Effect of RF interference on characteristics of DC SQUID system

Abstract

The effects of RF interference on the characteristics of DC superconducting quantum interference devices (SQUIDs) are investigated. The noise of a DC SQUID gradiometer radiating an RF field with a frequency between 100 kHz and 80 MHz was measured. As the RF field strength intensified, the white noise level increased and the cut-off frequency was lowered. The flux-voltage transfer function (dV/d Phi ) of the DC SQUID was influenced strongly by the RF field. dV/d Phi decreased as the RF field intensified. Based on these results, the level of the electromagnetic environment at which the operation of the SQUID system would not be affected was found. The effect of high-frequency magnetic field on the flux to voltage transfer function was investigated by computer simulation using a simple resistively shunted junction (RSJ) model.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>