Electrometer Calibration With Sub-Part-Per-Million Uncertainty

Abstract

We performed calibrations of four different commercial picoammeters using the ultrastable low-noise current amplifier (ULCA) as a calibrator current source operated in the range between 1 fA and 1 µA. The results allow the comprehensive characterization of the devices under test regarding noise, settling, and burden voltage behavior as well as stability of the gain factor, and confirm the performance of the ULCA for use as small-current calibrator standard. Also, we present a further advanced setup for the calibration of transimpedance amplifiers. Accuracy limits for the best electrometer calibrations in the current range between 1 fA and 1 µA and possible implications on corresponding calibration and measurement capabilities are discussed.

Quantum mechanical current-to-voltage conversion with quantum Hall resistance array

“…In conclusion, we have experimentally demonstrated a current-to-voltage conversion with the The CMC values of PTB registered in the BIPM are plotted by black circles for comparison. Square, pentagon, and diamond symbols depict the measurement uncertainties for the ULCA (PTB) [11], the measurement of single electron pump with a timely calibrated resistor (NPL) [9], and the programmable quantum mechanical current generator (LNE) [8], respectively.…”

“…[23]. Square, pentagon, and diamond symbols depict the measurement uncertainties for the ULCA (PTB) [11], the measurement of single electron pump with a timely calibrated resistor (NPL) [9], and the programmable quantum mechanical current generator (LNE) [8], respectively. The x-axis is the nominal current value driven in the circuit.…”

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

“…Additionally, the SEP generation of quantized arbitrary current wave forms by modulation of the pumping frequency has been experimentally demonstrated and might prove useful for low‐current ac calibrations . However, meanwhile alternative concepts for small‐current dc calibrations in the range between fA and µA are available which offer significant advantages regarding laboratory practicability and scalability, as discussed in detail, and, picked up again further below in this article.…”

“…For instance, in high‐accuracy current measurements on SEP devices, a current of 100 pA sourced by an SEP was measured with a relative standard uncertainty of 0.16 µA A −1 within less than one day of integration time . Reaching this accuracy record was mainly enabled by the extremely high gain stability of the ULCA: upon calibration, A TR typically undergoes variations less than 0.1 µΩ Ω −1 within one day …”

“…One prominent example from the recent time is small‐current methods based on the ULCA. In combination with a voltmeter calibrated traceable to the Josephson constant (or, respectively, the values for e and h exactly defined in the revised SI), this versatile and easy‐to‐use room‐temperature instrument can be applied as electrometer, but also as current generator for the measurement of currents and the calibration of instruments up to the µA range, and with unparalleled accuracy . Important to note is that the ULCA is calibrated traceable to the von‐Klitzing constant (respectively, to e and h ) by means of a CCC at currents of the order of 10 nA, and that traceability of currents ranging between fA and µA is enabled by the linearity of the ULCA within its dynamic range.…”