TY  - CONF
AU  - Huang, R.
AU  - Chen, L.J.
AU  - Jia, Q.K.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - Study on a Polarization Controllable Undulator for High-Gain Free Electron Lasers
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - SASE FEL can generate intense and coherent linearly-polarized X-ray when high energy electron beams travelling through a long planar undulator. It is also of great importance and interest to control the polarization of FEL. One possible solution is utilizing a customized undulator to adjust the magnetic field direction. By tuning the displacement of the magnetic block arrangement, variation of polarization could be achieved. In this paper we study on a polarization controllable undulator to realize the variable polarized magnetic field. Different shapes and design considerations of the magnetic block configuration will be introduced. The value of peak field and the region of good field will be analysed and discussed.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 18
EP  - 20
KW  - polarization
KW  - undulator
KW  - controls
KW  - HOM
KW  - radiation
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-MOPB003
UR  - https://jacow.org/sap2023/papers/mopb003.pdf
ER  - 

TY  - CONF
AU  - He, T.L.
AU  - Bai, Z.H.
AU  - Li, W.W.
AU  - Xu, H.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - In diffraction-limited storage rings, non-evaporable getter (NEG) coatings are generally used to assure the ultrahigh vacuum, which, however, also increase the beam coupling impedance that can affect beam dynamics. Ignoring the influence of coating roughness, the impact of NEG coatings on the impedance mainly depends on the coating thickness and resistivity. In this paper, we investigate the impedance characteristics of a round CuCrZr vacuum chamber coated by NEG with different thickness and resistivity.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 30
EP  - 33
KW  - impedance
KW  - vacuum
KW  - ECR
KW  - storage-ring
KW  - coupling
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-MOPB010
UR  - https://jacow.org/sap2023/papers/mopb010.pdf
ER  - 

TY  - CONF
AU  - Wei, B.F.
AU  - Bai, Z.H.
AU  - Feng, G.Y.
AU  - Tan, J.J.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - Analysis of the Fluctuation of Resonance Driving Terms for Nonlinear Lattice Optimization
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - Minimizing resonance driving terms (RDTs) of nonlinear magnets is a traditional approach to enlarge the dynamic aperture (DA) of a storage ring. The local cancellation of nonlinear dynamics, which is adopted by some diffraction-limited storage rings, is more effective than the global cancellation. The former has smaller fluctuation of RDTs along the ring. In this paper, the correlation between two kinds of RDT fluctuations is found. The qualitative analysis shows that minimizing the RDT fluctuations is beneficial for controlling the crossing terms and thus enlarging the DA. This qualitative analysis is supported by the statistical analysis of nonlinear solutions of a double-bend achromat lattice.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 41
EP  - 44
KW  - sextupole
KW  - storage-ring
KW  - resonance
KW  - lattice
KW  - controls
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-MOPB017
UR  - https://jacow.org/sap2023/papers/mopb017.pdf
ER  - 

TY  - CONF
AU  - Zhang, L.H.
AU  - Li, S.Y.
AU  - Liu, T.
AU  - Luo, Q.
AU  - Tang, J.Y.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - Longitudinal Beam Dynamics Design for Super Tau-Charm Facility
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - The project of Super Tau-Charm Facility (STCF) pro-posed in China, as a new-generation high-luminosity e⁺/e⁻ collider in the low-energy region with the center-of-mass energy of 2¿7 GeV, is well underway. The luminosity is targeted at 1.0×10³⁵ cm⁻²s⁻¹ at the optimized beam energy of 2 GeV. Longitudinal beam dynamics becomes of great importance for the STCF due to the constraints from the novel beam-beam effect called coherent X-Z instability and severe beam collective effects. In this paper, we will develop an iterative optimization model for the STCF longitudinal beam dynamics design, which takes into account the influence of transverse dynamics, coherent X-Z instability, and collective effects.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 45
EP  - 48
KW  - luminosity
KW  - impedance
KW  - collective-effects
KW  - damping
KW  - synchrotron
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-MOPB018
UR  - https://jacow.org/sap2023/papers/mopb018.pdf
ER  -