Paper 
Title 
Page 
WEA2C1 
Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS 
228 

 S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang
IHEP, Beijing, People’s Republic of China



The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by halfinteger resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.



Slides WEA2C1 [4.710 MB]


DOI • 
reference for this paper
※ doi:10.18429/JACoWHB2023WEA2C1


About • 
Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023 
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WEA2C2 
Measurement of Transverse Statistical Dependence for NonGaussian Beam Distributions via Resonances in the CERN PSB 
231 

 E.R. Lamb, F. Asvesta, H. Bartosik, G. Sterbini
CERN, Meyrin, Switzerland
 E.R. Lamb
EPFL, Lausanne, Switzerland



This work addresses the origins and the effects of the statistical dependence in nonGaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that nonGaussian heavytailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the xy plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to nonGaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.



Slides WEA2C2 [1.249 MB]


DOI • 
reference for this paper
※ doi:10.18429/JACoWHB2023WEA2C2


About • 
Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023 
Cite • 
reference for this paper using
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※ LaTeX,
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