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Two-hole bulk high Tc squid electronic gradiometer for magnetocardiography in unshielded space

✍ Scribed by Y.A. Tavrin; Y. Xu; A.I. Braginski; C. Heiden; A.S. Linnik; V.A. Pavliuk; V.V. Schapovalenko


Publisher
Elsevier Science
Year
1993
Tongue
English
Weight
442 KB
Volume
33
Category
Article
ISSN
0011-2275

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✦ Synopsis


A first order electronic gradiometer has been developed to operate in liquid nitrogen. The use of two-hole bulk Yga2Cu30 7 RF SQUIDs permitted optimization of the characteristic SQUID parameter, #L = 1, without compromising the noise performance. Additional bulk flux concentrators made it possible to attain a field/flux transformation coefficient of 8 x 10 -1° T (1)ol. A mechanical fixture for electronic balancing provided a common mode suppression of 103. In an unshielded environment, the balanced system had a peak-to-peak noise amplitude of < 10 pT within a signal bandwidth of 2-30 Hz. Human heart beat signals (the QRS peak) could be recorded in these conditions.