Paper  Title  Page 

TUPMK016  Using Time Evolution of the Bunch Structure to Extract the Muon Momentum Distribution in the Fermilab Muon g2 Experiment  1526 


Beam dynamics plays an important role in achieving the unprecedented precision on measurement of the muon anomalous magnetic moment in the Fermilab Muon g2 Experiment. It needs to find the muon momentum distribution in the storage ring in order to evaluate the electric field correction to muon anomalous precession frequency. We will show how to use time evolution of the beam bunch structure to extract the muon momentum distribution by applying a fast rotation analysis on the decay electron signals.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018TUPMK016  
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WEYGBE3 
New Features of Beamstruhlung Important for CrabWaist e^{+}e^{−} Colliders  


It is already known that beamstrahlung put a limitation on attainable luminosity of circular high energy e^{+}e^{−} colliders (like FCCee and CEPC), it determines beam lifetimes, increase the energy spread and leads to a beam lengthening. Current projects take these effects into account using well known synchrotron radiation (SR) formulas. In this talk I show that these formulas are not applicable for colliders with crabwaist collisions (all new projects of circular e^{+}e^{−} colliders) because at these colliders the deflection angle during the beam collisions θ< 1/γ. In this case the characteristic maximum frequency is ω_{m} ≈cγ^{2}/σ instead of the SR critical frequency ω_{c}≈cγ^{3}/ρ (where σ is the crossing length), the ratio ω_{m}/ω_{c} >1 and the spectrum is completely different. As result all effects due to beamstrahlung are stronger than give standard SR formulas. In the talk results of exact numerical calculation of beamstrahlung spectra for parameter region of e^{+}e^{−} circular collides are presented with analysis and conclusion.  
Slides WEYGBE3 [2.282 MB]  
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THPAF005  Simulations of Modulator for Coherent Electron Cooling  2953 


Highly resolved numerical simulations have been performed using the code SPACE for the modulator, the first section of the Coherent electron cooling (CeC) device installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Simulation results have been benchmarked with analytical solution using uniform electron beam with realistic thermal velocities. Electron bunches with Gaussian distribution and quadrupole field with realistic settings have been applied in the simulations to predict the modulation process and final bunching factors induced by ions with reference and offreference energies in the CeC experiment at BNL RHIC.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAF005  
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THPAF006  Simulations of Cooling Rate and Diffusion for Coherent Electron Cooling Experiment  2957 


Starttoend numerical simulations have been performed using the code SPACE and GENESIS for the single pass of gold ions through the coherent electron cooling (CeC) device installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Cooling rate of CeC experiment has been predicted using offreference energy ions in a finite Gaussian electron beam through a realistic beamline, in which settings of quadrupoles and freeelectron laser (FEL) device are relevant to BNL RHIC.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAF006  
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THPAF074  Landau Damping Studies for the FCC: Octupole Magnets, Electron Lens and BeamBeam Effects  3150 


Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI. Stability studies for the FCChh operational cycle are explored using Landau octupoles and electron lenses alone and in the presence of longrange as well as headon beambeam effects. Pros and cons of the various methods are compared and an optimum operational scenario to guarantee the maximum stability is proposed. 

DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAF074  
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THPAK108  Fourier Coefficients of LongRange BeamBeam Hamiltonian via TwoDimensional Bessel functions  3486 


The twodimensional coefficients (resonance basis) in the Fourier expansion of the longrange beambeam Hamiltonian have been expressed through the (less familiar) generalized modified Bessel functions of two arguments. We describe an efficient method to compute these coefficients based on the above representation. The method has been applied to HLLHC lattices and benchmarked against MadX simulations of detuning.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAK108  
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THPAK131  Investigation of TwoBunch Train Compression by Velocity Bunching  3548 


Two electron beamlets, also referred as twobunch train with adjustable time and energy spacing are popular in many applications such as two color FEL and pumpprobe experiments. We investigate compression of twobunch train via velocity bunching scheme in a traveling wave accelerator (TWA) tube by varying the phase of TWA tube in a very large range. Beam dynamics simulations show that when the phase injected into the accelerator tube for the beam is set to ≪100 degree, velocity bunching occurs in a deep overcompression mode, where twobunch train is continuously tunable in time and in energy space, and the emittance of each subbunch is also preserved. In the experiment, we use energy spectrum and defecting cavity to diagnose the train's energy space and time space respectively, the measurements demonstrated that twobunch train through deep overcompression scheme is separated both in time and in energy space, which also agree well with the predictions.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAK131  
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THPAL157  Investigation of Transverse Wakefield and Beam Break Up Effect in Irradiation Linacs  4020 


Study of beam break up effect in linacs has been done in recent years. The beaminduced high order dipolar modes, especially the TM11like mode were investigated for the linacs both in travelling wave and backward travelling wave. Measurements of beambreak up in a travelling wave linac were carried out and results are discussed. Moreover, a theoretical model was developed for the irradiation linacs to study the detailed interaction between the transverse wakefield and the electron beam.  
DOI •  reference for this paper ※ https://doi.org/10.18429/JACoWIPAC2018THPAL157  
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