Conceptual design of the spin rotator for the SuperKEKB High Energy Ring
Date
2022-01-04
Authors
Peng, Yuhao
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Abstract
This project focuses on the conceptual design of the spin rotator for a proposed
electron polarization upgrade of the SuperKEKB. The goal is to achieve the longitudinal
electron polarization at the interaction point (IP). In this design, four existing
dipoles will be replaced with four rotator magnets on both sides of the IP. The rotator
magnet structure consists of dipole-solenoid combined function magnets with
skew-quadrupoles installed on top to decouple the x-y plane. The advantage of this
design is that the original machine geometry is maintained, and the original machine
can be recovered by turning off the solenoid-quadrupole in the rotator magnet. With
Bmad, a powerful lattice simulation tool applied to perform the optimizations for this
design, the longitudinal spin alignment at the IP reaches a significantly high level,
greater than 99.99%. Furthermore, the influence of the installation of the spin rotator
on the original machine dynamics is minimized to an acceptable level.
Description
Keywords
Electron Polarization, Spin Rotator, SuperKEKB, L-Rot, R-Rot