### Design of the Kibble balance for the QEMMS

August 22, 2020

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Displaying 1 - 25 of 113

August 22, 2020

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, , , , , ,

August 22, 2020

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, , , , , ,

After the recent redefinition of the International System of Units (SI), torque no longer needs to be traceable to a calibrated mass in a gravitational field suspended from a known lever arm and disseminated through a chain of torque transducers.An SI

November 28, 2017

Author(s)

, Harald Bosse, Horst Kunzmann, , Ian Robinson, Michael de Podesta, Paul Shore, Paul Morantz

All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an approach which had already been implemented for the redefinition of the unit of length, the metre

July 28, 2017

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, , , , , , ,

Researchers at the National Institute of Standards and Technology(NIST) estimate the value of the Planck constant as h = 6.62606994(10) x 10^-34 Js, hence with relative standard uncertainty 15.3 x 10^-9. This measurement result is based on over 17,000

September 28, 2016

Author(s)

, , , Shisong Lee, , , ,

Using a watt balance and a frequency comb, a mass-energy equivalence is derived. The watt balance compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct

September 28, 2016

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, , , , , , , ,

Although mass is typically defined within the International System of Units (SI) at the Kilogram level, the pending redefinition of the SI provides an opportunity to realize mass at any scale using electrical metrology. We propose the use of an

July 26, 2016

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, , , , , , , ,

Measurements of the Planck constant with watt balances using 1 kg masses have achieved relative standard uncertainties below 2 x 10-8. Having established a metrological link between the kilogram and this fundamental constant of nature, a redefinition of

July 10, 2016

Author(s)

, , , , ,

In the past four years, we have constructed a new watt balance at the National Institute of Standards and Technology (NIST), with the goal to realize the unit of mass after the redefinition of the International System of Units, expected to occur in 2018

June 21, 2016

Author(s)

, , , , , , , Shisong Li

A precise instrument, called a watt balance, compares mechanical power measured in terms of the meter, the second and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck

February 10, 2016

Author(s)

, Shisong Li, , , ,

A watt balance is a precision apparatus for the measurement of the Planck constant that has been proposed as a primary method for realizing the unit of mass in a revised International System of Units. In contrast to an ampere balance, which was

October 20, 2015

Author(s)

, , , , , , , , Xiang Zhang

A redefinition of our system of units, the SI, is currently being discussed and its implementation is expected in 2018. With the redefinition, the current base units will no longer be required and all units henceforth will be based upon fixed values of

September 8, 2015

Author(s)

, , , ,

We present an opto-mechanical accelerometer device with high dynamic range, high bandwidth and readout noise levels exceeding 10 μg/√Hz . The straightforward assembly and small cost of our device make it a prime candidate to perform on-site calibrations

July 8, 2015

Author(s)

, , , , , ,

Compact optical cavities can be combined with motion sensors to yield unprecedented resolution and SI-traceability in areas such as acceleration sensing and atomic force microscopy AFM, among others. We have incorporated Fabry-Perot fiber-optic micro

June 1, 2015

Author(s)

, , , ,

As most readers are probably at least vaguely aware, it is likely that the SI system of units will be redefied in 2018. This redefinition would fundamentally change the logical structure of the SI, with one result being a substantial change in how mass is

March 31, 2015

Author(s)

, , , , , , ,

In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, similar to a mass comparator, the gravitational force of an unknown mass is compensated by an

January 21, 2015

Author(s)

, Eric J. Leaman, , , , , ,

A new watt balance is being constructed at the National Institute of Standards and Technology in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. The total

December 22, 2014

Author(s)

,

We present instrumentation and methodology for simultaneously measuring force and displacement at the atomic scale at 4 K. The technique, which uses a macroscopic cantilever as a force sensor and high-resolution, high-stability fiber-optic interferometers

December 10, 2014

Author(s)

, , , ,

We report the development of an ultrasensitive optomechanical sensor designed to improve the accuracy and precision of force measurements with atomic force microscopy. The sensors achieve quality factors of 4.3x10^6 (a 100-fold improvement over quartz

November 9, 2014

Author(s)

, , , , , , , ,

NIST recently used a watt balance instrument known as NIST-3 to measure the Planck constant in terms of IPK with a relative uncertainty of approximately 45 parts in 10e9. Along the way to this new NIST value of h, the instrument was also employed to

November 9, 2014

Author(s)

, , , , ,

A watt balance is an electromagnetic force balancing instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key components. Our group at the National Institute of Standards and Technology is currently building a next

August 24, 2014

Author(s)

, , , Radek Smid, Hugo Zuniga Calvo, , ,

This paper reports progress on the NIST effort to develop a new calculable capacitor, focusing on improvement of the guard electrode motion control as well as issues associated with the overall electrode alignment. Design of a multi-wavelength Fabry-Perot

August 24, 2014

Author(s)

, , , , , , , , Heeju Choi, Lori Haley

A watt balance is a promising instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key elements of such an instrument. For the new watt balance currently under construction at the National Institute of Standards and

August 24, 2014

Author(s)

, , , , ,

This paper gives a brief description of the laser interferometer system designed for the next generation watt balance experiment aimed to realize the unit of mass by direct link to Planck constant at the National Institute of Standards and Technology. The

August 24, 2014

Author(s)

, , , , , ,

The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a large complex mass measurement system with expected overall uncertainties on the order of 3 parts in 10^8.

August 24, 2014

Author(s)

, Jacques Liard, , , , , ,

A new watt balance is being constructed at NIST in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. We describe the procedures used and give results for the