The 2018 Helmholtz prize for “Precision Measurements in Applied Measurement Technology” has been awarded to e-SI-Amp partners PTB for work on improvements in the accurate measurement and generation of small currents. Prizes are awarded by the Helmholtz Foundation (Germany) for outstanding scientific and technological research in the field of “Precision Measurement in Physics, Chemistry and… Read More

Secondary/transfer standards used to capture a calibrated quantity (e.g. resistance) need to be stable, as this is something that can easily limit the reliability of a calibration (rather than the source uncertainty for instance). However, what exactly limits the stability, e.g. aging or thermal/mechanical stresses is a complicated question. The Ultrastable Low-Noise Current Amplifier (ULCA)… Read More

Electron pumps are typically fabricated using lithographic masks defined by electron beams. This process has the high resolution and flexibility required to fabricate prototype single electron devices in Si or GaAs systems, but is relatively slow and not compatible with techniques used for larger scale production of devices, or for integration into a larger device… Read More

Tunable barrier pumps in semiconductor devices can drive a clock-controlled pump current and thus represent a prototype quantum current standard. A problem facing any practical electron pumping scheme is that accurate pumping cannot take place at arbitrarily high frequency. In practice this limits accurate pumping to a frequency of order 1 GHz. Scientists at KRISS,… Read More

While lithographically engineered charge traps can be used for single-electron transport, ‘accidental’ single-electron trapping behaviour can also occur, particularly in very small semiconductor devices. This can be a nuisance in some circumstances, but might also provide useful access to single-electron transistor (SET) effects in simple devices. Researchers at e-SI-Amp partner University of Southampton (UoS) and National… Read More

The NPL single-electron group, in collaboration with the University of New South Wales (UNSW), Australia, has recently measured the current from a silicon single electron pump with an uncertainty of just 0.27 parts per million (ppm) [1]. Previous measurements of a silicon pump measured by NPL and NTT, Japan were limited to an accuracy of… Read More

Dr. Stephen Giblin from e-SI-Amp partner NPL was awarded the best paper award at the NCSLI workshop and symposium (August 2017, Maryland, USA).  NCSL International (NCSLI) (from the founding name “National Conference of Standards Laboratories”) is a global, non-profit organization whose membership is open to any organization with an interest in metrology (the science of measurement) and its application in research,… Read More

e-SI-Amp partner VTT (Finland), PTB (Germany) and e-SI-Amp stakeholder Tampere University of Technology (TUT, Finland) have been improving the measurement techniques and traceability of small electric currents in the Single Charge Aerosol Reference (SCAR) located at TUT. Aerosol particles may play an important role in global climate change. Fine and ultrafine particles have also found… Read More

A growing range of medical treatments and diagnostic procedures use radioactive sources. The strength of these sources is often measured using ionisation chambers whose output is an electrical current in the range from picoamperes (10-12 A) to microamperes (10-6 A). Robust, traceable calibration of the electrical current readout is vital for validating the stability and… Read More

Scientists at e-SI-Amp partner Physikalisch-Technische Bundesanstalt (PTB) have developed a stable current amplifier for the sub-picoampere measurement range. The low noise and stability makes direct current measurements with uncertainties of less than 10 attoamperes (1 attoampere = 10-18 A) readily achievable. The “ultrastable low-noise current amplifier” (ULCA) enables traceable measurement and generation of small currents… Read More