MEASUREMENT OF VERY HIGH LEAKAGE RESISTANCES IN 1 PF CRYOGENIC CAPACITORS USING A SET DETECTOR

摘要

1 pF cryogenic capacitors form an important element of a future measurement system for the small currents generated by single electron pumps [1]. This application sets a stringent requirement on the minimum leakage resistance of the cryogenic capacitor, at 6X10~(19)OMEGA. In this work, a Single Electron Transistor (SET) was used as a sensitive charge detector to evaluate the leakage resistance of two types of cryogenic capacitor. These resistances were found to be 3X10~(16)OMEGA for fused-quartz dielectric and >10~(18)OMEGA for ~(3)He-~(4)He mixture dielectric capacitors.