Some activities of the Electrical Standards Group

摘要

The Electrical Standards Group maintains primary standards, per-forms calibrations, provides technical consultation, and maintains and upgrades its calibration facilities. The program covers the electrical standards of voltage, resistance, capacitance, inductance, dc voltage ratio, low frequency ac voltage ratio, ac/dc difference, and ac resistance; and voltage, impedance, attenuation, power and noise at RF, and microwave frequencies up to 110 GHz. The program disseminates values of these standards through a comprehensive calibration service and provides technical support for the Institute's Calibration Laboratory Assessment Service (CLAS) activities. A client list of over 120 contacts is maintained. These activities impact on most technical, manufacturing, transportation, military and utility sectors.'SET' Current Standard: Single Electron Tunneling (SET) devices are being fabricated and tested to study their possible application as an electrical current standard. Single electron tunneling has recently been observed in very small metallic tunnel junctions and in some gated semiconductor devices. This effect only becomes apparent in very small structures (approx 100 nanometers) and at low temperatures, where the energy related to the transfer of a single electron can be the dominant energy scale in the system. Gated circuits with two weak links, also known as electrometers or transistors, are sufficient to observe the charging effect corresponding to a single electron but more complex devices, referred to as "turnstiles" and "single electron pumps", are required to accurately control the transfer of single electrons. In turnstiles and pumps, a signal of frequency, I, produces a current I = ef, making them candidates as an electrical current standard.