A Josephson Voltage Calibrator

Author: Krasnopolin I.   Ugolev V.  

Publisher: MAIK Nauka/Interperiodica

ISSN: 0020-4412

Source: Instruments and Experimental Techniques, Vol.48, Iss.5, 2005-09, pp. : 611-615

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Abstract

An automatic voltage calibrator for voltages ranging from −1 V to +1 V is described. The device is based on a Josephson array with Nb-AlO x -Al-AlO x -Nb junctions. Being illuminated by microwave radiation with a frequency of 65.2 GHz, the array, in which the operating supply currents of three junction sections are set by a multichannel digital source controlled by a personal computer, generates 21 voltage values quantized with steps of 51.5, 86.6, and 138 mV. The capabilities of this device are demonstrated by studying the deviation from linearity of a seven-digit digital nanovoltmeter with a measurement uncertainty of below 1 × 10−7. By calibrating a precision Zener-diode voltage standard, it is shown that the uncertainty of this calibrator is no more than 20–50 nV at a voltage level of 1 V.