Construction, Measurement, Shimming, and Performance of the NIST-4 Magnet System

Published

June 6, 2014

Author(s)

Frank Seifert, Alireza Panna, Leon Chao, Bing Han, Shisong Li, Yusi A. Cao, Darine El Haddad, Stephan Schlamminger, Heeju Choi, Lori Haley

Abstract

The magnet system is one of the key elements of a watt balance. For the new watt balance currently under construction at the National Institute of Standards and Technology a permanent magnet system was chosen. We describe the detailed construction of the magnet system, first measurements of the field profile, and shimming techniques that were used to achieve a flat field profile. We further characterize the most important aspects of the magnet and give order of magnitude estimates for several systematic effects that originate from the magnet system.

Citation

IEEE Transactions on Instrumentation and Measurement

Pub Type

Journals

Download Paper

https://doi.org/10.1109/TIM.2014.2323138

Local Download

Keywords

mass, permanent magnet, Planck constant, watt balance, SI units

Citation

Seifert, F. , Panna, A. , Chao, L. , Han, B. , Li, S. , Cao, Y. , El Haddad, D. , Schlamminger, S. , Choi, H. and Haley, L. (2014), Construction, Measurement, Shimming, and Performance of the NIST-4 Magnet System, IEEE Transactions on Instrumentation and Measurement, [online], https://doi.org/10.1109/TIM.2014.2323138, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915033 (Accessed October 8, 2025)