Iron lamination and interlaminar insulation for high-frequency pulsed magnets.

N. Nishimori,S. Takano,T. Iwashita,T. Taniuchi,H. Nakanishi,Y. Takemura,H. Yamaguchi,T. Inagaki,T. Watanabe,H. Tanaka,K. Fukami

doi:10.1063/5.0074226

Abstract

In high-frequency pulsed magnets, such as kickers in particle accelerators, it is essential to reduce eddy currents that could be induced in the magnet core during excitation not to distort and attenuate the magnetic field pulse. A novel iron lamination scheme with additional interlaminar insulation is proposed for the magnet core of such pulsed magnets. A laminated steel sheet core is formed by alternately stacking thin steel and insulation sheets. For application to matched kicker magnets for accelerators, test magnets with the new and conventional iron lamination were designed, assembled, and extensively evaluated. The pulsed magnetic field waveforms of two test magnets with the new lamination successfully matched to below 0.1% over the entire pulse duration, which was significantly better than those with the conventional lamination. Among the applications of the developed high-frequency pulsed magnets, beam injection kickers for the coming next generation light sources and future colliders, where suppression of the transient stored-beam oscillation during beam injection is crucial, are considered to be promising.

Highlights

High-frequency pulsed magnets are widely used in particle accelerators as kickers and septa that control the particle beam in ejection, switching the beam delivery route, and injection
In high-frequency pulsed magnets, such as kickers in particle accelerators, it is essential to reduce eddy currents that could be induced in the magnet core during excitation not to distort and attenuate the magnetic field pulse
The high saturation flux density in the laminated steel sheet core is suitable to high-field compact magnets, including kickers and septa that are extensively demanded for generation light sources and future high energy colliders

Summary

INTRODUCTION

High-frequency pulsed magnets are widely used in particle accelerators as kickers and septa that control the particle beam in ejection, switching the beam delivery route, and injection. Matched kicker magnets are necessary to minimize the transient horizontal oscillation of the stored beam at beam injection Factors such as the uneven metallic coating on the inner surface of the ceramic chambers at the pulsed magnets and the leakage field from the septa can affect the amplitude of the. SPring-8-II aims at providing highly brilliant and coherent x-ray photon beams with a renewed lowemittance storage ring In this new storage ring, one pair of two matched kicker magnets with the same kick angle that are separated by the phase advance of π radians is going to be employed to form a closed injection orbit bump in the beam injection section to minimize the transient horizontal oscillation of the stored beam at the beam injection..

Design concept

Magnet parameters

Effective B–H curve of the core material

Mismatch of the pulsed current waveform

Mismatch of the pulsed field waveform

DISCUSSION

Findings

Prospects for next generation light sources

CONCLUSIONS