Two-stage amplifier based on a double relaxation oscillation superconducting quantum interference device
- 11 October 1999
- journal article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 75 (15), 2316-2318
- https://doi.org/10.1063/1.125001
Abstract
A low-noise single-chip two-stage superconducting quantum interference device (SQUID) system with a double relaxation oscillation SQUID as the second stage has been realized. The system was operated in a direct voltage readout mode, with a closed loop bandwidth up to 1 MHz. Operated at 4.2 K, the white flux noise measured in flux locked loop was 1.3 μΦ0/√Hz, corresponding to an energy sensitivity of ε≈27h. Owing to the large flux-to-voltage transfer of up to 3.6 mV/Φ0, the room-temperature preamplifier noise did not dominate the overall flux noise.Keywords
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