Keyword: dynamic-aperture
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MOPOST009 EIC Crab Cavity Multipole Analysis and Their Effects on Dynamic Aperture cavity, multipole, luminosity, collider 66
 
  • Q. Wu, B.P. Xiao
    BNL, Upton, New York, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • Y. Luo
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Crab cavity is essential for retrieving the loss in luminosity due to the large crossing angle in the two colliding beam lines of the Electron Ion Collider (EIC). Due to the asymmetric design of the proton beam crab cavity, the fundamental mode consists of contributions from higher order multipoles. These multipole modes may change during fabrication and installation of the cavities, and therefore affect the local dynamic aperture. Thresholds for each order of the multipoles are applied to ensure dynamic aperture requirements at these crab cavities. In this paper, we analyzed the strength of the multipoles due to fabrication and installation accuracies, and set limitations to each procedure to maintain the dynamic aperture requirement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST009  
About • Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 10 July 2022
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MOPOST042 Using Dynamic Indicators for Probing Single-Particle Stability in Circular Accelerators lattice, alignment, software, simulation 168
 
  • C.E. Montanari, A. Bazzani, G. Turchetti
    Bologna University, Bologna, Italy
  • M. Giovannozzi, C.E. Montanari
    CERN, Meyrin, Switzerland
 
  Computing the long-term behaviour of single-particle motion is a numerically intensive process, as it requires a large number of initial conditions to be tracked for a large number of turns to probe their stability. A possibility to reduce the computational resources required is to provide indicators that can efficiently detect chaotic motion, which are considered precursors to unbounded motion. These indicators could allow skilful selection of a set of initial conditions that could then be considered for long-term tracking. The chaotic nature of each orbit can be assessed by using fast-converging dynamic indicators, such as the Fast Lyapunov Indicator (FLI), the Reversibility Error Method (REM), and the Smallest and Global Alignment Index (SALI and GALI). These indicators are widely used in the field of Celestial Mechanics, but not so widespread in Accelerator Physics. They have been applied both to a modulated Hénon map, as a toy model, as well as to realistic lattices of the High-Luminosity LHC. In this paper, we discuss the results of detailed numerical studies, focusing on their performance in detecting chaotic motions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST042  
About • Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022  
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MOPOST047 Determination of the Phase-Space Stability Border with Machine Learning Techniques luminosity, hadron, storage-ring, simulation 183
 
  • F.F. Van der Veken, R. Akbari, M.P. Bogaert, E. Fol, M. Giovannozzi, A.L. Lowyck, C.E. Montanari, W. Van Goethem
    CERN, Meyrin, Switzerland
 
  The dynamic aperture (DA) of a hadron accelerator is represented by the volume in phase space that exhibits bounded motion, where we disregard any disconnected parts that could be due to stable islands. To estimate DA in numerical simulations, it is customary to sample a set of initial conditions using a polar grid in the transverse planes, featuring a limited number of angles and using evenly distributed radial amplitudes. This method becomes very CPU intensive when detailed scans in 4D, and even more in higher dimensions, are used to compute the dynamic aperture. In this paper, a new method is presented, in which the border of the phase-space stable region is identified using a machine learning (ML) model. This allows one to optimise the computational time by taking the complex geometry of the phase space into account, using adaptive sampling to increase the density of initial conditions along the border of stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST047  
About • Received ※ 06 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022  
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MOPOST048 Efficient Representation of Realistic 3D Static Magnetic Fields for Symplectic Tracking and First Applications for Frequency Analysis and Dynamic Aperture Studies in ELENA resonance, electron, lattice, emittance 187
 
  • L. Bojtár
    CERN, Meyrin, Switzerland
 
  The algorithm called SIMPA has a new and unique approach to long-term 4D tracking of charged particles in arbitrary static electromagnetic fields. Field values given on the boundary of the region of interest are reproduced by an arrangement of hypothetical magnetic or electric point sources surrounding the boundary surface. The vector and scalar potentials are obtained by summing the contributions of each source. The second step of the method improves the evaluation speed of the potentials and their derivatives by orders of magnitude. This comprises covering the region of interest by overlapping spheres, then calculating the spherical harmonic expansion of the potentials on each sphere. During tracking, field values are evaluated by calculating the solid harmonics and their derivatives inside a sphere containing the particle. Frequency analysis and dynamic aperture studies in ELENA is presented. The effect of the end fields and the perturbation introduced by the magnetic system of the electron cooler on dynamic aperture is shown. The dynamic aperture calculated is the direct consequence of the geometry of the magnetic elements, no multipole errors have been added to the model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST048  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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MOPOST055 The EIC Rapid Cycling Synchrotron Dynamic Aperture Optimization electron, sextupole, lattice, resonance 210
 
  • H. Lovelace III, C. Montag, V.H. Ranjbar
    BNL, Upton, New York, USA
  • F. Lin
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  With the design of the Electron-Ion Collider (EIC), a new Rapid Cycling Synchrotron (RCS) must be designed to accelerate the electron bunches from 400 MeV up to 18 GeV. An optimized dynamic aperture with preservation of polarization through the energy ramp was found. The codes DEPOL, MAD-X, and BMAD are used in modeling the dynamics and spin preservation. The results will be discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST055  
About • Received ※ 27 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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MOPOTK007 Reverse Bend Option for a 6 GeV Storage Ring Lattice emittance, lattice, injection, SRF 441
 
  • L. Hoummi, N. Carmignani, L.R. Carver, F. Cianciosi, S.M. Liuzzo, T.P. Perron, S.M. White
    ESRF, Grenoble, France
 
  Several high-energy synchrotron facilities adopted the Hybrid Multi-Bend Achromat scheme (HMBA) developed at and for the ESRF-EBS [LATTICE]. The considered lattice has been developed for a generic 6 GeV storage ring (SR) of 1100m circumference. It includes a short bending (SB) magnet at the center of the cell, and achieves a  ∼ §I{70}{πco\metre\radian} equilibrium horizontal emittance. The optics of such SR are modified introducing reverse bending magnets to further reduce the natural horizontal emittance to §I{53}{πco\metre\radian}. The impact of such modification on dynamic aperture and lifetime is assessed and optimized.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK007  
About • Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
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MOPOTK056 Data-Driven Chaos Indicator for Nonlinear Dynamics and Applications on Storage Ring Lattice Design resonance, storage-ring, lattice, linear-dynamics 596
 
  • Y. Li, R.S. Rainer
    BNL, Upton, New York, USA
  • Y. Jiao, J. Wan
    IHEP, People’s Republic of China
  • A. Liu
    Purdue University, West Lafayette, Indiana, USA
 
  Funding: This research mainly 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.
A data-driven chaos indicator concept is introduced to characterize the degree of chaos for nonlinear dynamical systems. The indicator is represented by the prediction accuracy of surrogate models established purely from data. It provides a metric for the predictability of nonlinear motions in a given system. When using the indicator to implement a tune-scan for a quadratic Henon map, the main resonances and their asymmetric stop-band widths can be identified. When applied to particle transportation in a storage ring, as particle motion becomes more chaotic, its surrogate model prediction accuracy decreases correspondingly. Therefore, the prediction accuracy, acting as a chaos indicator, can be used directly as the objective for nonlinear beam dynamics optimization. This method provides a different perspective on nonlinear beam dynamics and an efficient method for nonlinear lattice optimization. Applications in dynamic aperture optimization are demonstrated as real world examples.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK056  
About • Received ※ 16 May 2022 — Accepted ※ 12 June 2022 — Issue date ※ 03 July 2022  
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WEPOPT004 Acceleration and Crossing of Transition Energy Investigation Using an RF Structure of the Barrier Bucket Type in the NICA Accelerator Complex collider, focusing, acceleration, proton 1829
 
  • S.D. Kolokolchikov, A.A. Melnikov, Y. Senichev
    RAS/INR, Moscow, Russia
  • E. Syresin
    JINR, Dubna, Moscow Region, Russia
 
  The dynamic of longitudinal motion in Barrier Bucket RF structure is considered. To preserve the stability of the proton beam during the acceleration to the experiment energy it is necessary to cross the transition energy and a rapid jump of transition energy is possible. The influence of the second-order slip factor is taking into account, as well as the space charge effect. The dynamic aperture is investigated for various gradients of focusing quadrupoles and corresponding working points which is necessary for transition crossing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT004  
About • Received ※ 16 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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WEPOPT037 Dynamic Aperture Evaluation for EIC Hadron Storage Ring with Crab Cavities and IR Nonlinear Magnetic Field Errors electron, proton, cavity, simulation 1927
 
  • Y. Luo, J.S. Berg, W. Fischer, X. Gu, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, H. Witte, D. Xu
    BNL, Upton, New York, USA
  • Y. Hao
    FRIB, East Lansing, Michigan, USA
  • V.S. Morozov
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  • T. Satogata
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177.
The electron ion collider (EIC) presently under construction at Brookhaven National Laboratory will collider polarized high energy electron beams with hadron beams with luminosities up to 1034 cm-2s-1 in the center mass energy range of 20-140 GeV. In this article, we evaluate the dynamic aperture of the Hadron Storage Ring (HSR) with symplectic element-by-element tracking. Crab cavities, nonlinear magnetic field errors, and weak-strong beam-beam interaction are included. We compared the dynamic aperture from head-on collision to crossing-angle collision and found the reason for the dynamic aperture drop. We also studied the field error tolerances for IR magnets and for some particular magnets.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT037  
About • Received ※ 22 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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WEPOPT059 Corrections of Systematic Normal Decapole Field Errors in the HL-LHC Separation/Recombination Dipoles target, resonance, simulation, dipole 1991
 
  • J. Dilly, M. Giovannozzi, R. Tomás García, F.F. Van der Veken
    CERN, Meyrin, Switzerland
 
  Funding: This work has been supported by the HiLumi Project and been sponsored by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Re-search.
Magnetic measurements revealed that the normal decapole (b5) errors of the recombination dipoles (D2) could have a systematic component of up to 11 units. Based on previous studies, it was predicted that the current corrections would not be able to compensate this, thereby leading to a degradation of the dynamic aperture by about 0.5 - 1 ’. On the other hand, the separation dipole D1 is expected to have a systematic b5 component of 6-7 units and its contribution to the resonance driving terms will partly compensate the effect of D2, due to the opposite field strength of the main component. Simulations were performed with the HL-LHC V1.4 lattice to test these concerns and to verify the compensation assumption. In addition, various normal decapole resonance driving terms were examined for correction, the results of which are presented in this contribution.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT059  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022
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WEPOTK061 Lattice Design of the UVSORIV Storage Ring emittance, lattice, storage-ring, electron 2205
 
  • E. Salehi, M. Fujimoto, M. Katoh, Y. Taira
    UVSOR, Okazaki, Japan
  • L. Guo
    Nagoya University, Nagoya, Japan
  • M. Katoh
    HSRC, Higashi-Hiroshima, Japan
 
  We are designing a storage ring lattice for the future plan of UVSOR. As a candidate, we have designed a storage ring of 1 GeV electron energy, which is higher than the present value, 750 MeV. The magnetic lattice is based on a compact double bend achromat cell, which consists of two bending magnets and four focusing magnets, all of which are of combined function. The circumference is around 82.5 m. The emittance is around 4 nm in the achromatic condition, which becomes lower in the non-achromatic condition. The lattice of 6-fold symmetry has six straight sections of 4 m long and six of 1.5 m long. Undulators can radiate nearly diffraction-limited light in VUV. If we install high field multipole wiggler at the short straight sections, they can provide high flux tender X-rays. We are expecting the usage of a laser-based accelerator as the injector, which might be developed in the next decade. As an alternative plan, we have designed a traditional injector, which consists of a linear accelerator and a booster synchrotron and can be constructed inside of the storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK061  
About • Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 30 June 2022
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THPOST005 Tracking Dynamic Aperture in the iRCMS Hadrontherapy Synchrotron dipole, synchrotron, acceleration, focusing 2442
 
  • F. Méot, P.N. Joshi, N. Tsoupas
    BNL, Upton, New York, USA
  • J.P. Lidestri, M.R. Subramanian
    Best Medical International, Springfield, USA
 
  Funding: Work supported by a TSA between Best Medical International and Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Dynamic aperture (DA) studies which are part of the ion Rapid Cycling Medical Synchrotron (iRCMS) lattice design have been undertaken. They are aimed at supporting on-going plans to launch the production of the six magnetic sectors which comprise the iRCMS racetrack arcs. The main bend magnetic gap is tight, so allowing smaller volume magnets and resulting in a compact ring. The DA happens to be commensurate with the mechanical aperture, thus tracking accuracy is in order. In that aim, DA tracking uses the OPERA field maps of the six 60 degree magnetic sectors of the arcs. Simulation outcomes are summarized here.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST005  
About • Received ※ 03 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 02 July 2022
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