Keyword: resonance
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MOPA25 Simulated Lorentz Force Detuning Compensation with a Double Lever Tuner on a Dressed ILC/1.3 GHz Cavity at Room Temperature cavity, controls, flattop, SRF 106
 
  • C. Contreras-Martinez, Y.M. Pischalnikov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Pulsed SRF linacs with high accelerating gradients experience large frequency shifts caused by Lorentz force detuning (LFD). A piezoelectric actuator with a resonance control algorithm can maintain the cavity frequency at the nominal level thus reducing the RF power. This study uses a double lever tuner with a piezoelectric actuator for compensation and another piezoelectric actuator to simulate the effects of the Lorentz force pulse. A double lever tuner has an advantage by increasing the stiffness of the cavity-tuner system thus reducing the effects of LFD. The tests are conducted at room temperature and with a dressed 1.3 GHz 9-cell cavity.  
poster icon Poster MOPA25 [0.931 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA25  
About • Received ※ 03 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 11 August 2022 — Issue date ※ 13 August 2022
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MOPA81 Study of Nonlinear Dynamics in the 4-D Hénon Map Using the Square Matrix Method and Iterative Methods dynamic-aperture, linear-dynamics, lattice, sextupole 232
 
  • K.J. Anderson, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • L.H. Yu
    BNL, Upton, New York, USA
 
  Funding: Accelerator Stewardship program under award number DE-SC0019403 US Department of Energy, Office of Science, High Energy Physics under award number DE-SC0018362 and Michigan State University
The Hénon Map represents a linear lattice with a single sextupole kick. This map has been extensively studied due to its chaotic behavior. The case for the two dimensional phase space has recently been revisited using ideas from KAM theory to create an iterative process that transforms nonlinear perturbed trajectories into rigid rotations*. The convergence of this method relates to the resonance structure and can be used as an indicator of the dynamic aperture. The studies of this method have been extended to the four dimensional phase space case which introduces coupling between the transverse coordinates.
*Hao, Y., Anderson, K., & Yu, L. H. (2021, August). Revisit of Nonlinear Dynamics in Hénon Map Using Square Matrix Method. https://doi.org/10.18429/JACoW-IPAC2021-THPAB016
 
poster icon Poster MOPA81 [3.103 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA81  
About • Received ※ 19 July 2022 — Revised ※ 04 August 2022 — Accepted ※ 15 August 2022 — Issue date ※ 26 August 2022
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MOPA82 Space Charge Driven Third Order Resonance at AGS Injection experiment, emittance, space-charge, injection 236
 
  • M.A. Balcewicz, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • Y. Hao, H. Huang, C. Liu, K. Zeno
    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
Resonance line crossings at significant space charge tune shifts can exhibit various phenomena due to periodic resonance crossing from synchrotron motion* and manifests as halo generation and bunch shortening along with the more mundane emittance growth and beam loss. An injection experiment is conducted at the AGS using the fast wall current monitor and electron collecting Ionization Profile Monitor (eIPM) to probe third order resonances to better characterize the resonance crossing over a 4 ms time scale. This experiment shows some agreement with previous experiments, save for lack of bunch shortening, possibly due to relative resonance strength.
* G. Franchetti et al. PRSTAB 13, 114203. 2010
 
poster icon Poster MOPA82 [1.924 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA82  
About • Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 19 August 2022 — Issue date ※ 24 August 2022
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TUPA56 Beam Coupling Impedances of Asymmetric Components of the Scorpius Induction Linac impedance, linac, dipole, vacuum 469
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
 
  The transverse beam coupling impedance of induction linacs must be minimized to avoid beam breakdown instability. The vacuum chamber of the Scorpius linac contains complicated asymmetric elements. We present calculations of the transverse impedance for three asymmetric discontinuities: (1) a pumping section between accelerating cells, which contains vacuum plenum, pumping grid, and bellows; (2) a fast flapper valve; and (3) a debris blocker at the end of the linac. The dipole transverse impedance is calculated with CST Studio using both wakefield solver and eigen solver.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA56  
About • Received ※ 01 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 08 August 2022 — Issue date ※ 06 October 2022
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TUPA64 Analysis of Resonant Converter Topology for High-Voltage Modulators high-voltage, operation, impedance, klystron 486
 
  • M. Sanchez Barrueta, J.T.M. Lyles, M.D.M. Morris
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work Supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
At the Los Alamos Neutron Science Center (LANSCE), we are considering various topologies to replace obsolete charging supplies and capacitor banks that provide high-voltage direct-current (DC) power to the 44, 805-MHz klystron modulators that drive the LANSCE Coupled Cavity Linac (CCL). Among the possible replacement topologies is the High Voltage Converter Modulator (HVCM), originally designed at LANSCE for use at the Spallation Neutron Source (SNS), to be used as a pulsed high-voltage power supply for klystron-based RF transmitters. The HVCM topology uses high frequency transformers with resonant LC networks for efficient energy conversion and a frequency dependent gain, which permits the use of frequency modulation as a control variable to afford pulse flattening and excellent regulation as demonstrated at SNS. A mathematical analysis is presented that links the converter resonant tank components to the frequency dependent output behavior of the converter modulator.
LA-UR-22-25179
 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA64  
About • Received ※ 03 August 2022 — Revised ※ 10 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 22 August 2022
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WEYE3 Improvements to the Recycler/Main Injector to Deliver 850 kW+ proton, booster, operation, experiment 578
 
  • R. Ainsworth, P. Adamson, D. Capista, N. Chelidze, K.J. Hazelwood, I. Kourbanis, O. Mohsen, D.K. Morris, M.J. Murphy, M. Wren, M. Xiao
    Fermilab, Batavia, Illinois, USA
  • C.E. Gonzalez-Ortiz
    MSU, East Lansing, Michigan, USA
 
  The Main Injector is used to deliver a 120 GeV high power proton beam for Neutrino experiments. The design power of 700 kW was reached in early 2017 but further improvements have seen a new sustained peak power of 893 kW. Two of the main improvements include the shortening of the Main Injector ramp length as well optimizing the slip-stacking procedure performed in the Recycler to reduce the amount of uncaptured beam making its way into the Main Injector. These improvements will be discussed in this paper as well future upgrades to reach higher beam powers.  
slides icon Slides WEYE3 [24.715 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEYE3  
About • Received ※ 02 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 18 August 2022
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WEPA49 Ferrite-Free Circulator for Precise Measurements of SRF Cavities with High Q-Factor ISOL, cavity, SRF, experiment 742
 
  • A.I. Pronikov, A.Yu. Smirnov
    RadiaBeam, Santa Monica, California, USA
  • A.A. Krasnok
    Florida International University, Miami, Florida, USA
  • S.N. Romanenko
    Zaporizhzhya National Technical University, Zaporizhzhya, Ukraine
  • V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work was supported by the US Department of Energy, Offices of High Energy and Nuclear Physics, awards DE-SC0020926 and DE-SC0022439.
In this work, we suggest and investigate new magnetless circulators based on three resonators connected in a loop and parametrically modulated in time with mutual phase lag. The first design consists of three Fano resonators with a spectrally asymmetric response, in contrast to schemes based on the Lorentz resonators explored thus far. The second design includes three Fano-Lorentz resonators, i.e., it also possesses spatial asymmetry. We demonstrate that the asymmetric approach provides strong and reversible isolation for the practically feasible modulation amplitude and rate. The results of our work are promising for precise measurements of superconducting radio frequency cavities with high Q-factor.
 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA49  
About • Received ※ 04 August 2022 — Revised ※ 07 August 2022 — Accepted ※ 09 August 2022 — Issue date ※ 13 September 2022
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WEPA74 Characterization of Fully Coupled Linear Optics with Turn-by-Turn Data optics, lattice, coupling, quadrupole 805
 
  • Y. Li, R.S. Rainer, V.V. Smaluk
    BNL, Upton, New York, USA
 
  Funding: This research used resources of the NSLS-II, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.
In the future diffraction-limited light source rings, fully coupled linear optics to generate round beams is preferable. While machine tune approaching to linear difference resonances, small random errors, such as quadrupole rolls, can result in fully coupled optics. Consequently, some uncertainty exists in such optics due to random errors distributions. Given beam position monitors turn-by-turn readings, the harmonic analysis method was used to characterize the coupled Ripken Twiss parameters.
 
poster icon Poster WEPA74 [0.889 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA74  
About • Received ※ 25 July 2022 — Revised ※ 30 July 2022 — Accepted ※ 08 August 2022 — Issue date ※ 19 August 2022
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WEPA80 Progress on Convergence Map Based on Square Matrix for Nonlinear Lattice Optimization lattice, dynamic-aperture, storage-ring, linear-dynamics 823
 
  • L.H. Yu, Y. Hao, Y. Hidaka, F. Plassard, V.V. Smaluk
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
 
  Funding: DOE.
We report progress on applying the square matrix method to obtain in high speed a "convergence map", which is similar but different from a frequency map. We give an example of applying the method to optimize a nonlinear lattice for the NSLS-II upgrade. The convergence map is obtained by solving the nonlinear dynamical equation by iteration of the perturbation method and studying the convergence. The map provides information about the stability border of the dynamical aperture. We compare the map with the frequency map from tracking. The result in our example of nonlinear optimization of the NSLS-II lattice shows the new method may be applied in nonlinear lattice optimization, taking advantage of the high speed (about 30~300 times faster) to explore x, y, and the off-momentum phase space.
 
poster icon Poster WEPA80 [5.392 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA80  
About • Received ※ 19 July 2022 — Revised ※ 26 July 2022 — Accepted ※ 08 August 2022 — Issue date ※ 10 August 2022
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