Traceability of photocurrent measurements to electrical standards

Abstract

In detector output-signal measurements, where the measurement uncertainty critically impacts the total uncertainty of a detector-based radiometric scale realization, traceability of the photocurrent measurement to SI traceable electrical standards is needed. A reference photocurrent-to-voltage conversion scale has been developed and described here. The new standard has internal reference resistors for all signal-gain selections to decrease noise pickup of traditionally used external reference resistors. The internal resistors were calibrated by the NIST Quantum Electrical Metrology Division against standard resistors. Using the substitution method, the reference photocurrent-to-voltage conversion scale was transferred from the converter standard to other converters up to a maximum signal-gain of 1010 V/A with an expanded uncertainty of 0.013% (k=2). The DC conversion scale was extended to AC mode signal-gain calibrations where the photocurrent measurement uncertainty is 0.05% (k-2).