Measurement of magnetic permeability of steel laminations of Booster gradient magnets

TL;DR

This paper presents measurements of the frequency-dependent magnetic permeability of steel laminations used in Booster gradient magnets, crucial for understanding their influence on beam dynamics at Fermilab.

Contribution

It introduces a novel method to estimate magnetic permeability across a wide frequency range using S-parameter analysis of microstrip lines made from laminated steel.

Findings

Permeability varies with frequency up to 1 GHz

Provides data for improved magnet modeling

Enhances understanding of steel's magnetic properties in accelerator magnets

Abstract

New experiments at Fermilab require higher beam intensities at Booster, resulting in higher influence of magnet steel on the beam. In order to carefully take these effects into account it is necessary to know geometric and material properties of magnets. This work is dedicated to the measurement of magnetic permeability of steel laminations of Booster gradient magnets as a complex function of frequency in the frequency range from several megahertz up to 1 GHz. The magnetic permeability is estimated by analyzing S-parameters of microstrip lines made up from laminated steel.