Keyword: resonance
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MOPAB014 First High Spin-Flip Efficiency for High Energy Polarized Protons polarization, dipole, proton, experiment 84
 
  • H. Huang, J. Kewisch, C. Liu, A. Marusic, W. Meng, F. Méot, P. Oddo, V. Ptitsyn, V.H. Ranjbar, T. Roser
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to minimize the systematic errors for the Relativistic Heavy Ion Collider (RHIC) spin physics experiments, flipping the spin of each bunch of protons during the stores is needed. Experiments done with single RF magnet at energies less than 2 GeV have demonstrated a spin-flip efficiency over 99%. At high energy colliders with Siberian snakes, a single magnet spin flipper does not work because of the large spin tune spread and the generation of multiple, overlapping resonances. Over past decade, RHIC spin flipper design has evolved and a sophisticated spin flipper, constructed of nine-dipole magnets, was developed to flip the spin in RHIC. A special optics choice was also used to make the spin tune spread very small. In recent experiment, 97% spin-flip efficiency was measured at both 24 and 255 GeV for the first time. The results show that efficient spin flipping can be achieved at high energies. 		 
poster icon Poster MOPAB014 [0.984 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB014  
About • paper received ※ 16 May 2021       paper accepted ※ 08 June 2021       issue date ※ 20 August 2021  
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MOPAB015 Feasibility of Polarized Deuteron Beam in the EIC polarization, solenoid, proton, detector 87
 
  • H. Huang, F. Méot, V. Ptitsyn, V.H. Ranjbar, T. Roser
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The physics program in the EIC calls for polarized neutron beam at high energies. The best neutron carriers are 3He nuclei and deuterons. Both neutron carries are expected to be used by spin physics program in the EIC. Due to the small magnetic moment anomaly of deuteron particles, much higher magnetic fields are required for spin rotation, so full Siberian snake is not feasible. However, the resonance strength is in general weak and the number of resonances is also small. It is possible to deal with individual resonances with conventional methods, such as betatron tune jump for intrinsic depolarizing resonances; and a weak partial snakes for imperfection resonances. The study shows that accelerating polarized deuteron beyond 100GeV/n is possible in the EIC. 		 
poster icon Poster MOPAB015 [0.977 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB015  
About • paper received ※ 16 May 2021       paper accepted ※ 28 May 2021       issue date ※ 13 August 2021  
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MOPAB019 Possible Application of Round-to-Flat Hadron Beam Creation Using 3rd Order Coupling Resonances for the Electron-Ion Collider emittance, sextupole, coupling, electron 99
 
  • J. Kallestrup
    PSI, Villigen PSI, Switzerland
  • X. Gu
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
An Electron-Ion Collider (EIC) is planned to be built in Brookhaven National Laboratory with the contribution from Jefferson National Laboratory. To have a high luminosity, both the EIC ion bunch and the EIC electron bunch are designed to be flat during their collision. The existing injector source provides a round beam of width 2.5 um rad transverse emittances. In this paper we investigate the option of dynamically crossing the 2Qx-Qy coupling resonance in order to create a flat-beam with emittance ratio Ex/Ey of up to 4. Furthermore, we explore the possibility of using a pulsed- or AC skew sextupole magnets to achieve a similar effect. Using one of these methods for flat beam creation will help lower the ion beam cooling time. 		 
poster icon Poster MOPAB019 [0.323 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB019  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 24 August 2021  
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MOPAB033 Monochromatization of e+e− Colliders with a Large Crossing Angle emittance, collider, luminosity, radiation 152
 
  • V.I. Telnov
    BINP SB RAS, Novosibirsk, Russia
  
  The relative center-of-mass energy spread at e+e− colliders is much larger than the widths of narrow resonances, which greatly lowers the resonance production rates of J/Psi, Psi-prime, Upsililon(nS), n=1-3. Thus, a significant reduction of the center-of-mass energy spread would open up great opportunities in the search for new physics in rare decays of narrow resonances, the search for new narrow states with small partial e+e− width. The existing monochromatization scheme is only suitable for head-on collisions, while e+e− colliders with crossing angles (the so-called Crab Waist collision scheme) can provide much higher luminosity. In this report, a new monochromatization method for colliders with a large crossing angle is discussed*. The contribution of the beam energy spread to the spread of the center-of-mass energy is canceled by introducing an appropriate energy-angle correlation at the interaction point; the relative RMS mass spread of about (3-5)10-6 seems possible. Limitations of the proposed method are also considered. This monochromatization scheme is very attractive for the Upsilon-meson region and below.
* V.I.Telnov, Monochromatization of e+e− colliders with a large crossing angle, arXiv:2008.13668 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB033  
About • paper received ※ 22 May 2021       paper accepted ※ 26 May 2021       issue date ※ 31 August 2021  
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MOPAB041 Convergence Map with Action-Angle Variables Based on Square Matrix for Nonlinear Lattice Optimization lattice, linear-dynamics, betatron, GUI 182
 
  • L.H. Yu, Y. Hidaka, F. Plassard, V.V. Smaluk
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  
  We apply square matrix method to obtain in high speed a "convergence map", which is similar but different from frequency map. The convergence map is obtained from solving nonlinear dynamical equation by iteration of perturbation method and study the convergence. The map provides information about the stability border of dynamical aperture. We compare the map with frequency map from tracking. The result indicates the new method may be applied in nonlinear lattice optimization, taking the advantage of the high speed (about 10~50 times faster) to explore x, y and the off-momentum phase space.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB041  
About • paper received ※ 09 May 2021       paper accepted ※ 26 May 2021       issue date ※ 18 August 2021  
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MOPAB049 Gyroresonant Acceleration of Electrons by an Axisymmetric Transverse Electric Field electron, acceleration, cyclotron, plasma 213
 
  • E.A. Orozco, O. Otero Olarte
    UIS, Bucaramanga, Colombia
  
  The acceleration of electrons using gyromagnetic autoresonance consist on the sustaint of the electron cyclotron resonant condition through of a magnetic field which increase on time, this scheme was propose by K. S. Golovanivsky. In this work, we considerer the gyroresonant acceleration of electrons using an axisymmetric transverse electric field and its limitations. The 2D acceleration of electrons by a TE011 cylindrical mode is studied numerically. The trajectory, energy and phase-shift between the electron transverse velocity and the electric field are determined by the numerical solution of the relativistic Newton-Lorentz equation using a finite difference scheme. The growth rate of the magnetic field obtained is such that it maintains the phase difference within the acceleration band. The study includes the evolution of the energy for electrons initially ubicated in diferents initial points. For an electron that starts from rest and located at the radial midpoint of the transverse central plane of the cavity, it is reaches an energy close to 560 keV in 625 cycles of the microwave field using an electric field amplitude of 1 kV/cm and a frequency of 2.45 GHz.  
poster icon Poster MOPAB049 [3.541 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB049  
About • paper received ※ 17 May 2021       paper accepted ※ 14 June 2021       issue date ※ 23 August 2021  
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MOPAB050 Spatial Autoresonant Acceleration of Electrons by an Axysimmetric Transverse Electric Field electron, acceleration, cyclotron, cavity 217
 
  • E.A. Orozco, O. Otero Olarte
    UIS, Bucaramanga, Colombia
  
  In this research, The autoresonance acceleration of electrons by an axisymmetric transverse electric field in presence of a stationary inhomogeneous magnetic field is studied. The dynamics of electrons is determined by the numerical solution of the relativistic Newton-Lorentz equation using a finite difference scheme. The inhomogeneous external magnetic field is generated with a three-coil system and calculated using the Biot-Savart law. The electrons move along a TE011 cylinder cavity in a stationary magnetic field whose axis coincides with the cavity axis. The magnetic field profile obtained is such that it keeps the phase difference between the electric field vector of the microwave mode and the velocity vector of the particle within the acceleration band. For an electron injected longitudinally with an energy of 1 keV and that starts at the radial midpoint of the cavity, it is accelerated up to an energy of about 185 keV using an electric field amplitude of 14 kV/cm and a frequency of 2.45 GHz at a distance of 14 cm.  
poster icon Poster MOPAB050 [3.298 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB050  
About • paper received ※ 17 May 2021       paper accepted ※ 15 June 2021       issue date ※ 30 August 2021  
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MOPAB074 Preliminary Study of Design Method for Hybrid MBA Lattice lattice, linear-dynamics, sextupole, emittance 297
 
  • J.J. Tan, Z.H. Bai, Z.L. Ren, J.H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • Q. Zhang
    INEST, Hefei, People’s Republic of China
  
  Nonlinear optimization of hybrid multi-bend-achromat (HMBA) lattice is a difficult task due to its quite limited variables of multipole magnets. As a result, it is necessary to consider nonlinear potential of the lattice in its linear design. Nonlinear dynamics can be estimated by nonlinear driving terms and detuning terms. In this paper, we propose a design method for HMBA lattice. In this method, objective functions include emittance and two indicators of nonlinear dynamics, which consist of nonlinear driving terms and detuning terms. As an example, an HMBA lattice for a 2.2 GeV storage ring with circumference of 460.8 m was designed to demonstrate the method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB074  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 21 August 2021  
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MOPAB109 A Lattice for PETRA IV Based on the Combination of Different Arc Cell Designs lattice, undulator, sextupole, emittance 399
 
  • J. Keil, I.V. Agapov, R. Brinkmann
    DESY, Hamburg, Germany
  
  The 6 GeV synchrotron light source PETRA III at DESY is in user operation since 2009. In 2016 investigations of upgrading PETRA III into a diffraction limited storage ring at 10 keV have been started. The ambitious goal is to achieve an emittance in the range of 10-30 pm*rad. For the conceptual design report (CDR) of PETRA IV a lattice based on hybrid multi-bend achromats (HMBA) has been chosen. It consists of eight arcs connected by eight long straight sections whereas each arc consists of eight HMBA cells. While this lattice variant has an advantage in terms of simplicity of magnet and girder design it is challenging in regards of multipole strengths and beam dynamic properties. However, only a part of all eight arcs will be used for undulator beamlines. This offers the possibility to choose a more relaxed optics design in the arcs without undulators while preserving the ultra-low emittance. In addition, the use of reverse bends in the undulator cells allows smaller beta functions at the undulators for an increased brilliance. The design and the beam dynamic properties of this combi lattice are discussed in this paper and compared to the lattice based on HMBA cells.  
poster icon Poster MOPAB109 [1.338 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB109  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 30 August 2021  
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MOPAB141 Terahertz Driven Compression and Time-Stamping Technique for Single-Shot Ultrafast Electron Diffraction electron, laser, FEM, radiation 492
 
  • M.A.K. Othman, A.E. Gabriel, M.C. Hoffmann, F. Ji, E.A. Nanni, X. Shen, E.J.C. Snively, X.J. Wang
    SLAC, Menlo Park, California, USA
  
  Funding: This research has been supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-76SF00515 and DE-AC02-05-CH11231.
Ultrafast structural dynamics are well understood through pump-probe characterization using ultrafast electron diffraction (UED). Advancements in electron diffraction and spectroscopy techniques open new frontiers for scientific discovery through interrogation of ultrafast phenomena, such as quantum phase transitions. Previously, we have demonstrated that strong-field THz radiation can be utilized to efficiently manipulate and compress ultrafast electron probes *, and also offer temporal diagnostics with sub-femtosecond resolution ** enabled by the inherent phase locking of THz radiation to the photoemission optical drive. In this work, we demonstrate a novel THz compression and time-stamping technique to probe solid-state materials at time scales previously inaccessible with standard UED. A high-frequency THz generation method using the organic OH-1 crystals is employed to enable a threefold reduction in the electron probes length and overall timing jitter. These time-stamped probes are used to demonstrate a substantial enhancement in the UED temporal resolution using pump-probe measurement in both photoexcited single crystal and polycrystalline samples.
* E. C. Snively et al., Phys. Rev. Lett, vol. 124, no. 6, p. 054801, 2020.
** R. K. Li et al., Phys. Rev. Accel. Beams, vol. 22, no. 1, p. 012803, Jan. 2019. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB141  
About • paper received ※ 20 May 2021       paper accepted ※ 21 June 2021       issue date ※ 19 August 2021  
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MOPAB179 Simulations of AGS Boosters Imperfection Resonances for Protons and Helions proton, simulation, experiment, quadrupole 606
 
  • K. Hock, H. Huang, F. Méot, N. Tsoupas
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
As part of the effort to increase the polarization of the proton beam for the physics experiments at RHIC, a scan of orbit harmonic corrector strengths is performed in the Booster to ensure polarization transmission through the |G gamma|=3 and 4 imperfection resonances is optimized. These harmonic scans have been simulated using quadrupole alignment data and accurately match experimental data. The method used to simulate polarized protons is extended to polarized helions for crossing the |G gamma|=5 through |G gamma|=10 imperfection resonances and used to determine the corrector strength required to cross each resonance. 		 
poster icon Poster MOPAB179 [0.437 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB179  
About • paper received ※ 17 May 2021       paper accepted ※ 31 May 2021       issue date ※ 02 September 2021  
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MOPAB187 Design and Calculation of the RF System of DC140 Cyclotron cyclotron, coupling, cavity, simulation 636
 
  • A.S. Zabanov, V.B. Zarubin
    JINR/FLNR, Moscow region, Russia
  • J. Franko, G.G. Gulbekyan, I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, V.A. Sokolov, K. Verlamov
    JINR, Dubna, Moscow Region, Russia
  
  Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The main systems of DC140 are based on the DC72 cyclotron ones that now are under reconstruction. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The designed RF-system of the DC-72 cyclotron with a half-wave cavity is not suitable due to the big vertical size. For this reason, a new quarter-wave RF-system was developed for the DC140 cyclotron project. The results of calculating the parameters of the new RF-system are given in this work.  
poster icon Poster MOPAB187 [0.488 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB187  
About • paper received ※ 17 May 2021       paper accepted ※ 24 May 2021       issue date ※ 15 August 2021  
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MOPAB211 Beam Coupling Impedances of Ferrite-Loaded Cavities: Calculations and Measurements cavity, impedance, dipole, coupling 696
 
  • S.S. Kurennoy, R.C. McCrady
    LANL, Los Alamos, New Mexico, USA
  
  We have developed an efficient method of calculating impedances in cavities with dispersive ferrite dampers. The ferrite dispersive properties in the frequency range of interest are fitted in CST, which allows using both wakefield and lossy eigenmode solvers. A simple test cavity with or without ferrite inserts is explored both numerically and experimentally. The resonance frequencies and beam coupling impedances at cavity resonances are calculated with CST to understand the mode structure. The cavity transverse coupling impedances are also measured on a test stand using a two-wire method. We compare results of impedance calculations and measurements for a few different configurations, with and without ferrites, to ensure a complete understanding of the cavity resonances and their damping with ferrite. These results are important to provide adequate damping of undesired transverse modes in induction-linac cells.  
poster icon Poster MOPAB211 [1.105 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB211  
About • paper received ※ 10 May 2021       paper accepted ※ 21 May 2021       issue date ※ 19 August 2021  
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MOPAB229 Compensations of Third-Order Resonances in J-PARC MR sextupole, operation, optics, survey 744
 
  • T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa
    KEK, Tokai, Ibaraki, Japan
  
  The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 1013 protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (νx, νy) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is νx-2νy=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3νx=64 and νx+2νy=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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MOPAB273 Nonlinear Coupling Resonances in X-Y Coupled Betatron Oscillations Near the Main Coupling Resonance in VEPP-2000 Collider betatron, coupling, collider, experiment 863
 
  • S.A. Kladov, E. Perevedentsev
    BINP SB RAS, Novosibirsk, Russia
  • S.A. Kladov, E. Perevedentsev
    NSU, Novosibirsk, Russia
  
  In the vicinity of the linear coupling resonance where the working point of the collider is positioned, we study the effect of nonlinear coupling resonances on the single-particle phase space, beam sizes and the waveform of coherent beam motion. The latter is interesting for diagnostics of the nonlinear dynamics.  
poster icon Poster MOPAB273 [1.142 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB273  
About • paper received ※ 19 May 2021       paper accepted ※ 28 May 2021       issue date ※ 21 August 2021  
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MOPAB274 Two-Stream Effects in Coherent Beam-Beam Oscillations in VEPP-2000 Collider Near the Linear Coupling Resonance betatron, coupling, collider, synchrotron 866
 
  • S.A. Kladov, E. Perevedentsev
    BINP SB RAS, Novosibirsk, Russia
  • S.A. Kladov, E. Perevedentsev
    NSU, Novosibirsk, Russia
  
  Synchro-betatron motion of colliding bunches may cause limitations of the high-luminosity performance. For a round beam collider operated near the linear coupling resonance, we present theoretical predictions of the beam-beam coherent synchro-betatron oscillation behavior under the influence of x-y coupling.  
poster icon Poster MOPAB274 [0.968 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB274  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 02 September 2021  
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MOPAB319 Development of a Fast Betatron Tune and Chromaticity Measurement System for COSY betatron, acceleration, GUI, controls 983
 
  • P.J. Niedermayer, C. Böhme, B. Breitkreutz, V. Kamerdzhiev, A. Lehrach
    FZJ, Jülich, Germany
  • A. Lehrach
    RWTH, Aachen, Germany
  
  A fast tune measurement is developed for the Cooler Synchrotron COSY at the Institut für Kernphysik of Forschungszentrum Jülich. Betatron oscillations of the beam are excited with a band-limited RF signal via a stripline kicker. Resonant transverse oscillations are then observed using capacitive beam position monitors. Based on the bunch-by-bunch beam position data the betatron tune is determined. The usage of bunch-by-bunch data is characteristic of the new system. It allows for a discrete tune measurement within a few milliseconds, as well as continuous tune monitoring during beam acceleration. The high precision tune measurement also enables determination of the beam chromaticity. Therefore, the beam momentum is varied by means of the RF frequency and the subsequent tune change is determined. For routine use during beam operation and experiments, the developed method is integrated into the control system.  
poster icon Poster MOPAB319 [1.209 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB319  
About • paper received ※ 19 May 2021       paper accepted ※ 16 June 2021       issue date ※ 12 August 2021  
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MOPAB330 Production and Performance Evaluation of a Compact Deflecting Cavity to Measure the Bunch Length in the cERL cavity, vacuum, coupling, impedance 1023
 
  • D. Naito, Y. Honda, T. Miyajima, N. Yamamoto
    KEK, Ibaraki, Japan
  
  At the KEK compact energy recovery linac, we try to generate an infrared free-electron laser (FEL). To generate the FEL, an electron bunch should be compressed along the longitudinal direction. The measurement of the bunch length is key to optimize the bunch compression. We plan to measure the bunch length by deflecting cavities in the burst mode. The deflecting cavities are required to be a time resolution of 33 fs in order to not only measure the bunch length but also resolve the structure inside the electron bunch. To achieve the requirement, we developed a c-band cavity whose RF input port is compact. The deflecting cavity is a single cell and normal conducting cavity. The deflection mode of the cavity is TM110. The 12 cavities will be located at the exit of undulators. In this presentation, we explain the design of our cavity and report the production of the first cavity. We also report the evaluation of the resonance frequency, the unloaded Q and the external Q of the cavity. From the measurements and simulations, the R/Q is estimated to be 1 mega orms. The time resolution of the cavity is expected to be 400 fs when the input RF power is 1 kW and the beam energy is 20 MeV.  
poster icon Poster MOPAB330 [12.920 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB330  
About • paper received ※ 12 May 2021       paper accepted ※ 08 June 2021       issue date ※ 28 August 2021  
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MOPAB331 Design Consideration of a Longitudinal Kicker Cavity for Compensating Transient Beam Loading Effect in Synchrotron Light Sources cavity, kicker, coupling, impedance 1027
 
  • D. Naito, S. Sakanaka, T. Takahashi, N. Yamamoto
    KEK, Ibaraki, Japan
  • T. Yamaguchi
    Sokendai, Ibaraki, Japan
  
  In ultra-low-emittance synchrotron light sources, bunch-lengthening using the combination of main and harmonic cavities is limited by the transient beam-loading (TBL) effect which is caused by gaps in the fill pattern. To manage this effect, we proposed a TBL compensation technique using a wide-band longitudinal kicker cavity*. In the future KEK-LS storage ring, for example, the kicker cavity should provide a compensation voltage of 50 kV with a -3dB bandwidth (BW) of about 5 MHz, as well as its higher-order modes (HOM) should be damped sufficiently. In this presentation, we report our conceptual design of the kicker cavity. We employed the single-mode (SM) cavity concept so that harmful HOMs are dumped by rf absorbers on the beam pipes. The distinctive feature of the SM cavity is its simple structure since it has no HOM damper on the cavity. Another feature is its low R/Q by which the TBL effect in the kicker cavity itself can be reduced significantly. We employed a frequency of 1.5 GHz (third-harmonic) and R/Q of 60 orms through optimizations. Using this kicker cavity with a double rf system, a bunch lengthening by a factor of 4.3 (i.e., 40.9 ps) is expected for the KEK-LS case.
* N.Yamamoto et al., Phys. Rrev. Acc. Beams 21, 012001 (2018) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB331  
About • paper received ※ 19 May 2021       paper accepted ※ 11 June 2021       issue date ※ 01 September 2021  
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MOPAB358 Design and Measurement of the 1.4 GHz Cavity for LEReC Linac cavity, electron, GUI, HOM 1113
 
  • B.P. Xiao, J.C. Brutus, J.M. Fite, K. Hamdi, D. Holmes, K. Mernick, K.S. Smith, J.E. Tuozzolo, T. Xin, A. Zaltsman
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Low Energy RHIC electron Cooler (LEReC) is the first electron cooler based on rf acceleration of electron bunches. To further improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, a normal conducting RF cavity at 1.4 GHz was designed and fabricated for the LINAC that will provide longer electron bunches for the LEReC. It is a single-cell cavity with an effective cavity length shorter than half of the 1.4 GHz wavelength. This cavity was fabricated and tested on-site at BNL to verify RF properties, i.e. the resonance frequency, FPC coupling strength, tuner system performance, and high power tests. In this paper, we report the RF test results for this cavity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB358  
About • paper received ※ 17 May 2021       paper accepted ※ 25 June 2021       issue date ※ 24 August 2021  
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MOPAB363 Design, Characteristics and Dynamic Properties of Mobile Plunger-based Frequency Tuning System for Coaxial Half Wave Resonators cavity, operation, experiment, controls 1129
 
  • D. Bychanok, S. Huseu, S.A. Maksimenko, A.E. Sukhotski
    INP BSU, Minsk, Belarus
  • A.V. Butenko, E. Syresin
    JINR, Dubna, Moscow Region, Russia
  • M. Gusarova, M.V. Lalayan, S.M. Polozov
    MEPhI, Moscow, Russia
  • V.S. Petrakovsky, A.I. Pokrovsky, A. Shvedov, S.V. Yurevich
    Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
  • Y. Tamashevich
    HZB, Berlin, Germany
  
  The practical realization of a prototype of the frequency tuning system (FTS) for coaxial half-wave cavities (HWR) for the Nuclotron-based Ion Collider fAcility (NICA) injector is presented. The impact of FTS on electromagnetic parameters of copper HWR prototype is experimentally studied and discussed. The most important parameters like tuning range, tuning sensitivity, the dependence of the resonant frequency on the position of the plungers are estimated. The effective operation algorithms of the proposed FTS are discussed and analyzed. The dynamic characteristics of FTS are investigated and showed the ability to adjust the frequency with an accuracy of about 70 Hz.  
poster icon Poster MOPAB363 [3.597 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB363  
About • paper received ※ 18 May 2021       paper accepted ※ 09 June 2021       issue date ※ 11 August 2021  
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TUXB04 Fabrication and Tuning of a THz-Driven Electron Gun gun, electron, cavity, GUI 1297
 
  • S.M. Lewis, A.A. Haase, J.W. Merrick, E.A. Nanni, M.A.K. Othman, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • S.M. Lewis
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported by the Department of Energy Contract No. DE-AC02-76SF00515 (SLAC) and by NSF Grant No. PHY-1734015.
We have developed a THz-driven field emission electron gun and beam characterization assembly. The two cell standing-wave gun operates in the pi mode at 110.08 GHz. It is designed to produce 360 keV electrons with 500 kW of input power supplied by a 110 GHz gyrotron. Multiple gun structures were electroformed in copper using a high precision diamond-turned mandrel. The field emission cathode is a rounded copper tip located in the first cell. The cavity resonances were mechanically tuned using azimuthal compression. This work will discuss details of the fabrication and tuning and present the results of low power measurements. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXB04  
About • paper received ※ 18 May 2021       paper accepted ※ 22 June 2021       issue date ※ 14 August 2021  
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TUPAB006 The Impact of Beam Position Monitor Tilts on Coupling Measurements coupling, optics, simulation, quadrupole 1342
 
  • L. van Riesen-Haupt, R. Tomás García
    CERN, Meyrin, Switzerland
  
  The measurement and correction of coupling resonance driving terms is a key tool for improving the performance of synchrotrons. These terms are measured by exciting the beam and observing the subsequent motion in the horizontal and vertical planes through beam position monitors. This paper outlines the impact of tilt errors in these monitors to the distortion of the amount of coupling measured between the planes and how the computation of the resonance driving terms is affected by these tilts. It also attempts to use these results for mimicking tilt errors in simulations and discusses how discrepancies in measured resonance driving terms could be used to estimate the tilt errors that cause them.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB006  
About • paper received ※ 16 May 2021       paper accepted ※ 14 June 2021       issue date ※ 12 August 2021  
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TUPAB062 Expediting APS-U Long-Term Particle Tracking with Arbitrary Order Taylor Map simulation, lattice, damping, collective-effects 1505
 
  • Y.P. Sun
    ANL, Lemont, Illinois, USA
  
  Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Truncated power series algebra was integrated within explicit symplectic integration to formulate an arbitrary order multivariate Taylor map for any given particle accelerator lattice. Tracking simulation performed with these Taylor maps shows good long term stability and physics accuracy. There is good agreement in long term particle tracking simulations between Taylor map and element by element tracking of APS-U lattice, when the particle is within 1 to 10 σ of stored beam. It is demonstrated that most of the lower order resonance driving terms, plus chromatic and geometric aberrations are reasonably preserved by the Taylor map approach. Last but maybe most important, the computation time is reduced by a factor of 20 to 50, when compared to symplectic integration based element by element tracking. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB062  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 29 August 2021  
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TUPAB195 Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning MMI, controls, optics, neutron 1865
 
  • Y.W. An, Y. Li, S.Y. Xu, Y. Yuan
    IHEP, Beijing, People’s Republic of China
  • M.T. Li
    IHEP CSNS, Guangdong Province, People’s Republic of China
  
  The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.  
poster icon Poster TUPAB195 [2.279 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195  
About • paper received ※ 13 May 2021       paper accepted ※ 17 June 2021       issue date ※ 01 September 2021  
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TUPAB213 Important Drift Space Contributions to Non-Linear Beam Dynamics sextupole, lattice, operation, storage-ring 1914
 
  • J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries
    HZB, Berlin, Germany
  
  This paper presents an in-depth analysis of the non-linear contributions of drift spaces in beam dynamics for the creation of Transverse Resonance Island Buckets (TRIBs). TRIBs have been successfully generated in BESSY II and MLS at the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB). They offer the possibility of generating a second stable orbit and, by populating the orbit with a different electron bunch pattern, allow to effectively have two distinct radiation sources in the same machine individually tailored to different user needs. We demonstrate the generation of TRIBs by order of non-linearity on simple lattice configurations by only treating the drift space as the non-linear element. Moreover, we also insert other non-linear magnets to show how they modify the already generated TRIBs from the drift spaces. We conclude by giving a qualitative analysis of the occurring effects, which provides a guideline as to when the linear approximation is insufficient and the non-linear contribution has to be taken into account.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB213  
About • paper received ※ 12 May 2021       paper accepted ※ 31 August 2021       issue date ※ 29 August 2021  
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TUPAB216 Modeling Particle Stability Plots for Accelerator Optimization Using Adaptive Sampling network, simulation, collider, dynamic-aperture 1923
 
  • M. Schenk, L. Coyle, T. Pieloni
    EPFL, Lausanne, Switzerland
  • M. Giovannozzi, A. Mereghetti
    CERN, Meyrin, Switzerland
  • E. Krymova, G. Obozinski
    SDSC, Lausanne, Switzerland
  
  Funding: This work is partially funded by the Swiss Data Science Center (SDSC), project C18-07.
One key aspect of accelerator optimization is to maximize the dynamic aperture (DA) of a ring. Given the number of adjustable parameters and the compute-intensity of DA simulations, this task can benefit significantly from efficient search algorithms of the available parameter space. We propose to gradually train and improve a surrogate model of the DA from SixTrack simulations while exploring the parameter space with adaptive sampling methods. Here we report on a first model of the particle stability plots using convolutional generative adversarial networks (GAN) trained on a subset of SixTrack numerical simulations for different ring configurations of the Large Hadron Collider at CERN. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB216  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 22 August 2021  
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TUPAB223 Design of Double- and Multi-Bend Achromat Lattices with Large Dynamic Aperture and Approximate Invariants lattice, sextupole, storage-ring, betatron 1945
 
  • Y. Li, R.S. Rainer, V.V. Smaluk
    BNL, Upton, New York, USA
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  
  Funding: Funded by U.S. Department of Energy (DOE) under Contract No. DE-SC0012704 (BNL) and DE-AC02-05CH11231 (LBNL), U.S. DOE Early Career Research Program under the Office of High Energy Physics.
A numerical method to design nonlinear double- and multi-bend achromat (DBA and MBA) lattices with approximate invariants of motion is described. The search for such nonlinear lattices is motivated by Fermilab’s Integrable Optics Test Accelerator (IOTA), whose design is based on an integrable Hamiltonian system with two invariants of motion. While it may not be possible to design an achromatic lattice for a dedicated synchrotron light source storage ring with one or more exact invariants of motion, it is possible to tune the sextupoles and octupoles in existing DBA and MBA lattices to produce approximate invariants. In our procedure, the lattice is tuned while minimizing the turn-by-turn fluctuations of the Courant-Snyder actions Jx and Jy at several distinct amplitudes, while simultaneously minimizing diffusion of the on-energy betatron tunes. The resulting lattices share some important features with integrable ones, such as a large dynamic aperture, trajectories confined to invariant tori, robustness to resonances and errors, and a large amplitude-dependent tune-spread. 		 
poster icon Poster TUPAB223 [2.392 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB223  
About • paper received ※ 10 May 2021       paper accepted ※ 15 June 2021       issue date ※ 20 August 2021  
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TUPAB224 Non-Linear Variation of the Beta-Beating Measured From Amplitude octupole, simulation, optics, target 1949
 
  • T. Pugnat, B. Dalena
    CEA-IRFU, Gif-sur-Yvette, France
  • A. Franchi
    ESRF, Grenoble, France
  • R. Tomás García
    CERN, Geneva, Switzerland
  
  Accelerator physics needs advanced modeling and simulation techniques, for beam stability studies but also for the measurement of beam parameters like the Twiss parameters. A deeper understanding of magnetic field non-linearities effects will greatly help in the improvement of future circular collider design, performance, and diagnostics. This paper studies the variation of the \beta-beating with the action of the particle generated by non-linear Resonance Driving Terms, both from a theoretical and an experimental point of view.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB224  
About • paper received ※ 18 May 2021       paper accepted ※ 06 July 2021       issue date ※ 21 August 2021  
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TUPAB227 Simultaneous Compensation of Phase and Amplitude Dependent Geometrical Resonances Using Octupoles octupole, sextupole, lattice, emittance 1960
 
  • F. Plassard, Y. Hidaka, Y. Li, T.V. Shaftan, V.V. Smaluk, G.M. Wang
    BNL, Upton, New York, USA
  
  As the new generation of light sources are pushing toward diffraction limited storage rings with ultra-low emittance beams, nonlinear beam dynamics become increasingly difficult to control. It is a common practice for modern designs to use a sextupole scheme that allows simultaneous correction of natural chromaticity and energy independent, or geometrical, sextupolar resonances. However, the remaining higher order terms arising from the cross talks of the sextupole families set a strong limitation on the achievable dynamic aperture. This paper presents a simulation-based recipe to use octupoles together with this sextupole scheme to provide simultaneous self-compensation of linear amplitude dependent tune shift together with phase-dependent octupolar and higher order geometrical resonant driving terms. The correction method was built based on observations made on a simple FODO model, then applied to a realistic low emittance lattice, designed in the framework of the upgrade of the National Synchrotron Light Source II (NSLS-II).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB227  
About • paper received ※ 19 May 2021       paper accepted ※ 23 June 2021       issue date ※ 14 August 2021  
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TUPAB231 Cooling of an Annular Beam by Using Nonlinear Effects dipole, emittance, extraction, proton 1968
 
  • F. Capoani, M. Giovannozzi, R. Tomás García
    CERN, Geneva, Switzerland
  • A. Bazzani, F. Capoani
    Bologna University, Bologna, Italy
  
  In recent years, nonlinear effects have been used to modify the transverse beam distribution by crossing nonlinear resonances adiabatically. This allows generating transversally split beams, in which the initial single Gaussian is divided into several ones depending on the order and stability type of the resonance used. Nonlinear effects could be used to try and cool a beam by acting on its transverse beam distribution. In this paper, we present and discuss the special case of a beam with an annular distribution, showing how the resulting emittance could be reduced by means of nonlinear effects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB231  
About • paper received ※ 10 May 2021       paper accepted ※ 16 June 2021       issue date ※ 21 August 2021  
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TUPAB232 Linear Coupling and Adiabaticity of Emittance Exchange coupling, emittance, extraction, proton 1972
 
  • F. Capoani, M. Giovannozzi
    CERN, Geneva, Switzerland
  • A. Bazzani, F. Capoani
    Bologna University, Bologna, Italy
  • A.I. Neishtadt
    IKI, Moscow, Russia
  • A.I. Neishtadt
    Loughborough University, Leicestershre, United Kingdom
  
  In circular accelerators, crossing the coupling resonance induces the exchange of the transverse emittances, provided the process is adiabatic. In this paper, we introduce a theoretical framework to analyze the resonance-crossing process, based on Hamiltonian mechanics, which is capable of explaining all the features of the emittance exchange process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB232  
About • paper received ※ 11 May 2021       paper accepted ※ 16 June 2021       issue date ※ 27 August 2021  
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TUPAB245 WAKEFIELD AND HEAT LOAD STUDY OF THE GATE VALVES AT ILSF STORAGE RING impedance, storage-ring, wakefield, simulation 2018
 
  • N. Khosravi, E. Ahmadi, M. Akhyani
    ILSF, Tehran, Iran
  • M. Akhyani
    EPFL, Lausanne, Switzerland
  • S. Dastan
    IPM, Tehran, Iran
  • A. Khosravi
    LAPRI, Tehran, Iran
  
  As one part of the ILSF storage ring, the rf-shield of the gate valves generates considerable interest in terms of wake impedance and heat-load. Inside the gate valves, there is a vacuity, which causes low frequencies resonances, and it can lead to beam instabilities. Therefore, controlling and eliminating these frequencies will be substantial. A radio frequency rf-shield structure, which conceals this transverse gap of the gate valves, is indispensable for low emittance chambers. This paper analyzes the wake impedance and thermal behavior of a finger-band RF shield in the gate valve.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB245  
About • paper received ※ 16 May 2021       paper accepted ※ 14 June 2021       issue date ※ 13 August 2021  
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TUPAB251 Impedance Studies of a Corrugated Pipe for KARA impedance, simulation, radiation, electron 2039
 
  • S. Maier, M. Brosi, A. Mochihashi, A.-S. Müller, M.J. Nasse, M. Schwarz
    KIT, Karlsruhe, Germany
  
  Funding: DFG project 431704792 in the ANR-DFG collaboration project ULTRASYNC and the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology".
At the KIT storage ring KARA (KArlsruhe Research Accelerator) it is planned to install an impedance manipulation structure in a versatile chamber to study and eventually control the influence of an additional impedance on the beam dynamics and the emitted coherent synchrotron radiation. For this purpose the impedance of a corrugated pipe is under investigation. In this contribution, we present first results of simulations showing the impact of different structure parameters on its impedance and wake potential. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB251  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 26 August 2021  
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TUPAB252 Minimization of NICA Collider Impedance impedance, collider, simulation, space-charge 2043
 
  • S.A. Melnikov, I.N. Meshkov
    JINR, Dubna, Moscow Region, Russia
  • K.G. Osipov
    JINR/VBLHEP, Dubna, Moscow region, Russia
  
  The paper presents the results of the longitudinal impedance minimization for the beam tube section in the arches of the NICA collider ring, consisting of a pumping pipe, a BPM station, and a bellows assembly, and considers the contribution of the impedance of this section to the ion beam stability in the NICA collider ring. To confirm the efficiency of the optimized design, a BPM prototype was fabricated, and a test bench was built for further laboratory measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB252  
About • paper received ※ 13 May 2021       paper accepted ※ 14 June 2021       issue date ※ 10 August 2021  
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TUPAB269 Transverse Impedance of Lossy Circular Metal-Dielectric Waveguides impedance, GUI, radiation, wakefield 2093
 
  • M. Ivanyan, L.V. Aslyan
    CANDLE SRI, Yerevan, Armenia
  • K. Flöttmann, F. Lemery
    DESY, Hamburg, Germany
  
  The properties of the transverse impedance of a dielectric-loaded metallic circular waveguide are investigated taking into account losses in the outer metallic pipe and in the inner dielectric layer. The dispersion relations, impedances, and wake functions for dipole modes are analyzed and compared for thin and thick dielectric layer cases. The correspondence of the resonant frequencies of the longitudinal monopole and transverse dipole impedances is established.  
poster icon Poster TUPAB269 [0.906 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB269  
About • paper received ※ 16 May 2021       paper accepted ※ 28 May 2021       issue date ※ 10 August 2021  
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TUPAB272 Observation of Long-Range Wakefield Effects Generated in an Off-Resonance Tesla-Type Cavity cavity, HOM, electron, wakefield 2101
 
  • A.H. Lumpkin, D.R. Edstrom, A. Lunin, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The interest in controlling emittance dilution effects due to off-axis beam transport in accelerator cavities and the resulting dipolar modes is especially important for the facilities with lower emittance beams. The Fermilab Accelerator Science and Technology (FAST) facility has a unique configuration of two single cavities after the photocathode rf gun followed by a cryomodule. The second capture cavity (CC2) was run 15 kHz off resonance and without rf power while a 25-MeV beam was injected into it. The beam centroid effects were tracked by 10 rf button BPMs with bunch-by-bunch position readout capability downstream in a 12-m drift. Possible LRW effects seemed to dominate our previously observed near-resonant HOM effects at mode 14 in this cavity. This mode also shifted in frequency compared to that of the tuned case based on direct measurements. Submacropulse vertical position slewing of 1400 microns at 11 m downstream was observed with a 125 pC/bunch, 50 bunches per macropulse, and 25-MeV beam. The y-position slew amplitudes as a function of z were also measured. Horizontal positions also showed a slew effect. Both are emittance-dilution effects which one wants to mitigate. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB272  
About • paper received ※ 18 May 2021       paper accepted ※ 09 June 2021       issue date ※ 20 August 2021  
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WEXA04 The RCS Design Status for the Electron Ion Collider electron, injection, lattice, emittance 2521
 
  • V.H. Ranjbar, M. Blaskiewicz, Z.A. Conway, D.M. Gassner, C. Hetzel, B. Lepore, H. Lovelace III, I. Marneris, F. Méot, C. Montag, J. Skaritka, N. Tsoupas, E. Wang, F.J. Willeke
    BNL, Upton, New York, USA
  • J.M. Grames, J. Guo, F. Lin, V.S. Morozov, T. Satogata
    JLab, Newport News, Virginia, USA
  • D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The design of the Electron-Ion Collider Rapid Cycling Synchrotron (RCS) to be constructed at Brookhaven National Laboratory is advancing to meet the injection requirements for the Electron Storage Ring (ESR). Over the past year activities are focused on developing the approach to inject two 28 nC bunches every second, up from the original design of one 10nC bunch every second. The solution requires several key changes concerning the injection and extraction kickers, charge accumulation via bunch merging and a carefully calibrated RF acceleration profile to match the longitudinal emittance required by the ESR. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA04  
About • paper received ※ 19 May 2021       paper accepted ※ 31 August 2021       issue date ※ 10 August 2021  
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WEPAB008 Numerical Noise Study in EIC Beam-Beam Simulations simulation, electron, proton, emittance 2592
 
  • D. Xu, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Luo, C. Montag
    BNL, Upton, New York, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  In the Electron-Ion Collider (EIC) design, a flat beam collision scheme is adopted to achieve 1e34 luminosity. We found that the vertical growth of the proton beam is much larger than of the round beam. In this article we present the numerical noise study about the number of macroparticles, the electron slice number, and the electron bunch length. Both weak-strong and strong-strong simulation methods are used. It turns out the proton emittance growth in the strong-strong simulation mainly comes from the numberical noise. This study helps us to perform beam-beam simulation correctly for EIC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB008  
About • paper received ※ 17 May 2021       paper accepted ※ 31 August 2021       issue date ※ 31 August 2021  
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WEPAB009 Study of Harmonic Crab Cavity in EIC Beam-Beam Simulations cavity, simulation, betatron, electron 2595
 
  • D. Xu, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Luo, C. Montag
    BNL, Upton, New York, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  In the Electron-Ion Collider (EIC) design, crab cavities are adopted to compensate the geometric luminosity loss from the crossing angle. From previous studies, higher-order synchro-betatron resonances are excited since the hadron beam is long and the crossing angle is large. To reduce the luminosity degradation rate, different combinations of harmonic crab cavities are studied with both weak-strong and strong-strong simulation methods. The frequency map analysis (FMA) is also used for comparison. This study helps determine the crab cavity parameters for the future EIC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB009  
About • paper received ※ 17 May 2021       paper accepted ※ 23 June 2021       issue date ※ 28 August 2021  
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WEPAB010 Full Range Tune Scan Studies Using Graphics Processing Units with CUDA in EIC Beam-Beam Simulations simulation, betatron, GPU, cavity 2598
 
  • D. Xu, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Luo, C. Montag
    BNL, Upton, New York, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  The hadron beam in the Electron-Ion Collider (EIC) suffers high order betatron and synchro-betatron resonances. In this paper, we present a weak-strong full range (0.0~0.5) fractional tune scan with a step size as small as 0.001. Multiple Graphics Processing Units (GPUs) are used to speed up the simulation. A code parallelized with MPI and CUDA is implemented. The good tune region from weak-strong scan is further checked by the self-consistent strong-strong simulation. This study provides beam dynamics guidance in choosing proper working points for the future EIC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB010  
About • paper received ※ 17 May 2021       paper accepted ※ 23 June 2021       issue date ※ 12 August 2021  
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WEPAB150 Monotron Beam Break Up Instability Analysis HOM, cavity, klystron, dipole 2968
 
  • V. Volkov, V.M. Petrov
    BINP SB RAS, Novosibirsk, Russia
  
  New features of monotron beam break up (BBU) instability such as the typing of high order monopole modes (HOMs)in each cavity by two classes one of them are stable and other ones are unstable, HOM effective quality factor depending on average beam current, and normalized invariable threshold current individually characterizes each HOM are investigated in this article in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB150  
About • paper received ※ 19 May 2021       paper accepted ※ 09 June 2021       issue date ※ 31 August 2021  
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WEPAB188 New Method to Search for Axion-Like Particles Demonstrated with Polarized Beam at the COSY Storage Ring polarization, storage-ring, experiment, dipole 3057
 
  • S. Karanth
    Jagiellonian University, Kraków, Poland
  
  The axion was originally proposed to explain the small size of CP violation in quantum chromodynamics. It might be a candidate for dark matter in the universe. Axions or axion-like particles (ALPs) when coupled to gluons induce an oscillating Electric Dipole Moment (EDM) along the nucleon’s spin direction. At the Cooler Synchrotron (COSY) in Jülich, this principle was used to perform a first test experiment to search for ALPs using an in-plane polarized deuteron beam. If the spin precession frequency equals the EDM oscillation frequency, a resonance occurs that accumulates the rotation of the polarization out of the ring plane. Since the axion frequency is unknown, the beam momentum was ramped to search for a vertical polarization jump that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the EDM oscillations. We scanned a frequency window of about a 1-kHz width around the spin precession frequency of 121 kHz. This talk will describe the experiment and show preliminary results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB188  
About • paper received ※ 19 May 2021       paper accepted ※ 01 July 2021       issue date ※ 31 August 2021  
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WEPAB222 Impedance Evaluation of Masks in the HEPS Storage Ring impedance, wakefield, radiation, synchrotron 3145
 
  • N. Wang, S.K. Tian, J.Q. Wang
    IHEP, Beijing, People’s Republic of China
  • J.Q. Wang
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
  
  Masks are commonly used in photon light sources to protect sensitive elements from synchrotron radiations. In the ultra-low emittance rings, small aperture vacuum chambers are adopted in order to reach the very high gradient in the quadrupoles, while many masks are required due to the high radiation power density. Therefore, the impedance of the masks becomes one of the dominant contributors to the impedance budget. In this paper, the impedance is evaluated among different mask designs. Meanwhile, the impedance cross-talk between adjacent masks is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB222  
About • paper received ※ 18 May 2021       paper accepted ※ 06 July 2021       issue date ※ 15 August 2021  
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WEPAB250 Interplay Between Space Charge, Intra-Beam Scattering, and Synchrotron Radiation Effects emittance, space-charge, damping, synchrotron 3220
 
  • M. Zampetakis, F. Antoniou, H. Bartosik, Y. Papaphilippou
    CERN, Geneva, Switzerland
  • M. Zampetakis
    University of Crete, Heraklion, Crete, Greece
  
  The objective of this research is to study the interplay of synchrotron radiation, intra-beam scattering, and space charge in the vicinity of excited resonances. In this respect, two modules were developed to simulate intra-beam scattering and synchrotron radiation effects and plugged into pyORBIT to be used together with its space charge module. Different regimes of synchrotron motion were used to study the response of the beam to a lattice resonance when space charge, intra-beam scattering and synchrotron radiation are present.  
poster icon Poster WEPAB250 [0.536 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB250  
About • paper received ※ 17 May 2021       paper accepted ※ 21 July 2021       issue date ※ 25 August 2021  
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WEPAB279 On Wire-Corrector Optimization in the HL-LHC and the Appearance of Special Aspect Ratios target, optics, coupling, insertion 3297
 
  • D. Kaltchev
    TRIUMF, Vancouver, Canada
  
  For the two high-luminosity insertions of the Large Hadron Collider (HL-LHC) current bearing wire correctors are intended to mitigate the detrimental effect of long-range beam-beam interactions. With respect to finding the optimum longitudinal location of the wire, two special locations corresponding to the special values 2 and 1/2 of the beta-function aspect ratio have been previously shown to provide simultaneous cancellation of multiple two-dimensional Resonance Driving Terms. This paper attempts to explain the appearance of such special aspect ratios.  
poster icon Poster WEPAB279 [1.238 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB279  
About • paper received ※ 14 May 2021       paper accepted ※ 19 July 2021       issue date ※ 13 August 2021  
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WEPAB280 Two-Dimensional Beam-Beam Invariant with Applications to HL-LHC optics, closed-orbit, lattice, luminosity 3301
 
  • D. Kaltchev
    TRIUMF, Vancouver, Canada
  
  Long-range beam-beam interactions represent the most severe limitation on the performance and achievable luminosity of circular collider. The paper presents a two-dimensional nonlinear Courant Snyder Invariant derived to first order in the beam-beam perturbation and based on the two-dimensional coefficients in the Fourier expansion of the Beam-beam Hamiltonian. Its validity in case of HL-LHC lattices with realistic beam-beam setup is verified with MadX tracking.  
poster icon Poster WEPAB280 [1.235 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB280  
About • paper received ※ 14 May 2021       paper accepted ※ 06 July 2021       issue date ※ 12 August 2021  
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WEPAB295 Parameter Estimation of Short Pulse Normal-Conducting Standing Wave Cavities cavity, gun, coupling, RF-structure 3351
 
  • S. Pfeiffer, J. Branlard, F. Burkart, M. Hoffmann, H. Schlarb
    DESY, Hamburg, Germany
  
  The linear accelerator ARES (Accelerator Research Experiment at SINBAD) is a new research facility at DESY. Electron bunches with a maximum repetition rate of 50 Hz are accelerated to a target energy of 155 MeV. The facility aims for ultra-stable sub-femtosecond arrival-times and high peak-currents at the experiment, placing high demands on the reference distribution and field regulation of the RF structure. In this contribution, we present the physical parameter estimation of key RF properties such as cavity detuning not directly measurable on the RF field decay. The method can be used as a fast monitor of inner cell temperature. The estimated properties are finally compared with the measured ones.  
poster icon Poster WEPAB295 [0.860 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB295  
About • paper received ※ 19 May 2021       paper accepted ※ 05 July 2021       issue date ※ 26 August 2021  
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WEPAB363 Dynamic Response of Spallation Volume to Beam Raster on the European Spallation Source Target target, operation, simulation, proton 3552
 
  • Y. Lee
    ESS, Lund, Sweden
  
  To achieve a desirably low beam intensity on the target, the European Spallation Source (ESS) adopted a beam raster system at the high beta beam transport part of the linac. The raster system paints the beam on the target with frequencies up to 40 kHz within the 2.86 ms beam pulse, to form a uniformly expanded beam footprint. While the beam raster reduces the time-averaged beam current density to a level that the 5 years of design lifetime of the target system can be achieved with a high operational reliability, it could potentially induce deleterious dynamic excitations in the spallation volume made of tungsten. The stress wavelets created by raster sweeps can be amplified if the sweep frequency is in tune with a resonance mode of the tungsten volume. This coherent interference of the wavelets could lead to a high dynamic stress in tungsten, posing a risk of premature failure of the target. In this paper, the dynamic response of the spallation volume of the ESS target to different beam raster frequencies has been analysed, using multi-physics simulations based on measured material data. Finally, a safe operational range of the beam raster frequency band is proposed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB363  
About • paper received ※ 12 May 2021       paper accepted ※ 02 July 2021       issue date ※ 01 September 2021  
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WEPAB400 Forced Coupling Resonance Driving Terms coupling, dipole, optics, simulation 3646
 
  • A. Wegscheider, R. Tomás García
    CERN, Meyrin, Switzerland
  
  At the LHC, coupling is routinely measured using forced oscillations of the beam through excitation with an AC-dipole. The driving of the particle motion has an impact on the measurement of resonance driving terms. Recent findings suggest that the current models describing the forced motion are neglecting a local effect of the AC-dipole, creating a jump of the amplitude of the resonance driving terms. This work presents a study of the improvement of coupling measurements for typical LHC optics as well as its upgrade project HL-LHC, by using the new model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB400  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 20 August 2021  
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THPAB016 Revisit of Nonlinear Dynamics in Hénon Map Using Square Matrix Method lattice, sextupole, site, dynamic-aperture 3788
 
  • Y. Hao, K.J. Anderson
    FRIB, East Lansing, Michigan, USA
  • L.H. Yu
    BNL, Upton, New York, USA
  
  Funding: Work supported by the Accelerator Stewardship program, award number DE-SC0019403 with the U.S. Department of Energy
Hénon map (2D or 4D) represents a thin lens sextupole in an otherwise linear lattice and had been well studied for many decades. We revisit the nonlinear properties of the Hénon map with the aid of the square matrix method and Arnold theorem, including acquiring the resonance structure and amplitude-dependent frequency. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB016  
About • paper received ※ 17 May 2021       paper accepted ※ 12 July 2021       issue date ※ 17 August 2021  
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THPAB067 Simulation of the APS-U Orbit Motion Due to RF Noise simulation, synchrotron, cavity, photon 3911
 
  • V. Sajaev
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
APS Upgrade storage ring will keep the same rf system that is presently used at APS. This rf system has amplitude and phase noise dominated by the lines at 60, 180, and 360 Hz. APS presently operates with synchrotron frequency close to 2 kHz, which is far away from the rf noise frequencies, and still the rf system noise contributes over 2 micrometers rms into the horizontal orbit noise due to beam energy variation. APS-U will operate with a bunch-lengthening cavity, which will lower the synchrotron frequency down to about 200 Hz. This could potentially lead to large orbit noise and other negative consequences due to energy variation caused by the rf system noise. In this paper, we will present simulations of the rf noise-induced orbit motion at APS and APS-U and define the rf amplitude and phase noise requirements that need to be achieved for APS-U operation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB067  
About • paper received ※ 12 May 2021       paper accepted ※ 13 July 2021       issue date ※ 23 August 2021  
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THPAB075 Collective (In)stability Near the Coupling Resonance wakefield, coupling, simulation, impedance 3933
 
  • R.R. Lindberg
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
We show how to treat transverse collective instabilities when operating in the vicinity of the coupling (or tune difference) resonance. We begin by defining the approximate independent degrees of freedom including both linear coupling and chromatic effects. We then show how the destabilizing force due to wakefields and the stabilizing chromatic effects can be described by a linear combination of the horizontal and vertical motion that depends upon how close one is to the resonance. The theory agrees well with tracking studies, and will be relevant for those next-generation storage rings that plan to operate near the coupling resonance to produce nearly round beams, including the multi-bend achromat upgrade for the Advanced Photon Source. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB075  
About • paper received ※ 20 May 2021       paper accepted ※ 27 July 2021       issue date ※ 01 September 2021  
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THPAB169 A Mechanism for Emittance Growth Based on Non-Linear Islands in LHC octupole, emittance, ECR, operation 4082
 
  • E.H. Maclean, M. Giovannozzi, T.H.B. Persson, R. Tomás García
    CERN, Geneva, Switzerland
  
  Landau octupoles are used in the LHC to prevent coherent instabilities of the circulating beam. The reduction of their strength occurring during the energy ramp can transport particles in nonlinear islands to larger amplitude. This has the potential to lead to emittance growth and to beam-losses. Beam-based studies and simulations of emittance growth during Landau octupole ramps performed in the LHC are presented to explore this mechanism in more detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB169  
About • paper received ※ 18 May 2021       paper accepted ※ 14 July 2021       issue date ※ 14 August 2021  
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THPAB174 T-BMT Spin Resonance Tracker Code for He3 with Six Snakes polarization, emittance, HOM, betatron 4101
 
  • V.H. Ranjbar, H. Huang, Y. Luo, F. Méot, V. Ptitsyn
    BNL, Upton, New York, USA
  • G.H. Hoffstaetter, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • F. Lin, V.S. Morozov
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy .
Polarization lifetime for He3 using two and six snakes are studied using the T-BMT Spin Resonance Tracker code. This code integrates a reduced spinor form of the T-BMT equation including only several spin resonances and the kinematics of synchrotron motion. It was previously benchmarked against RHIC polarization lifetime under the two snake system *.
* Phys. Rev.Accel. Beams 22 (2019) 9, 091001 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB174  
About • paper received ※ 20 May 2021       paper accepted ※ 02 July 2021       issue date ※ 28 August 2021  
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THPAB183 New Longitudinal Beam Production Methods in the CERN Proton Synchrotron Booster space-charge, emittance, proton, cavity 4130
 
  • S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, E. Renner
    CERN, Meyrin, Switzerland
  • E. Renner
    TU Vienna, Wien, Austria
  
  As part of the LHC Injectors Upgrade (LIU) project, significant improvements were made to the CERN Proton Synchrotron Booster (PSB) during the 2019/2020 long shutdown, including a new Finemet-based wideband RF system, renovated longitudinal beam control, and a new magnetic cycle. To meet the requirements of the diverse experimental program, the PSB provides beams with intensities spanning three orders of magnitude and a large range of longitudinal emittances. To maximize the brightness, in particular for the LHC beams, the voltages at low energy are designed to reduce the impact of transverse space charge using a second RF harmonic in bunch lengthening mode. At high energies, the risk of longitudinal microwave instability is avoided by optimizing the longitudinal distribution to raise the instability threshold. RF phase noise is applied to provide controlled longitudinal emittance blow-up and to shape the longitudinal distribution. This paper discusses the design of the RF functions used to meet the beam specifications, whilst ensuring longitudinal stability.  
poster icon Poster THPAB183 [6.692 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB183  
About • paper received ※ 18 May 2021       paper accepted ※ 22 July 2021       issue date ※ 20 August 2021  
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THPAB243 Optimizing Mu2e Spill Regulation System Algorithms extraction, controls, simulation, network 4281
 
  • A. Narayanan
    Northern Illinois University, DeKalb, Illinois, USA
  • K.J. Hazelwood, M.A. Ibrahim, V.P. Nagaslaev, D.J. Nicklaus, P.S. Prieto, B.A. Schupbach, K. Seiya, R.M. Thurman-Keup, N.V. Tran
    Fermilab, Batavia, Illinois, USA
  • H. Liu, S. Memik, R. Shi, M. Thieme
    Northwestern University, Evanston, Illinois, USA
  
  Funding: The work has been performed at Fermilab. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359.
A slow extraction system is being developed for the Fermilab’s Delivery Ring to deliver protons to the Mu2e experiment. During the extraction, the beam on target experiences small intensity variations owing to many factors. Various adaptive learning algorithms will be employed for beam regulation to achieve the required spill quality. We discuss here preliminary results of the slow and fast regulation algorithms validation through the computer simulations before their implementation in the FPGA. Particle tracking with sextupole resonance was used to determine the fine shape of the spill profile. Fast semi-analytical simulation schemes and Machine Learning models were used to optimize the fast regulation loop. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB243  
About • paper received ※ 20 May 2021       paper accepted ※ 28 July 2021       issue date ※ 20 August 2021  
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THPAB337 Resonance Control System for the PIP-II IT HWR Cryomodule cavity, controls, feedback, cryomodule 4446
 
  • P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus, S. Sankar Raman
    Fermilab, Batavia, Illinois, USA
  • L.R. Doolittle, S. Paiagua, C. Serrano
    LBNL, Berkeley, California, USA
  
  The HWR (half-wave-resonator) cryomodule is the first one in the superconducting section of the PIP-II LINAC project at Fermilab. PIP-II IT is a test facility for the project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The HWR cryomodule comprises 8 cavities operating at a frequency of 162.5 MHz and accelerating beam up to 10 MeV. Resonance control of the cavities is performed with a pneumatically operated slow tuner which compresses the cavity at the beam ports. Helium gas pressure in a bellows mounted to an end wall of the cavity is controlled by two solenoid valves, one on the pressure side and one on the vacuum side. The resonant frequency of the cavity can be controlled in one of two modes. A pressure feedback control loop can hold the cavity tuner pressure at a fixed value for the desired resonant frequency. Alternately, the feedback loop can regulate the cavity tuner pressure to bring the RF detuning error to zero. The resonance controller is integrated into the LLRF control system for the cryomodule. The control system design and performance of the resonance control system are described in this paper.  
poster icon Poster THPAB337 [4.426 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB337  
About • paper received ※ 12 May 2021       paper accepted ※ 26 July 2021       issue date ※ 27 August 2021  
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THPAB338 Performance of the LLRF System for the Fermilab PIP-II Injector Test cavity, controls, LLRF, cryomodule 4450
 
  • P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus
    Fermilab, Batavia, Illinois, USA
  • L.R. Doolittle, C. Serrano
    LBNL, Berkeley, California, USA
  
  PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The 8-cavity half-wave-resonator (HWR) cryomodule operating at 162.5 MHz is followed by the 8-cavity single-spoke resonator(SSR1) cryomodule operating at 325 MHz. The LLRF systems for both cryomodules are based on a common SOC FPGA-based hardware platform. The resonance control systems for the two cryomodules are quite different, the first being a pneumatic system based on helium pressure and the latter a piezo/stepper motor type control. The data acquisition and control system can support both CW and Pulsed mode operations. Beam loading compensation is available which can be used for both manual/automatic control in the LLRF system. The user interfaces include EPICS, Labview, and ACNET. Testing of the RF system has progressed to the point of being ready for a 2 mA beam to be accelerated to 25 MeV. The design and performance of the field control and resonance control system operation with beam are presented in this paper.  
poster icon Poster THPAB338 [5.482 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB338  
About • paper received ※ 13 May 2021       paper accepted ※ 27 July 2021       issue date ※ 24 August 2021  
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