Practical Application of Optimal Hollow Active Auxiliary Electrode in Vertical Calculable Capacitor at NIM

After the continual investigation on the electrical compensation method for the end effect, the optimal hollow active auxiliary electrode (OHAAE) has been successfully developed and substituted for the current nosepiece in the new vertical calculable capacitor (CC) at NIM. Applying the best compensation voltage of ${U_{\text{best}}}$ obtained from the model tests, the initial measurement result by the OHAAE in the new vertical CC for reproducing the 1 pF capacitance of the same commercial capacitor agrees with that by the nosepiece in the level of ${6.0\times 10^{-9}}$ .