High-resolution measurement by a high-Tc superconductor sampler

We measured a signal current waveform by using a high-T-c superconductor (HTS) sampler with a l-ps delay between every sampling point. The maximum time differential obtained in the measured waveform was 12 mu A/ps with a 2.5-mu A current sensitivity at 25 K. This result guarantees that the sampler is able to measure current waveforms correctly when their maximum time differential is less than 12 mu A/ps. The superior temporal response was achieved by using high-speed single-fluxquantum pulses generated in the HTS circuit. A unique feature of the sampler is that it directly measures the current with picosecond and microampere resolutions, Measurement of current flowing through wiring in a semiconductor large-scale integrated circuits is a promising application for the HTS sampler.