Measurements of Noise Characteristics of a dc SQUID with a Resistively Shunted Inductance

Abstract

We experimentally demonstrate that energy sensitivity of a dc superconducting quantum interference device (SQUID) with large β=2LsIo/φo is lowered by connecting a damping resistor across the loop inductance of the SQUID, where Ls is the loop inductance of the SQUID, Io is the critical current of each Josephson junction, and φo is the flux quantum. This is due to the considerable increase of the flux-to-voltage transfer function of the SQUID. © 1987 The Japan Society of Applied Physics.