|Title||Magnet System for the Quantum Electromechanical Metrology Suite|
|Publication Type||Journal Article|
|Year of Publication||2020|
|Authors||R. R. Marangoni, D. Haddad, F. Seifert, L. S. Chao, D. B. Newell, and S. Schlamminger|
|Journal||IEEE Trans. Instrum. Meas.|
|Type of Article||Article|
|Keywords||Air gaps, Force, Kibble balance, magnet circuit, magnet system, Magnetic circuits, Magnetic noise, Magnetic shielding, mass measurement, Permanent magnets, Superconducting magnets|
The design of the permanent magnet system for the new quantum electromechanical metrology suite (QEMMS) is described. The QEMMS, developed at the National Institute of Standards and Technology (NIST), consists of a Kibble balance, a programmable Josephson voltage standard, and a quantum Hall resistance standard. It will be used to measure masses up to 100 g with relative uncertainties below 2 x 10(-8). The magnet system is based on the design of the NIST-4 magnet system with significant changes to adopt to a smaller Kibble balance and to overcome known practical limitations. Analytical models are provided to describe the coil-current effect and model the forces required to split the magnet into two parts to install the coil. Both models are compared to simulation results obtained with finite-element analysis and measurement results. Other aspects such as the coil design and flatness of Bl profile are considered.