Traceable precision generation and measurement of pA direct currents

摘要

We present the comparison of results from the generation and the measurementof direct currents in the pA range, performed with traceable state-of-the-artmethods at highest accuracy. The currents were generated with the capacitorcharging method, and measured with the first prototype of a novel picoammeterdeveloped at PTB. The results confirm the agreement between both methods andthe linearity of the new picoammeter at an uncertainty level of few microA/A.Also, they shed light on the ac-dc difference of capacitors, crucial forcurrent generation with the capacitor charging method.