Application of conserved thermal-noise energy model to damped resonant behavior in cryogenic current comparators

Measurements of the resonant behavior of a cryogenic current comparator (CCC) under a range of damping conditions have been made. A model of conserved thermal-noise energy in resonant systems has been applied showing that, regardless of the value of the damping resistor, the energy stored in the resonance is constant. This finding is presented in the context of the design of high turn CCCs for use in the measurement of small currents where there is an increasing requirement to understand and reduce noise. Various damping methods for CCCs are described and experimental results compared with the theory.