Community Research and Development Information Service - CORDIS

Programmable Josephson voltage standards for AC and DC metrology - ProVolt

Various kinds of Josephson series arrays for operation at microwave frequencies from 10GHz to 70GHz were fabricated using different kinds of technologies. As a result of new technological developments, the original work plan had been supplemented by including the fabrication of SINIS series arrays. This new kind of junctions enabled the fabrication of 1V arrays already after a project term of one year, which was faster than had been originally planned.

Different kinds of electronic equipment and bias systems for the different versions of programmable voltage standards have been developed. Some cryoprobes have been constructed. Series arrays and instrumentations were delivered to the partners. Characterization and testing of the arrays and of the associated electronics were carried out by several partners. They found that series arrays divided into binary segments are an excellent, programmable DC voltage source. On the other hand, further developments and further progress will be necessary before these arrays can be used for AC synthesis.

First tests of the completely new high-speed electronics for the bipolar voltage source were very promising. Further tests and measurements will be carried out. Precision measurements and direct comparisons showed good agreement between conventional SIS and SINIS arrays at both, the milli-volt and the volt level. One of the partners has additionally concentrated on amplifiers for AC-DC transfer at low voltages. The work has benefited from the results, too, as these developments have supported the planned aims by measurements at low voltages and low frequencies.

As had been planned, the partners have developed the basis for programmable voltage standards to be used as a quantum voltmeter. The results will help to further harmonize the European system of precise, reproducible and repeatable measurements.

Conclusions:
-The ProVolt project partners finally succeeded in establishing the basics for the development of a programmable Josephson voltage standard for precise DC and AC voltage metrology in Europe. Besides these technological developments, the project has improved the skill of all participating laboratories to a high level in this domain and strengthened the links between European national metrology institutes.

-Technology, electronics and measurement techniques have been studied towards the development of new types of Josephson voltage standard arrays, with high intrinsic reference voltage stability and the possibility for rapid selection of certain reference voltages, including the option of synthesizing AC voltages. This will lead to the development of a new type of voltage standards for industrial and national metrology institutes.

The results of the ProVolt project, forming a quantum basis for DC and AC voltage metrology, will help to harmonize the European system of precise, reproducible and repeatable measurements. Thus the European test and measurement facilities will experience a distinct improvement, and the competitiveness of the European industry will be further strengthened.

Related information

Reported by

PHYSIKALISCH-TECHNISCHE BUNDESANSTALT (PTB)
BUNDESALLEE 100
38116 BRAUNSCHWEIG
Germany
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