Publications [#269046] of G. Allan Johnson

Papers Published
  1. Black, RD; Early, TA; Johnson, GA, Performance of a High-Temperature Superconducting Resonator for High-Field Imaging, Journal of Magnetic Resonance, Series A, vol. 113 no. 1 (January, 1995), pp. 74-80, Elsevier BV [doi] .

    The practicalities involved with the use of a superconducting microimaging probe are outlined so that the power and problems associated with this technology can be assessed. The nonlinearity of the transmission characteristics of this class of probe, the intrinsic limits on bandwidth, the long ring-down times, the potential for spin damping, and the difficulties of suppressing Johnson noise are all discussed. Recent refinements that have delivered a factor of 30 gain in SNR (signal-to-noise ratio) relative to copper coils at room temperature are presented. Further reductions in noise sources should yield a gain of a factor of 60 in SNR. © 1995 Academic Press, Inc.