Precision Picosecond-Pulse Measurements Using a High-Quality Superconducting Delay Line

A high-quality superconducting delay line now makes it possible to perform direct oscillographic measurements of the picosecond transition times of very fast electrical signals that do not furnish pretriggers. A 15-m superconducting delay line package has been assembled. The package consists of connectors, connector adapters, normally conducting input/output air lines, and a 15 m length of a miniature 1.6-mm superconducting coaxial transmission line. The package exhibits an attenuation of 0.8 dB at 10 GHz and a system 10-90 percent transition time of 18 ps. Some applications of this delay line are shown. They include the measurement of the pulse output from a mercury switch and the transient response of a traveling-wave oscilloscope.