The advent of low temperature superconductors in the early 1960's
converted what had been a laboratory curiosity with very limited
possibilities to a prac- tical means of fabricating electrical
components and devices with lossless con- ductors. Using liquid helium
as a coolant, the successful construction and operation of high field
strength magnet systems, alternators, motors and trans- mission lines
was announced. These developments ushered in the era of what may be
termed cryogenic power engineering and a decade later successful oper-
ating systems could be found such as the 5 T saddle magnet designed and
built in the United States by the Argonne National Laboratory and
installed on an experimental power generating facility at the High
Temperature Institute in Moscow, Russia. The field of digital computers
provided an incentive of a quite different kind to operate at cryogenic
temperatures. In this case, the objective was to ob- tain higher
switching speeds than are possible at ambient temperatures with the
critical issue being the operating characteristics of semiconductor
switches under cryogenic conditions. By 1980, cryogenic electronics was
established as another branch of electric engineering.