The 12 th Symposium on Accelerator Physics ACCELERATOR

The 12 th Symposium on Accelerator Physics ACCELERATOR LABORATORY of TSINGHUA UNIVERSITY Intrinsic Nonlinearity of Dipole Magnets in Small Rings Haisheng Xu (许 海 生 ), Wenhui Huang, Chuanxiang Tang haishengxu@gmail. com 清华大学 程物理系 Department of Engineering Physics, Aug. 14, 2014

Outline • Introduction to TTX Tsinghua Thomson scattering X-ray source • Intrinsic nonlinearity in small rings Ø Analytical analysis; Ø Simulation; • Status of the small ring for TTX ACCELERATOR LABORATORY of TSINGHUA UNIVERSITY

TTX – Layout

TTX – Status Yingchao Du et. al. , Rev. Sci. Instrum 84, 053301 (2013)

TTX – Next A small ring!

TTX – Next

Observation of Nonlinear Resonances!

Analytical Analysis We carry out the analytical analysis in Frenet-Serret coordinate system. The Hamiltonian can be expressed as

Analytical Analysis Consider an accelerator with ideal dipoles and quadrupoles, there are transverse magnetic field only. The vector potential can be expressed as Linear Part Intrinsic Nonlinear Part Different !!!

Analytical Analysis

Analytical Analysis

Simulation – Particle Tracking By adjusting the quadrupoles’ strength simultaneously, the betatron tunes can be varied in a large range.

Varying bending radius of dipoles, we can obtain resonance strength both analytically and by particle tracking.

• Four stable islands; • Rectangular shape distortion of the phase trajectories of particles in the central region;

Baseline Design H. S. Xu, W. H. Huang, C. X. Tang, and S. Y. Lee, Phys. Rev. ST Accel. Beams, 2014, 17: 070101 [Editors’ Suggestion]

Mini-beta Design Parameters Value Betax/Betay at IP (m) 0. 194 / 0. 489 Dispersion at IP (m) 1. 00 e-3 Tune (nx / ny) 1. 40 / 1. 40 Chromaticity (xx / xy) -1. 10 / -1. 10 Horizontal damping partition number (Jx) 0. 999 Momentum compaction factor (ac) 0. 280 MINI BETA Courtesy of Tenghui Rui

Mini-beta Design nx ny 0. 03 1. 3737 1. 3711 0. 02 1. 3811 1. 3800 0. 01 1. 3898 1. 3896 0 1. 4000 -0. 01 1. 4119 1. 4117 -0. 02 1. 4253 1. 4254 -0. 03 1. 4395 1. 4425 MINI BETA Courtesy of Tenghui Rui

Summary

The 12 th Symposium on Accelerator Physics ACCELERATOR LABORATORY of TSINGHUA UNIVERSITY Thanks 谢谢