High-temperature superconductors have distinct advantages compared to conventional conductors. Below their critical temperature, superconductors have immeasurably low ohmic losses. To maintain the superconducting state, superconductors require constant cooling. This study aims at identifying the environmental impacts of the application of superconductors in future grid technologies such as superconducting power cables.
This work presents three advances to scale SNSPDs from few-pixel devices to large detector arrays: atomic layer deposition for the fabrication of uniform superconducting niobium nitride films of few-nanometer thickness, a frequency-multiplexing scheme to operate multiple detectors with a reduced number of lines, and the integration of SNSPDs with free-form polymer structures to achieve efficient optical coupling onto the active area of the detectors.
This book, in essence the proceedings of a NATO Advanced Study Institute with the same title, is designed to provide in-depth coverage of many, but not all, of the major current applications of superconductivity, and of many that still are being developed. It will be of value to scientists and engineers who have interests in the research and production aspects of the technology, as well as in the applications themselves. The ftrst three chapters (by Clarke, Vrba and Wikswo) are devoted to an understanding of the principles, fabrication and uses of SQUID magnetometers and gradiometers, with the greatest emphasis on biomagnetism and nondestructive evaluation (NDE). For the most part, traditional low-temperature superconductor (LTS) SQUIDs are used, but particularly for NDE, high-temperature superconductor (HTS) SQUIDs are proving useful and often more convenient. The succeeding three chapters (by Przybysz, Likharev and Chaloupka) cover broader aspects of superconducting electronics. The ftrst two of these deal primarily with digital L TS circuits, while the third discusses in great detail passive component applications using HTS materials. Currently, HTS ftlters are undergoing intense J3-site testing at cellular telephone base stations. While it is clear that HTS ftlters outperform conventional ftlters in reducing signal loss and allowing for more channels in a given bandwidth, it isn't yet certain that the cellular telephone industry sees sufficient economic beneftts to make a ftrm decision to use HTS ftlters universally in its systems. If this application is generally adapted, the market for these ftlters should be quite large.
A design process for HTS DC cables was developed for high current applications. Based on the design process, a 35 kA HTS DC cable demonstrator was developed. The superconducting elements of the demonstrator were manufactured and tested individually at 77 K. Afterwards, the demonstrator cable was assembled and tested at 77 K. The assembled demonstrator successfully reached 35 kA at 77 K and self field conditions.
Accessible to graduate students and experimental physicists, this volume emphasizes physical arguments and minimizes theoretical formalism. Topics include the Bardeen-Cooper-Schrieffer and Ginzburg-Landau theories, magnetic properties of classic type II superconductors, the Josephson effect, fluctuation effects in classic superconductors, high-temperature superconductors, and nonequilibrium superconductivity. 109 figures. 1996 edition.
