The ratio error of the overlapped-tube cryegenic current comparator

Analytic expressions for the ratio uncertainty of the overlapped-tube cryogenic current comparator are derived for dimensioning the overlapped-tube comparator. Theoretical predictions agree reasonably well with experimental observations by H. Ramin (Arch. Elektrotech., vol.58, p.53, 1976). The construction of a very sensitive cryogenic current comparator and the possibility of minimizing the ratio uncertainty by reducing the size of the detection coil are also discussed.<&gt