Traceable precision generation and measurement of pA direct currents

TL;DR

This paper demonstrates highly accurate, traceable generation and measurement of picoampere-range direct currents using novel methods, confirming their agreement and linearity, and addressing capacitor ac-dc differences.

Contribution

It introduces a new picoammeter prototype and validates traceable pA current generation and measurement methods at unprecedented accuracy levels.

Findings

Confirmed agreement between generation and measurement methods

Validated linearity of the new picoammeter at microA/A uncertainty

Provided insights into capacitor ac-dc differences affecting current generation

Abstract

We present the comparison of results from the generation and the measurement of direct currents in the pA range, performed with traceable state-of-the-art methods at highest accuracy. The currents were generated with the capacitor charging method, and measured with the first prototype of a novel picoammeter developed at PTB. The results confirm the agreement between both methods and the 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 for current generation with the capacitor charging method.