  Common-mode choke inductors are useful tools for resolving grounding issues
in large detector systems. Using inductive components on cryogenic
pre-amplifier boards has so far been prevented by the poor low-temperature
performance of common ferrite materialssuch as NiZn and MnZn. Recentlydeveloped
nanocrystallineand amorphous ferrite materials promise improved performance up
to the point where using magnetics at liquid mitrogen temperatures becomes
feasible. This research applies the work of Yin et al. on characterizing
ferrite materials by constructing and testing a common mode choke inductor for
use on detector pre-amplifiers for the ELT first generation instruments.
