Mesoscopic SNS junctions have been studied both theoretically and experimen
tally. We have made a 64-channel whole-head SQUID magnetometer of SNS junct
ions for brain science. SNS junctions are free of low-frequency telegraph n
oise while insulator barriers of SIS tunnel junctions are electrically char
ged and discharged to generate telegraph noise. The combination of SQUIDs o
f SNS junctions and a superconducting magnetic shield for human bodies has
yielded an excellent SQUID system for brain science. Experimental data of t
he SQUID system has demonstrated that mesoscopic SNS junctions are importan
t not only theoretically but also practically. (C) 2001 Elsevier Science B.
V. All rights reserved.