Title :
A 64-channel DC-SQUID magnetometer system
Author :
Okajima, K. ; Komuro, Takanori ; Harada, N. ; Adachi, A. ; Ueda, M. ; Kandori, A. ; Uehara, Gen ; Kado, H.
Author_Institution :
Superconducting Sensor Lab., Chiba, Japan
fDate :
31 Oct-6 Nov 1993
Abstract :
A modular 64-channel SQUID magnetometer system has been developed for biomagnetic applications. The square-shaped double washer DC-SQUIDs are fabricated by thin film technology based on the Nb metal process. The signal is detected by a first-order planar gradiometer with counter-wound 10 mm square-shaped coils and a baseline length of 40 mm. The SQUIDs are operated in a flux locked mode. Each channel can be independently replaced without warming up of the dewar. The system is installed in a magnetically shielded room. The noise level for all 64 channels operated simultaneously is about 7 fT/√(Hz). Biomagnetic measurements have been carried out on the magnetoencephalogram (MEG) and the magnetocardiogram (MCG)
Keywords :
SQUID magnetometers; biomedical equipment; magnetocardiography; magnetoencephalography; 10 mm; 40 mm; 64-channel system; DC-SQUID magnetometer system; Nb; Nb metal process; biomagnetic applications; biomagnetic measurements; counter-wound 10 mm square-shaped coils; dewar; first-order planar gradiometer; flux locked mode; magnetically shielded room; medical instrumentation; square-shaped double washer DC-SQUIDs; thin film technology; Biomagnetics; Coils; Laser mode locking; Magnetic flux; Magnetic shielding; Niobium; Noise level; SQUID magnetometers; Signal detection; Transistors;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference, 1993., 1993 IEEE Conference Record.
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-1487-5
DOI :
10.1109/NSSMIC.1993.373538
