Operation of a Cryogenic Current Comparator in Presence of Mechanical Vibrations

In measurements with cryogenic current comparators (CCCs), robustness against mechanical distortions is an issue. Sources of distortions are part of the experimental environment, efficient suppression is difficult. In a test setup, we intentionally applied mechanical vibrations to a CCC probe. In the 10 Hz to 3 kHz range, the frequency response of the SQUID detector's output signal was recorded for an integrative and an H-infinity-controller. When applying vibrations at fixed frequency, the stability of the SQUID's locking depended on the chosen controller, but systematic influence on the result of a 12.9 k Omega vs. 100 Omega resistance comparison was not found.