coil and the input coil. A flux Wd applied to the pickup coil induces a circulating current Wi in the input coil which induces a flux in the SQUID that is then detected. For maximum sensitivity, Lu is approximately equal to Li and Lt is much less than Li . In order to make a magnetometer with a spacial resolution of approximately 1 mil, a pickup coil having dimensions approximately 1 mil is needed. In order to match a commercial SQUID having Li of approximately 2 microhenries would require an unreasonab...