Using SQUIDs to Detect Charge in Cryogenic Germanium Detectors
This paper describes an impedance matching network which allows charge impulses to be measured by a SQUID amplifier with an RMS charge noise of less than 100 e, assuming the SQUID amplifier has a current noise of 2 pA/√Hz, and the current pulse has a duration of about 1 μs or shorter. The component values are provided for an example system which has an RMS charge noise of 91 e, assuming all dissipative circuit elements are cooled to a temperature of 100 mK.
Moffatt, R. A., Cabrera, B., Kadribasic, F., Pyle, M., Wesenberg, D., Yen, J. J., & Young, B. A. (2012). Using SQUIDs to Detect Charge in Cryogenic Germanium Detectors. Journal of Low Temperature Physics, 167(5), 638–644. https://doi.org/10.1007/s10909-012-0593-8