RECENT RESULTS AND FUTURE CHALLENGES FOR THE NIST CHARGED-CAPACITOR EXPERIMENT

This paper reports on recent results in some of the work toward develo ping a new capacitance standard using single electron tunneling (SET) devices, In particular, we plan on using a SET pump to charge a cryoge nic standard capacitor and measure the voltage that develops, In this paper, we summarize: 1) measurements of the ratio of two capacitors in a bridge configuration, using a SET transistor as the null detector a nd 2) stability and leakage measurements on the cryogenic capacitors, We then discuss in detail several of the possible challenges, includin g the effects of stray capacitance and line impedance, and resulting r equirements on the sensitivity of the SET null detector.