Keyword: lattice
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MOXA01 Commissioning and Restart of ESRF-EBS SRF, injection, storage-ring, MMI 1
 
  • S.M. White, N. Carmignani, L.R. Carver, J. Chavanne, L. Farvacque, L. Hardy, J. Jacob, G. Le Bec, S.M. Liuzzo, T.P. Perron, Q. Qin, P. Raimondi, J.-L. Revol, K.B. Scheidt
    ESRF, Grenoble, France
  
  The ESRF operates a 6 GeV 4th generation light source, the ESRF-EBS. This storage ring is the first to implement the Hybrid Multi-Bend Achromat lattice (HMBA). The HMBA lattice provides a reduction of the horizontal emittance of approximately a factor 30 with respect to the former Double Bend Achromat (DBA) structure, considerably improving the brilliance and transverse coherence of the ESRF accelerator complex while maintaining large horizontal acceptance and excellent lifetime performance. In this report, the characteristics of the HMBA lattice will be reviewed and the beam commissioning results and first operation experience of the new ESRF storage ring will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA01  
About • paper received ※ 11 May 2021       paper accepted ※ 31 August 2021       issue date ※ 01 September 2021  
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MOXA02 Status of the APS-U Project emittance, injection, storage-ring, photon 7
 
  • R.O. Hettel
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Sci- ence, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357.
The Advanced Photon Source Upgrade (APS-U) project at the Argonne National Laboratory will re-place the existing 7-GeV, 1.1-km circumference dou-ble bend storage ring lattice with a new 6-GeV hybrid 7BA lattice that will reduce horizontal electron emit-tance from 3 nm-rad to 42 pm-rad, including IBS ef-fects for 200-mA operation. With new optimized per-manent magnet and superconducting undulators, an increase in spectral brightness of two to three orders of magnitude in the 10-100 keV X-ray energy range will be realized. The project includes nine new high performance beamlines and fifteen enhanced beam-lines that will exploit the high brightness and coher-ence of the new facility. The project is in full swing, more than 50% complete by cost, and is on schedule for first beam sometime in mid-2024, a slip of 10 months from the original schedule due to the impact of COVID-19. Project status, challenges and outstanding issues will be discussed in this article. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXA02  
About • paper received ※ 21 May 2021       paper accepted ※ 09 June 2021       issue date ※ 11 August 2021  
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MOXB02 First Results of the IOTA Ring Research at Fermilab experiment, electron, optics, octupole 19
 
  • A. Valishev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, B.L. Cathey, S. Chattopadhyay, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A. Arodzero, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • D.L. Bruhwiler, J.P. Edelen, C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  • S. Chattopadhyay, S. Szustkowski
    Northern Illinois University, DeKalb, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • M. Hofer
    TU Vienna, Wien, Austria
  • M. Hofer, R. Tomás García
    CERN, Geneva, Switzerland
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  • K.-J. Kim
    ANL, Lemont, Illinois, USA
  • K.-J. Kim, Y.K. Kim, N. Kuklev, I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • T.V. Shaftan
    BNL, Upton, New York, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling and quantum science experiments. In this talk we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented will be the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXB02  
About • paper received ※ 20 May 2021       paper accepted ※ 02 July 2021       issue date ※ 23 August 2021  
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MOPAB035 Modified Lattice of the Compact Storage Ring in the cSTART Project at Karlsruhe Institute of Technology sextupole, quadrupole, octupole, storage-ring 159
 
  • A.I. Papash, E. Bründermann, B. Härer, A.-S. Müller, R. Ruprecht, J. Schäfer, M. Schuh
    KIT, Karlsruhe, Germany
  
  A very large acceptance compact storage ring (VLA-cSR) is under design at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT, Germany). The combination of a compact storage ring and a laser wakefield accelerator (LWFA) might be the basis for future compact light sources and advancing user facilities. Meanwhile, the post-LWFA beam should be adapted for storage and accumulation in a dedicated storage ring. Modified geometry and lattice of a VLA-cSR operating at 50 MeV energy range have been studied in detailed simulations. The main features of a new model are described here. The new design, based on 45° bending magnets, is suitable to store the post-LWFA beam with a wide momentum spread (1% to 2%) as well as ultra-short electron bunches in the fs range from the Ferninfrarot Linac- Und Test- Experiment (FLUTE). The DBA-FDF lattice with relaxed settings, split elements, and higher-order optics of tolerable strength allows improving the dynamic aperture to an acceptable level. This contribution discusses the lattice features in detail and different possible operation schemes of a VLA-cSR.  
poster icon Poster MOPAB035 [1.405 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB035  
About • paper received ※ 10 May 2021       paper accepted ※ 27 May 2021       issue date ※ 24 August 2021  
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MOPAB036 Different Operation Regimes at the KIT Storage Ring KARA (Karlsruhe Research Accelerator) operation, optics, electron, storage-ring 163
 
  • A.I. Papash, M. Brosi, E. Huttel, A. Mochihashi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale
    KIT, Karlsruhe, Germany
  
  The KIT storage ring KARA operates in a wide energy range from 0.5 to 2.5 GeV. Different operation modes have been implemented at KARA, so far, the double-bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, different versions of low-compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low-alpha optics has been simulated, tested and implemented in a wide operational range of the storage ring and is now routinely used at 1.3 GeV for studies of beam bursting effects caused by coherent synchrotron radiation in the THz frequency range. Different non-linear effects, in particular residual high-order components of the magnetic field, generated in high-field superconducting wigglers have been studied and cured. Based on good agreement between computer simulations and experiments, a new operation mode at high vertical tune was implemented. The beam performance during user operation as well as at low-alpha regimes has been improved. A specific optic with negative compaction factor was simulated, tested and is in operation.  
poster icon Poster MOPAB036 [1.477 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB036  
About • paper received ※ 13 May 2021       paper accepted ※ 08 June 2021       issue date ※ 29 August 2021  
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MOPAB038 Robustness Studies and First Commissioning Simulations for the SOLEIL Upgrade Lattice alignment, sextupole, MMI, simulation 171
 
  • D. Amorim, A. Loulergue, L.S. Nadolski, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  
  Diffraction limited light sources will use very strong focusing elements to achieve their emittance goal. The beam will therefore be more sensitive to magnet field and alignment errors. Impact of errors on the lattice proposed for the SOLEIL upgrade was studied with the Accelerator Toolbox (AT) code. The performance achieved with the imperfect lattice will be presented. In particular the effect of girders misalignment was also accounted for. As the lattice uses a large number of permanent magnets for the beam bending as well as the focusing, challenges arise in terms of beam correction. The correctors and BPMs location and number will be investigated to maximize their efficiency, and corrector magnet strength required to obtain a closed orbit will be studied. The commissioning strategy, and in particular the method used to achieve the first turns and a stored beam in the machine will also be exposed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB038  
About • paper received ※ 19 May 2021       paper accepted ※ 31 May 2021       issue date ※ 16 August 2021  
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MOPAB039 Amplitude-Dependent Shift of Betatron Tunes and Its Relation to Long-Term Circumference Variations at NSLS-II sextupole, simulation, closed-orbit, wiggler 175
 
  • L.H. Yu, G. Bassi, Y. Hidaka, B. Podobedov, V.V. Smaluk, G.M. Wang, X. Yang
    BNL, Upton, New York, USA
  
  The comparison of amplitude tune dependence measured for NSLSII lattices with models indicated the large change of amplitude tune dependence over time apparently can not be solely explained by magnets variation or beta function changes, but it seems can be explained by energy changes. On the other hand, the energy change required by fitting with the amplitude tune dependence change is too large to be explained by the RF frequency change and the change of the sum of correctors in the period of the measurements. To explain this apparent contradiction, our analysis shows the long term storage ring circumference change can explain the apparent energy change. Our data indeed shows a seasonal change of the amplitude tune dependence over long term observation. This clearly also indicated a relation to long term closed orbit drift. Hence the current work indicates a new strategy to study how to use amplitude tune dependence as a guideline to analyze long term lattice parameter shifts and closed orbit drift, and improve the orbit and machine performance stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB039  
About • paper received ※ 09 May 2021       paper accepted ※ 26 May 2021       issue date ※ 26 August 2021  
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MOPAB041 Convergence Map with Action-Angle Variables Based on Square Matrix for Nonlinear Lattice Optimization linear-dynamics, resonance, 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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MOPAB043 Validation of APS-U Beam Dynamics Using 6-GeV APS Beam HOM, simulation, cavity, impedance 189
 
  • L. Emery, P.S. Kallakuri, R.R. Lindberg, A. Xiao
    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.
Several beam measurements at the Advanced Photon Sources were done with a lowered-energy beam of 6 GeV in order to verify or validate calculation codes and some predictions for the APS-U. Though the APS lattice is obviously different from that of the APS-U some aspects of the beams at 6 GeV are similar, for example, the synchrotron radiation damping rate. At 6 GeV, one can also store more current and run with a higher rf bucket allowing the characterization of larger momentum aperture lattices. We report measurements (or plans of measurements) on general instabilities thresholds, lifetime, and other subtle effects. The important topic of ion instabilities at 6 GeV is covered in a separate paper by J. Calvey at this conference. 		 
poster icon Poster MOPAB043 [0.829 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB043  
About • paper received ※ 20 May 2021       paper accepted ※ 23 June 2021       issue date ※ 10 August 2021  
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MOPAB048 Robust Design and Control of the Nonlinear Dynamics for BESSY-III controls, optics, sextupole, synchrotron 209
 
  • J. Bengtsson, M. Abo-Bakr, P. Goslawski, A. Jankowiak, B.C. Kuske
    HZB, Berlin, Germany
  
  The design philosophy for a robust prototype lattice design for BESSY III, i.e., that is insensitive to small parameter changes, e.g. engineering tolerances - based on a higher-order-achromat, a la: SLS, NSLS-II, MAX IV, and SLS 2 - is outlined & presented. As usual, a well optimized design requires a clear understanding of the end-user requirements and close collaboration between the linear optics designer and nonlinear dynamics specialist for a systems approach.  
poster icon Poster MOPAB048 [1.202 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB048  
About • paper received ※ 17 May 2021       paper accepted ※ 24 May 2021       issue date ※ 27 August 2021  
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MOPAB052 Study of Beam Transmission Efficiency in Injection and Ramping Process of the HEPS Booster booster, injection, simulation, storage-ring 225
 
  • Y.M. Peng, Z. Duan, Y. Jiao, C. Meng
    IHEP, Beijing, People’s Republic of China
  
  A high-bunch-charge mode, with a bunch charge of approximately 14.4 nC at 200 mA, has been proposed for the storage ring of High Energy Photon Source (HEPS). In order to reduce the bunch charge requirement to the injector, high-energy accumulation in the HEPS booster is proposed to combine with the on-axis swap-out injection. This allows reducing the requirement of bunch charge accelerated in HEPS booster (500 MeV-6 GeV) from over 14.4 nC to about 5 nC. It is expected that the overall transmission efficiency during the low energy injection and ramping process of the booster should be higher than 80% to fulfill the requirement. In this paper, we present the simulation results of transmission efficiency and potential improvement measures.  
poster icon Poster MOPAB052 [0.362 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB052  
About • paper received ※ 13 May 2021       paper accepted ※ 26 May 2021       issue date ※ 15 August 2021  
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MOPAB053 Progress of Lattice Design and Physics Studies on the High Energy Photon Source storage-ring, injection, booster, impedance 229
 
  • Y. Jiao, Y. Bai, X. Cui, C.C. Du, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, S.C. Jiang, B. Li, C. Li, J.Y. Li, N. Li, X.Y. Li, P.F. Liang, C. Meng, W.M. Pan, Y.M. Peng, Q. Qin, H. Qu, S.K. Tian, J. Wan, B. Wang, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
    IHEP, Beijing, People’s Republic of China
  • X.H. Lu
    IHEP CSNS, Guangdong Province, People’s Republic of China
  
  Funding: Work supported by High Energy Photon Source (HEPS), a major national science and technology infrastructure and NSFC (11922512)
The High Energy Photon Source (HEPS) is a 34-pm, 1360-m storage ring light source being built in the suburb of Beijing, China. The HEPS construction started in mid-2019. While the physics design has been basically determined, modifications on the HEPS accelerator physics design have been made since 2019, in order to deal with challenges emerging from the technical and engineering designs. In this paper, we will introduce the new storage ring lattice and injector design, and also present updated results of related physics issues, including impedance and collective effects, lattice calibration, insertion device effects, injection design studies, etc. 		 
poster icon Poster MOPAB053 [0.699 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB053  
About • paper received ※ 10 May 2021       paper accepted ※ 24 May 2021       issue date ※ 17 August 2021  
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MOPAB059 Tools for Use of Generalized Gradient Expansions in Accelerator Simulations dipole, simulation, septum, quadrupole 253
 
  • M. Borland, R.R. Lindberg, R. Soliday, A. Xiao
    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.
A common assumption in simulation of accelerators is that the magnets can be approximated using a hard-edge model, perhaps with some edge effects implemented in an impulse approximation. This is usually a good assumption but ignores details of the longitudinal variation of the magnetic fields, which makes it straightforward to implement symplectic tracking. Use of generalized gradient expansions* provides an alternative approach that can suppress numerical deficiencies that may be present in computed or measured 3D field maps. However, the computation of the expansions is not particularly straightforward. In this note, we describe several recently-developed tools that make this process fairly painless and allow tracking with such expansions in the program ELEGANT**. We show several examples of using the tools for simulations related to the Advanced Photon Source Upgrade.
* M. Venturini et al., NIM A 427, 387 (1999).
** M. Borland, Advanced Photon Source LS-287, September 2000 		 
poster icon Poster MOPAB059 [4.311 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB059  
About • paper received ※ 17 May 2021       paper accepted ※ 26 May 2021       issue date ※ 18 August 2021  
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MOPAB061 Comparison Simulation Results of the Collimator Aperture in HEPS Storage Ring simulation, ECR, storage-ring, scattering 257
 
  • Y.L. Zhao, Y. Jiao, N. Li
    IHEP, Beijing, People’s Republic of China
  
  The High Energy Photon Source (HEPS) is a 6 GeV diffraction-limited storage ring light source, which is under construction and planned to be in operation in 2025. To protect the sensitive elements from being damaged and reduce the radiation level of the site, collimators will be installed in the storage ring to localize the particle losses. The Touschek scattering is the main cause of particle losses during daily nominal operations. Based on the elegant simulations, we evaluate the physical design of the collimators, especially analysis the collimator performance with different collimator apertures. The simulation results will be introduced in this paper.  
poster icon Poster MOPAB061 [0.701 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB061  
About • paper received ※ 13 May 2021       paper accepted ※ 17 August 2021       issue date ※ 21 August 2021  
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MOPAB062 A Single Dipole Source for Broad-Band Soft Photon Beamlines in Diamond-II dipole, emittance, dynamic-aperture, linear-dynamics 261
 
  • M. Apollonio, G. Cinque, H. Ghasem, A.N. Jury, I.P.S. Martin, R. Rambo
    DLS, Oxfordshire, United Kingdom
  
  Diamond-II is a project based at Diamond Light Source for an upgrade towards a Storage Ring characterized by a reduction of a factor 20 in its natural emittance and a doubling of the number of straight sections. At Diamond-II the majority of existing beamline capacity should be maintained, while enhancing their performance thanks to the increase in brightness at the source points. The substantial modification of the lattice imposes a likewise re-design of the broad-band sources, presently based on standard dipoles. In this paper we discuss a possible solution for the IR/THz beamline B22 operating within a photon energy range between 1meV and 1eV. This proposal, ideal for low critical energy and single source point sources, entails the insertion of a dipole in one of the newly created mid-cell straights of the machine, while reducing the bending power of the nearby gradient dipoles. After performing the linear matching of the lattice, reproducing a comparable phase advance in the modified cell, we studied the non-linear dynamics of the system. Comparison of the main observables (Dynamic Aperture, Injection Efficiency and Lifetime) with the baseline case is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB062  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 12 August 2021  
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MOPAB063 Commissioning Strategy for Diamond-II MMI, optics, quadrupole, storage-ring 265
 
  • M. Apollonio, R.T. Fielder, H. Ghasem, I.P.S. Martin
    DLS, Oxfordshire, United Kingdom
  
  At Diamond Light Source we are working on the upgrade towards a machine aimed at a factor 20 reduction in emittance and an increase of the capacity for beamlines. Crucially the success of the programme depends on the ability to inject and capture the electrons in the storage ring, and finally reach control of beam alignment and the linear optics. The paper presents the series of strategies adopted to achieve the commissioning of the machine, from the threading procedure ensuring the first turn of the electron beam, to the orbit corrections in the storage ring. Beam based alignment of the quadrupoles and skew quadrupoles is illustrated and restoration of the linear optics (LOCO) for the storage ring is presented. Main performance parameters (Dynamic Apertures, Injection Efficiency and Lifetime) are calculated to evaluate the performance of the commissioned lattices.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB063  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 14 August 2021  
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MOPAB065 Optimization of the Lattice Replacement Options for the Next Generation Australian Synchrotron emittance, synchrotron, storage-ring, sextupole 269
 
  • R. Auchettl, R.T. Dowd, Y.E. Tan
    AS - ANSTO, Clayton, Australia
  
  The design of a next generation Australian Synchrotron replacement lattice is a multi-objective and multi-constrained problem. Our group was tasked to produce a low emittance design while re-using the existing tunnel infrastructure and injector system. Our objectives coupled with the set infrastructure constraints are not straightforward to achieve with manual design. Several variables act at cross-purposes to one-another, leading to a conflicting trade-off between objectives. Recently we have investigated replacement options for the Australian Synchrotron containing longitudinal gradient and reverse bends in the form of a 4BA (4-bend achromat) lattice. In this work, optimise the lattice design for a potential fourth generation Australian Synchrotron facility. We outline the baseline 4BA solution to the lowest emittance lattice that can reuse the existing tunnels and injector system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB065  
About • paper received ※ 19 May 2021       paper accepted ※ 28 May 2021       issue date ※ 19 August 2021  
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MOPAB066 Dual Octupole Emittance Growth Correction of the CompactLight XFEL Bunch Compressors octupole, emittance, FEL, linac 272
 
  • R. Auchettl, R.T. Dowd
    AS - ANSTO, Clayton, Australia
  
  An optimized CompactLight X-Ray Free Electron Laser (FEL) bunch compressor design is presented. In this work, we insert an octupole into the center of the two sequential bunch compressors. We show how this scheme can adjust the compression, while correcting the undesirable peak current profile and emittance growth.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB066  
About • paper received ※ 24 May 2021       paper accepted ※ 28 May 2021       issue date ※ 24 August 2021  
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MOPAB073 Beam Loss Simulations During Beam Dumping in Heps kicker, simulation, dumping, photon 294
 
  • X. Cui, Y. Jiao, Y.L. Zhao
    IHEP, Beijing, People’s Republic of China
  
  The High Energy Photon Source (HEPS) is a 6 GeV storage ring light source under construction in China. Several collimators installed in the vacuum chamber will be used as beam dump in the storage ring operation. Preliminary simulations showed that the temperature rise caused by the beam power deposited on the collimators will far exceed the melting point of the collimator material. In order to cure this problem, special kickers are proposed to be installed in the ring to modulate the beam during beam dumping, thereby increasing the size of the beam hit on the collimators. In this article, some simulation results of the density of particles on the collimators during beam dumping for different HEPS lattice and different kicker parameters are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB073  
About • paper received ※ 17 May 2021       paper accepted ※ 07 June 2021       issue date ※ 31 August 2021  
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MOPAB074 Preliminary Study of Design Method for Hybrid MBA Lattice resonance, 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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MOPAB075 Proposal of the Southern Advanced Photon Source and Current Physics Design Study photon, linac, storage-ring, emittance 300
 
  • S. Wang, J. Chen, L. Huang, Y. Jiao, B. Li, Z.P. Li, W. Liu, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  • Y. Han, X.H. Lu, Y. Zhao
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • X. Liu
    Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
  
  It has been considered to build a mid-energy fourth-generation storage ring light source neighbouring the China Spallation Neutron Source, in Guangdong Province, the south of China. The light source is named the Southern Advanced Photon Source (SAPS). Preliminary physics design studies on the SAPS have been implemented for a few years. In this paper, we will describe considerations of technical roadmap and key parameter choice for this light source, and introduce the up-to-date lattice designs and related physics studies on the SAPS.  
poster icon Poster MOPAB075 [1.689 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB075  
About • paper received ※ 12 May 2021       paper accepted ※ 20 May 2021       issue date ※ 21 August 2021  
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MOPAB089 Effect of Different Models of Combined-function Dipoles on the HEPS Parameters dipole, storage-ring, quadrupole, emittance 335
 
  • Y.Y. Guo, Y. Jiao, N. Li
    IHEP, Beijing, People’s Republic of China
  
  The high energy photon source (HEPS) is a 6 GeV, kilometer-scale storage ring light source being built in Beijing, China. In the current ring lattice, the combined-function dipoles are used and assumed to have constant dipole field. However, in the actual magnet design, an eccentrically placed quadrupole is adopted, in which the bending field along the trajectory is not constant. In this paper, we will present the effect of the two models of combined-function dipoles on the parameters of the storage ring.  
poster icon Poster MOPAB089 [0.590 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB089  
About • paper received ※ 13 May 2021       paper accepted ※ 25 May 2021       issue date ※ 27 August 2021  
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MOPAB095 Concept Design for the CLS2 Accelerator Complex electron, emittance, storage-ring, synchrotron 354
 
  • M.J. Boland, P.J. Hunchak
    University of Saskatchewan, Saskatoon, Canada
  • C.K. Baribeau, D. Bertwistle, J.M. Patel, H. Shaker, X. Shen, M.J. Sigrist
    CLS, Saskatoon, Saskatchewan, Canada
  • F. Le Pimpec
    EuXFEL, Schenefeld, Germany
  • E.J. Wallén
    LBNL, Berkeley, California, USA
  
  The Canadian Light Source has been in operation since 2005 and is now looking at a design concept to upgrade to a fourth generation storage ring. A brief overview is given of a possible accelerator complex layout, including some details on the lattice design and injection system. A full energy linac is being explored as an option for top-up injection and to future proof the facility for a potential FEL upgrade in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB095  
About • paper received ※ 23 May 2021       paper accepted ※ 28 July 2021       issue date ※ 13 August 2021  
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MOPAB096 Rocking Curve Imaging Experiment at SSRL 10-2 Beamline photon, wiggler, experiment, radiation 357
 
  • A. Halavanau, R. Arthur, B. Johnson, J.P. MacArthur, G. Marcus, R.A. Margraf, Z. Qu, T. Rabedeau, T. Sato, C.J. Takacs, D. Zhu
    SLAC, Menlo Park, California, USA
  
  Stanford Synchrotron Radiation Lightsource (SSRL) serves a wide scientific community with its variety of X-ray capabilities. Recently, we have employed a wiggler source located at beamline 10-2 to perform high resolution rocking curve imaging (RCI) of diamond and silicon crystals. In-house X-ray RCI capability is important for the upcoming cavity-based x-ray source development projects at SLAC, such as cavity-based XFEL (CBXFEL) and X-ray laser oscillator (XLO). In this proceeding, we describe theoretical considerations, and provide experimental results, validating the design of our apparatus. We also provide a plan for future improvements of the RCI@SSRL program.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB096  
About • paper received ※ 19 May 2021       paper accepted ※ 27 July 2021       issue date ※ 10 August 2021  
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MOPAB102 CSR Impedance in HEPS Storage Ring impedance, storage-ring, synchrotron, vacuum 379
 
  • H.S. Xu, X.Y. Li, N. Wang
    IHEP, Beijing, People’s Republic of China
  
  High Energy Photon Source (HEPS) is under construction in Beijing, China. The relatively complete impedance model has been built up based on the element-by-element impedance calculation. However, Coherent Synchrotron Radiation (CSR) impedance, which might affect the longitudinal performance of the beam, was not included in the impedance model of the HEPS storage ring in the preliminary design stage. For completeness, we would like to take the CSR impedance into consideration. The most important contributions to the total CSR impedance come from the bending magnets and insertion devices. We therefore calculate the CSR impedance from both above mentioned elements in HEPS storage ring. The influence of the CSR impedance on the microwave instability threshold is studied and presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB102  
About • paper received ※ 17 May 2021       paper accepted ※ 18 June 2021       issue date ※ 27 August 2021  
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MOPAB106 Enhancing the MOGA Optimization Process at ALS-U with Machine Learning dynamic-aperture, emittance, sextupole, storage-ring 387
 
  • Y. Lu, M.P. Ehrlichman, T. Hellert, S.C. Leemann, H. Nishimura, C. Sun, M. Venturini
    LBNL, Berkeley, California, USA
  
  Funding: This research is funded by the US Department of Energy(BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The bare lattice optimization for the linear and nonlinear ALS-U storage ring lattice, even without reverse bending, comprises 11 degrees of freedom (DoF) and is therefore a very complex and highly time-consuming process. This design process relies heavily on multi-objective genetic algorithms (MOGA), usually requiring many months of experienced scientists’ time. The main problem lies in having to evaluate numbers of candidate lattices due to the stochastic process of MOGA. Although almost all of these candidates are eventually rejected, they nevertheless require extensive particle tracking to arrive at a Pareto front. We therefore propose a novel Machine Learning (ML) pipeline that nonlinear tracking is replaced by two well-trained neural networks (NNs) to predict dynamic aperture (DA) and momentum aperture (MA) for any lattice candidate. Initial training of these models takes only several minutes on conventional CPUs while predictions are then rendered near instantaneously. We present this novel method and demonstrate the resulting orders of magnitude speedup of the ML-enhanced MOGA process on a 2-DoF problem as well as first results on a more complex 11-DoF problem. 		 
poster icon Poster MOPAB106 [0.918 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB106  
About • paper received ※ 19 May 2021       paper accepted ※ 01 June 2021       issue date ※ 18 August 2021  
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MOPAB109 A Lattice for PETRA IV Based on the Combination of Different Arc Cell Designs undulator, sextupole, emittance, resonance 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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MOPAB110 An Electron Synchrotron Lattice Based on Theoretic Minimal Emittance Cell emittance, extraction, sextupole, synchrotron 403
 
  • H.C. Chao
    DESY, Hamburg, Germany
  
  A design of an electron synchrotron featuring the theoretic minimal emittance (TME) cells is presented. It has 32 superperiods and the circumference is around 300 m. It offers versatile functions with the equilibrium emittance less than 10 nm-rad at 6 GeV. The beam energy can go up to 7 GeV. Locations with proper phase advances are found to form effective vertical orbit bumps, which can be used for the injections and extraction. A tune scan study shows the sweet spot for the working point. Some discussions of other usages and studies of synchro-betatron coupling effects are also included in this article.  
poster icon Poster MOPAB110 [0.777 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB110  
About • paper received ※ 11 May 2021       paper accepted ※ 28 May 2021       issue date ※ 30 August 2021  
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MOPAB112 A Modified Hybrid 6BA Lattice for the HALF Storage Ring emittance, damping, storage-ring, SRF 407
 
  • Z.H. Bai, G.Y. Feng, T.L. He, W. Li, W.W. Li, G. Liu, Z.L. Ren, L. Wang, P.H. Yang, S.C. Zhang, T. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  In this paper, we propose a modified hybrid 6BA lattice as the baseline lattice of the Hefei Advanced Light Facility (HALF) storage ring. Similar to the Diamond-II lattice, the proposed lattice cell has one long straight section and one mid-straight section; but the two bend units adjacent to the mid-straight are LGB/RB units (LGB: longitudinal gradient bend, RB: reverse bend), which can give both lower emittance and shorter damping times. The designed HALF storage ring, with an energy of 2.2 GeV and 20 lattice cells, has a natural emittance of about 85 pm·rad.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB112  
About • paper received ※ 15 May 2021       paper accepted ※ 20 May 2021       issue date ※ 01 September 2021  
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MOPAB113 A Low-emittance Booster Lattice Design for the SOLEIL Upgrade booster, emittance, storage-ring, linear-dynamics 410
 
  • M.-A. Tordeux, A. Loulergue, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  • Z.H. Bai, G. Liu, T. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  The SOLEIL storage ring upgrade will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, the present booster also needs to be upgraded, aiming to reduce the emittance below 10 nm·rad. A multi-bend achromat lattice is designed in this context for the booster upgrade, which consists of two superperiods to respect the present race-track configuration. The lattice is a 16BA HOA (Higher-Order Achromat) type lattice, composed of 14 unit cells, 2 matching cells and a long straight section, and combined-function bending magnets are used in the unit cells to both save space and reduce the emittance. The natural emittance of the designed booster is 5.2 nm·rad at the final energy of 2.75 GeV. This paper presents the general constraints, linear lattice design and nonlinear dynamics optimization for the booster upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB113  
About • paper received ※ 19 May 2021       paper accepted ※ 28 May 2021       issue date ※ 26 August 2021  
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MOPAB119 Comparisons Between AT and Elegant Tracking closed-orbit, simulation, dynamic-aperture, emittance 432
 
  • G. Penn, T. Hellert, M. Venturini
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DEAC02-05CH11231.
The simulation codes Elegant* and Accelerator Toolbox (AT)** are both in common use for the study of particle accelerators and light sources. They use different software platforms and have different capabilities, so there is a strong motivation to be able to switch from one version to another to achieve different goals. In addition, it is useful to directly compare results for benchmarking studies. We discuss differences in tracking methods and results for various elements, and explore the impact on simulations performed with lattices designed for the ALS-U. In addition to single-particle tracking, global properties such as chromaticity, dynamics aperture, momentum aperture and beam lifetime are also investigated. We have also developed scripts to translate AT lattices into elegant lattice files to facilitate comparisons.
* M. Borland, Advanced Photon Source LS-287, September 2000.
** A. Terebilo, Particle Accelerators Conference 2001, p. 3203. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB119  
About • paper received ※ 20 May 2021       paper accepted ※ 31 May 2021       issue date ※ 30 August 2021  
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MOPAB126 BESSY III & MLS II - Status of the Development of the New Photon Science Facility in Berlin undulator, radiation, photon, emittance 451
 
  • P. Goslawski, M. Abo-Bakr, F. Andreas, M. Arlandoo, J. Bengtsson, V. Dürr, K. Holldack, J.-G. Hwang, A. Jankowiak, B.C. Kuske, J. Li, A.N. Matveenko, T. Mertens, A. Meseck, E.C.M. Rial, M. Ries, M.K. Sauerborn, A. Schälicke, M. Scheer, P. Schnizer, L. Shi, J. Viefhaus
    HZB, Berlin, Germany
  • J. Lüning
    UPMC, Paris, France
  
  HZB operates and develops two synchrotron radiation sources at Berlin Adlershof. The larger one, BESSY II with an energy of 1.7 GeV and 240 m circumference is optimized for soft-X rays and in operation since 1999. The smaller one is the MLS (Metrology Light Source), owned by the Physikalische Technische Bundesanstalt (PTB) - Germany’s National Metrology Institute. It is designed to fulfill the special metrology needs of the PTB with an energy of 0.6 GeV and 48 m circumference, covering the spectral range from THz and IR to EUV/VUV. In 2020 a discussion process has been started to define the requirements for successors of BESSY II and MLS and to study the possibilities integrate them into a new photon science facility in Berlin Adlershof. Here, we give a status report and present a first envisaged parameter space to both machines (see also MOPAB262, MOPAB220, MOPAB048, MOPAB242).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB126  
About • paper received ※ 18 May 2021       paper accepted ※ 24 June 2021       issue date ※ 18 August 2021  
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MOPAB127 Construction of an Impedance Model for Diamond-II impedance, simulation, dipole, cavity 455
 
  • R.T. Fielder, T. Olsson
    DLS, Oxfordshire, United Kingdom
  
  Impedance models for accelerators have traditionally been presented in a static form, usually as tables or spreadsheets which must be read manually. As part of the Diamond-II upgrade work, we have developed an impedance model using a lattice structure. This allows more direct integration with simulation codes while keeping important information easily human readable. We present here a description of this implementation method, along with an overview of the Diamond-II impedance model derived from the latest engineering design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB127  
About • paper received ※ 18 May 2021       paper accepted ※ 20 May 2021       issue date ※ 11 August 2021  
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MOPAB131 Synchrotron SOLEIL Upgrade Project emittance, photon, vacuum, injection 463
 
  • A. Nadji
    SOLEIL, Gif-sur-Yvette, France
  
  To remain competitive in the future, SOLEIL is also working on an upgrade project plan based on Multi-Bend Achromat (MBA) lattices. The Technical Design Report of the project is expected to start in early 2021 immediately after the completion of the Conceptual Design Report (CDR) phase. The achieved equilibrium emittance in the CDR reference lattice (80 pm-rad) is about 50 times smaller than that of the existing storage ring (4000 pm-rad). By operating on a linear coupling resonance, round beam sizes in Insertion Devices straight sections of less than 10 microns RMS in both planes can be produced. These performances rely on the use of a 10 mm inner diameter circular copper vacuum chamber with NEG-coating allowing reaching strong quadrupole gradients and very strong sextupole and octupole strengths. As all these technical challenges are pushing the engineering technology to the limits, they are being investigated through an intensive R&D program based on extensive numerical simulations, prototyping, and measurement with the beam. Extensive use of the pure permanent magnet technology beyond what has been done so far in the other similar projects is considered in this project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB131  
About • paper received ※ 22 May 2021       paper accepted ※ 27 July 2021       issue date ※ 30 August 2021  
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MOPAB182 Automated Synchrotron Lattice Design and Optimisation Using a Multi-Objective Genetic Algorithm network, synchrotron, dipole, superconducting-magnet 616
 
  • X. Zhang, S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
  • E. Benedetto
    TERA, Novara, Italy
  • E. Benedetto
    CERN, Meyrin, Switzerland
  
  Funding: This work is partially supported by the Australian Government Research Training Program Scholarship.
As part of the Next Ion Medical Machine Study (NIMMS), we present a new method for designing synchrotron lattices. A step-wise approach was used to generate random lattice structures from a set of feedforward neural networks. These lattice designs are optimised by evolving the networks over many iterations with a multi-objective genetic algorithm (MOGA). The final set of solutions represent the most effi- cient and feasible lattices which satisfy the design constraints. It is up to the lattice designer to choose a design that best suits the intended application. The automated algorithm presented here randomly samples from all possible lattice layouts and reaches the global optimum over many iterations. The requirements of an efficient extraction scheme in hadron therapy synchrotrons impose stringent constraints on the lat- tice optical functions. Using this algorithm allows us to find the global optimum that is tailored to these constraints and to fully utilise the flexibilities provided by new technology. 		 
poster icon Poster MOPAB182 [6.006 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB182  
About • paper received ※ 15 May 2021       paper accepted ※ 23 June 2021       issue date ※ 14 August 2021  
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MOPAB185 HL-LHC Local Linear Optics Correction at the Interaction Regions quadrupole, optics, interaction-region, simulation 628
 
  • H. Garcia Morales
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • J.F. Cardona
    UNAL, Bogota D.C, Colombia
  • R. Tomás García
    CERN, Geneva, Switzerland
  
  Magnetic imperfections of the HL-LHC inner triplet are expected to generate a significant \beta-beating. For that reason, improved local optics correction techniques at the low-\beta insertions is essential to ensure a high luminosity performance in the HL-LHC. In this study, we compare different strategies for local optics correction at the Interaction Regions with respect to their final performance in terms of residual \beta-beating. Supervised learning techniques are also explored to predict the inner triplet magnetic error contributions.  
poster icon Poster MOPAB185 [0.469 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB185  
About • paper received ※ 14 May 2021       paper accepted ※ 10 June 2021       issue date ※ 31 August 2021  
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MOPAB191 Method Development for Cavity Failure Compensation in a Superconducting Linac cavity, linac, emittance, ECR 647
 
  • F. Bouly
    LPSC, Grenoble Cedex, France
  
  Reliability is a major challenge within the perspective of improving the performances and sustainability of MegaWatt class accelerators. To optimize the operational costs of such accelerators the availability requirements are becoming more and more challenging. These requirements are even more stringent in the case of Accelerator Driven systems (ADS). As an example, for the MYRRHA (Multipurpose Hybrid Research Reactor for High-tech Applications) ADS demonstrator, the actual availability limit is set to a maximum of 10 beam interruptions (longer than 3 seconds) over a 3-month operating cycle. For this purpose, the accelerator design is based on a redundant and fault-tolerant scheme to enable rapid mitigation of a cavity failure. The adopted strategy is to apply for local compensation: a failed cavity is compensated by several neighboring cavities. Beam dynamics studies and method developments to apply such a failure compensation scheme are here reviewed. First simulation results for superconducting linac retuning and potential future improvements will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB191  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 20 August 2021  
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MOPAB214 Linear Optics Measurement for the APS Ring with Turn-by-Turn BPM Data optics, quadrupole, betatron, storage-ring 707
 
  • X. Huang, V. Sajaev, Y.P. Sun, A. Xiao
    ANL, Lemont, Illinois, USA
  
  We measure the linear optics of the APS storage ring from turn-by-turn BPM data taken when the beam is excited with an injection kicker. Decoherence due to chromaticity and amplitude-dependent detuning is observed and compared to theoretic predictions. Independent component analysis is used to analyze the data, which separates the betatron normal modes and synchrotron motion, despite contamination of bad BPMs. The beta functions and phase advances are subsequently obtained. The method is used to study the linear optics perturbation of an insertion device.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB214  
About • paper received ※ 12 May 2021       paper accepted ※ 09 June 2021       issue date ※ 01 September 2021  
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MOPAB216 20-24 GeV FFA CEBAF Energy Upgrade linac, booster, optics, emittance 715
 
  • S.A. Bogacz, J.F. Benesch, R.M. Bodenstein, B.R. Gamage, G.A. Krafft, V.S. Morozov, Y. Roblin
    JLab, Newport News, Virginia, USA
  • J.S. Berg, S.J. Brooks, D. Trbojevic
    BNL, Upton, New York, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177
A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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MOPAB220 Towards Deterministic Design of MBA-Lattices dipole, emittance, quadrupole, sextupole 722
 
  • B.C. Kuske
    HZB, Berlin, Germany
  
  Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
Since the pioneering work of MAX IV *, multi-bend achromat (MBA) lattices have become the standard in lattice design for 4th generation lights sources as well as upgrades of 3rd generation storage rings. The distribution of the bending angle to many weak dipoles enables to reach unprecedented low emittance and highest brightness. In their most basic form, MBA-lattices consist of a repetitive unit cell and two identical matching cells on either end of the achromatic arc. The simplicity of both cells allows for a unique determination of the linear lattice parameters in dependence on boundary conditions defined by the design goals. Those might be the emittance, momentum compaction factor, chromaticity, as well as phase advances with respect to achieving higher-order achromatic structures. A scan of optional lattice prototypes is quickly obtained. We demonstrate this concept and apply it in the design of the first candidates for the lattice of BESSY III, a green-field 4th generation storage ring being currently planned at HZB, Berlin, Germany.
* https://www.maxiv.lu.se/accelerators-beamlines/accelerators/accelerator-documentation/max-iv-ddr/ 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB220  
About • paper received ※ 17 May 2021       paper accepted ※ 23 July 2021       issue date ※ 26 August 2021  
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MOPAB224 Optimization and Error Studies for the USSR HMBA Lattice injection, SRF, booster, dynamic-aperture 730
 
  • L. Hoummi, N. Carmignani, L.R. Carver, S.M. Liuzzo, T.P. Perron, S.M. White
    ESRF, Grenoble, France
  • I.A. Ashanin, S.M. Polozov
    MEPhI, Moscow, Russia
  • T. Kulevoy
    ITEP, Moscow, Russia
  • T. Kulevoy
    NRC, Moscow, Russia
  
  Several new accelerator facilities will be built in Russia in the next few years. One of those facilities is a 6 GeV storage ring (SR) light source, the Ultimate Source of Synchrotron Radiation (USSR) to be built in Protvino, near Moscow. The Cremlin+ project aims to incorporate in this activity the best experience of European Accelerator Laboratories. The optimization of such optics including realistic errors and a commissioning-like sequence of corrections, using Multi-Objective Genetic Algorithms (NSGA-II) is presented. Several corrections schemes are also tested.  
poster icon Poster MOPAB224 [1.164 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB224  
About • paper received ※ 12 May 2021       paper accepted ※ 01 June 2021       issue date ※ 13 August 2021  
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MOPAB225 A HMBA Lattice Design Study for the 4 GeV Light Source storage-ring, emittance, dipole, sextupole 734
 
  • S.W. Jang, E.-S. Kim
    KUS, Sejong, Republic of Korea
  
  The 4th generation storage ring (4GSR) project will start from 2022 in South Korea. We proposed HMBA (Hybrid Multi-Bend Achromatic) lattice for 4GSR with super-bend at the center of the lattice. The 4GSR lattice is designed to combined HMBA lattice with a 4 GeV, 53 pm-rad emittance and 843m. The storage ring including 32 long with 5.65m, 16 short straight with 1.3m sections for IDs and 16 super-bend sections for more different type of beam line experiments. A calculated dynamic aperture is more larger than 15mm in both direction and the beam life time is expected to 4.7 hour. In this paper, we will describe the study results of the HMBA lattice design with a 4GeV light source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB225  
About • paper received ※ 20 May 2021       paper accepted ※ 24 May 2021       issue date ※ 30 August 2021  
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MOPAB242 A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring quadrupole, storage-ring, emittance, dipole 782
 
  • J. Li, M. Abo-Bakr, P. Goslawski
    HZB, Berlin, Germany
  • Z.H. Bai
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242  
About • paper received ※ 18 May 2021       paper accepted ※ 09 June 2021       issue date ※ 17 August 2021  
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MOPAB248 Injection Schemes for the SOLEIL Upgrade injection, storage-ring, betatron, synchrotron 796
 
  • M.-A. Tordeux, P. Alexandre, R. Ben El Fekih, P. Brunelle, L. Hoummi, A. Loulergue, L.S. Nadolski, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  
  Injection into the SOLEIL upgrade storage ring is much more challenging compared to the case of the current ring. Thanks to the experience gained in the development, manufacture and commissioning of a Multipole Injection Kicker (MIK) on the MAX IV 3 GeV storage ring, the SOLEIL pulsed magnet team is currently developing new MIK magnets that will serve as the basis for the injection schemes in the upgrade storage ring. We then propose two kinds of injections: firstly, a betatron off-axis injection that should be compatible with the full-coupling storage ring tuning, and secondly, a synchrotron on-axis injection by creating a large horizontal dispersion bump at the injection point.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB248  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 26 August 2021  
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MOPAB253 Comparison of Transfer Map Derivation Methods for Static Magnetic Fields multipole, quadrupole, extraction, operation 799
 
  • J.A. Crittenden, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811.
We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253  
About • paper received ※ 19 May 2021       paper accepted ※ 18 June 2021       issue date ※ 13 August 2021  
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MOPAB261 NSLS-II Storage Ring Lattice Analysis using Response Matrices quadrupole, alignment, storage-ring, sextupole 829
 
  • J. Choi
    BNL, Upton, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy (DOE) under contract No. DE-SC0012704.
Affected from various sources, the NSLS-II storage ring lattice is slightly changing operation to operation and, for the operational performance, we are continually optimizing the lattice and maintaining the response matrices for the feedback and lattice analysis. Because not all sources are identified, we are investing efforts to identify as many as possible. As one of such efforts, we also study the measured response matrices. In this paper, we present the results of lattice studies using a pair of recently measured response matrices. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB261  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 19 August 2021  
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MOPAB262 First Thoughts on Lattices for a possible Metrology Light Source 2 emittance, dipole, sextupole, radiation 833
 
  • M. Arlandoo, M. Abo-Bakr, P. Goslawski, J. Li
    HZB, Berlin, Germany
  
  The Physikalisch-Technische Bundesanstalt (PTB), in cooperation with the Helmholtz-Zentrum Berlin (HZB), operates the Metrology Light Source (MLS), which is a low-energy electron storage ring. The MLS can be operated in a low-alpha mode to produce coherent synchroton ration in the far-IR and THz spectral range. In the scope of the Conceptual Design process for a BESSY II successor, the PTB also requested for an MLS successor to cover their increasing demands on synchrotron radiation. A combination of two different machines, one optimized for low emittance (BESSY III) and one for flexible timing capabilities (MLS II), would provide best radiation capabilities for our user community. In this paper, we discuss the demands on the MLS II and propose first lattice candidates which may meet the needs of the PTB and HZB. Currently, we focus on linear lattices for standard user mode with first steps towards nonlinear optimization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB262  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 17 August 2021  
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MOPAB263 Preliminary Beam Dynamics Studies for 200 MeV Superconducting Linac Planned at KOMAC linac, proton, DTL, radiation 837
 
  • S. Lee, J.J. Dang, H.S. Kim, H.-J. Kwon
    Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
  • Y.-S. Cho
    KAERI, Daejon, Republic of Korea
  
  Funding: This work has been supported through KOMAC operation fund of KAERI by the Korea government (MSIT).
Korea Multi-purpose Accelerator Complex (KOMAC) is planning an energy upgrade of the existing 100 MeV proton linac to 200 MeV using a superconducting Half Wave Resonator (HWR) operating at 350 MHz. A cryomodule is planned to house four HWR cavities with a warm doublet focusing lattice structure. Matching between the already existing DTL section and HWR section is designed and studied. We report the preliminary study of the beam dynamics of the 200 MeV superconducting linac carried out at KOMAC. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB263  
About • paper received ※ 20 May 2021       paper accepted ※ 01 July 2021       issue date ※ 24 August 2021  
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MOPAB295 Simulation Study of Emittance Measurement Using a Genetic Algorithm for Space Charge Dominated Beams emittance, quadrupole, space-charge, simulation 935
 
  • H.D. Zhang, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 under and the STFC Cockcroft core grant No. ST/G008248/1.
The quadrupole scan method is one of the traditional ways to measure beam emittance in an accelerator. The required devices are simple: several quadrupole magnets and a beam profile monitor. Beam sizes are measured from the beam profile monitor with different quadrupole settings to bring the beam through its waist and then fitted to a quadratic equation to determine the Twiss parameters. measured data from a quadrupole scan taking the beam through its waist is fitted to a quadratic equation and this allows determining the Twiss parameters. However, with increasing beam intensity, the transfer function becomes non-linear and this causes a deviation of the fitted emittance from its real value, making it no longer useful. In this contribution, a genetic algorithm is applied to find the optimum quadrupole scan fit in space-charge dominated electron beams. Results from simulations using different space charge levels are presented and scenarios identified where this method can be applied. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB295  
About • paper received ※ 19 May 2021       paper accepted ※ 28 May 2021       issue date ※ 02 September 2021  
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MOPAB310 Vertical Phase Space Measurement Progress at Canadian Light Source electron, emittance, synchrotron, experiment 963
 
  • Y. Yousefi Sigari, D. Bertwistle, M.J. Boland
    CLS, Saskatoon, Saskatchewan, Canada
  • M.J. Boland
    University of Saskatchewan, Saskatoon, Canada
  
  A key feature of third-generation light sources is their small vertical opening angle, which is difficult to measure experimentally. To reconstruct the vertical phase space, one can scan the beam’s position using X-ray synchrotron radiation (XSR) and a pinhole camera. The XSR diagnostic beamline, operational in the wavelength region of 0.05 - 0.15 nm, in Canadian Light Source (CLS) is qualified to measure the beam position with X-ray radiation. Using the corrector magnets in CLS lattice made of 12 identical double-bend achromats (DBA) cells, vertical iterations can be executed parallel to the beam’s original orbit. The outcomes of this experiment are: 1) the vertical beam positions that are monitored by BPMs, and 2) the X-ray image of the beam that is projected through the pinhole. The bumps were simulated using Matlab Middle Layer (MML) for Accelerator control systems to get an insight of the source point’s position in the XSR’s bending magnet. The simulation shows the position of the source point depends on which corrector sets are chosen.  
poster icon Poster MOPAB310 [0.328 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB310  
About • paper received ※ 19 May 2021       paper accepted ※ 28 July 2021       issue date ※ 13 August 2021  
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TUXC06 Visualizing Lattice Dynamic Behavior by Acquiring a Single Time-Resolved MeV electron, laser, detector, experiment 1311
 
  • X. Yang, T.V. Shaftan, V.V. Smaluk, J. Tao, L. Wu, Y. Zhu
    BNL, Upton, New York, USA
  • W. Wan
    ShanghaiTech University, Shanghai, People’s Republic of China
  
  We explore the possibility of visualizing the lattice dynamic behavior by acquiring a single time-resolved MeV UED image. Conventionally, multiple UED shots with varying time delays are needed to map out the entire dynamic process. The measurement precision is limited by the timing jitter between the pulses of laser pump and UED probe. We show that, by converting the longitudinal time of an electron bunch to the transverse position of a Bragg peak on the detector, one can obtain the full lattice dynamic process in a single electron pulse. We propose a novel design of a time-resolved UED with the capability of capturing a wide range of dynamic features in a single diffraction image. The work presented here is not only an extension of the ultrashort-pulse pump/long-pulse probe scheme being used in transient spectroscopy studies for decades but also advances the capabilities of MeV UED for future applications with tunable electron probe profile and detecting time range with femtosecond resolution. Furthermore, we present numerical simulations illustrating the capability of acquiring a single time-resolved diffraction image based on the case-by-case studies of lattice dynamic behavior.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC06  
About • paper received ※ 14 May 2021       paper accepted ※ 28 July 2021       issue date ※ 31 August 2021  
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TUPAB003 Final Focus Solenoids Beam-Based Positioning Tests solenoid, alignment, collider, positron 1330
 
  • D.B. Shwartz
    BINP SB RAS, Novosibirsk, Russia
  • D.B. Shwartz
    NSU, Novosibirsk, Russia
  
  The final focusing at the VEPP-2000 electron-positron collider is done by 13 T superconducting solenoids. The misalignment of solenoids not only provides closed orbit distortions but also harmful for dynamic aperture reduction due to strong nonlinear fringe fields. The final beam-based alignment of solenoids was foreseen but turned out to be not a trivial procedure. Here we present the test study of solenoids positioning reconstruction procedure based on circulating beam orbit responses.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB003  
About • paper received ※ 22 May 2021       paper accepted ※ 02 June 2021       issue date ※ 28 August 2021  
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TUPAB004 Comparison of Accelerator Codes for Simulation of Lepton Colliders radiation, emittance, optics, lepton 1334
 
  • L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
  
  This paper compares simulation results obtained with SAD, MAD-X and the PTC implementation in MADX for the design studies of the FCC-ee. On-momentum and off-momentum optics are explored for the various programs. Particle tracking with and without synchrotron radiation are used to compare amplitude detuning and emittance. Finally, this paper outlines how well-established SAD features such as tapering have recently been integrated into MADX.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB004  
About • paper received ※ 16 May 2021       paper accepted ※ 15 June 2021       issue date ※ 26 August 2021  
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TUPAB007 A Correction Scheme for the Magnet Imperfection on the CEPC Collider Ring quadrupole, emittance, alignment, optics 1346
 
  • B. Wang, Y. Wang, Y. Wei, C.H. Yu, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  
  This paper describes the error correction scheme for the CEPC CDR lattice in Higgs mode, which has a small beta function at the interaction point. The low emittance optics has an enhanced sensitivity to the magnet misalignments and field errors, especially for the final focus quadrupole misalignment. The magnet imperfection will cause the closed orbit distortion and optics distortion. The correction scheme for these magnet imperfections includes the closed orbit correction, the dispersion correction, the beta function correction and the betatron coupling correction. The resulting performance and the dynamic aperture for the corrected lattice are studied.  
poster icon Poster TUPAB007 [1.075 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB007  
About • paper received ※ 14 May 2021       paper accepted ※ 09 June 2021       issue date ※ 14 August 2021  
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TUPAB008 Progress of the First-Turn Commissioning Simulations for HEPS simulation, quadrupole, MMI, dipole 1349
 
  • B. Wang, Z. Duan, D. Ji, Y. Jiao, Y.L. Zhao
    IHEP, Beijing, People’s Republic of China
  
  The High Energy Photon Source (HEPS) is 6 GeV, kilometer-scale, 4th generation storage ring light source. The lattice has an ultralow emittance and strong focusing such that the beam dynamics is very sensitive to the magnet misalignments and other error sources. Getting the first turn and establishing the closed orbit is essential for accelerator commissioning. This paper describes a simulation algorithm for achieving the first turn commission based on the latest HEPS storage ring lattice. We developed a new accelerator toolbox (AT)-based program for automatic optimizing the first turn commissioning. The algorithm and simulation results will be presented in this paper.  
poster icon Poster TUPAB008 [0.646 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB008  
About • paper received ※ 14 May 2021       paper accepted ※ 11 June 2021       issue date ※ 28 August 2021  
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TUPAB023 Design Considerations of a High Intensity Booster for PETRA IV injection, emittance, booster, extraction 1386
 
  • H.C. Chao, I.V. Agapov, S.A. Antipov
    DESY, Hamburg, Germany
  
  A 6 GeV booster lattice with a high intensity capacity for the PETRA IV project is presented. Firstly the requirements and constraints are articulated. Due to the geometric constraints the ring will be installed in racks mounted on ceilings. Then following some design strategies of reaching high intensity limit, a lattice is designed and presented. The topics covering the linear optics, nonlinear dynamics, orbit correction, orbit bump, and some instability studies are investigated.  
poster icon Poster TUPAB023 [0.975 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB023  
About • paper received ※ 11 May 2021       paper accepted ※ 11 June 2021       issue date ※ 12 August 2021  
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TUPAB024 Lattice Options Comparison for a DLSR Injector emittance, injection, booster, synchrotron 1390
 
  • H.C. Chao, I.V. Agapov, S.A. Antipov
    DESY, Hamburg, Germany
  
  DESY IV, as a part of the injector chain, must have lower emittance for PETRA IV injection. Depending on the scenarios of the injector, two lattice options for DESY IV are presented. They are designed for different purposes. The first option comes with a high momentum compaction factor with acceptable emittance. It is designed to be a full intensity booster. The other option is with low emittance dedicated to be an accumulator at high energies. The general beam dynamics properties are simulated and discussed. Their strengths and weaknesses are compared.  
poster icon Poster TUPAB024 [0.751 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB024  
About • paper received ※ 11 May 2021       paper accepted ※ 09 June 2021       issue date ※ 31 August 2021  
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TUPAB048 HMBA Optics Correction Experience at ESRF optics, MMI, closed-orbit, SRF 1462
 
  • S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Farvacque, T.P. Perron, P. Raimondi, S.M. White
    ESRF, Grenoble, France
  
  The ESRF-EBS storage ring, successfully commissioned in 2020, operates the HMBA lattice, first proposed in * and then adopted in several recent upgrade programs. The successful and timely commissioning of the storage is in large part due to the excellent optics control achieved over that period. Design performance were obtained with lower than predicted correction strengths, localized for the most part in the vicinity of sextupoles. This remarkable behavior is not only the result of the corrective actions taken during the commissioning but also of the extremely accurate conception and alignment of the machine. This report summarizes the steps that lead to the present performances and discusses their stability over time.
* J.Biasci et al. Synchrotron Radiation News27, 8 (2014), https://doi.org/10.1080/08940886.2014.970931. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB048  
About • paper received ※ 10 May 2021       paper accepted ※ 11 June 2021       issue date ※ 20 August 2021  
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TUPAB049 USSR HMBA Storage Ring Lattice Options injection, emittance, SRF, optics 1466
 
  • S.M. Liuzzo, N. Carmignani, L.R. Carver, J. Chavanne, L. Hoummi, J. Jacob, T.P. Perron, R. Versteegen, S.M. White
    ESRF, Grenoble, France
  • I.A. Ashanin, V.S. Dyubkov, S.M. Polozov
    MEPhI, Moscow, Russia
  • I.A. Ashanin, V.S. Dyubkov, T. Kulevoy, S.M. Polozov
    NRC, Moscow, Russia
  • T. Kulevoy
    ITEP, Moscow, Russia
  
  Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution #287
Several new accelerator facilities will be built in Russia in a few years from now. One of those facilities is a 6GeV storage ring (SR) light source (USSR - Ultimate Source of Synchrotron Radiation) to be built in Protvino, near Moscow. The Cremlin+ project aims to incorporate in this activity the best experience of European Accelerator Laboratories. The design of the optics for this SR is presented here in two declinations leading to 70 pm-rad equilibrium horizontal emittance. The first is a 40 cells lattice, the second is the same but includes high field Short Bending magnet sources in each cell. Optics and high order multipole optimizations are performed to obtain sufficient lifetime and dynamic aperture for a conservative off-axis injection. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB049  
About • paper received ※ 12 May 2021       paper accepted ※ 11 June 2021       issue date ※ 21 August 2021  
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TUPAB050 A Long Booster Option for the USSR 6 GeV Storage Ring booster, storage-ring, injection, optics 1470
 
  • S.M. Liuzzo, N. Carmignani, L.R. Carver, L. Hoummi, T.P. Perron, R. Versteegen, S.M. White
    ESRF, Grenoble, France
  • I.A. Ashanin, S.M. Polozov
    MEPhI, Moscow, Russia
  • I.A. Ashanin, T. Kulevoy, S.M. Polozov
    NRC, Moscow, Russia
  • T. Kulevoy
    ITEP, Moscow, Russia
  
  Funding: European Union’s Horizon 2020 research and innovation program under grant #871072 Russian federation resolution no. 287
The design of the optics of a full length 6 GeV booster for the USSR (Ultimate Source of Synchrotron Radiation) are presented. This option already followed with success by other laboratories, would allow to obtain a small emittance injected beam thus enabling smooth top-up operation. Details of the design inspired by the ESRF DBA lattice and the possible operating modes are described. The transfer lines booster to storage ring are also addressed in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB050  
About • paper received ※ 12 May 2021       paper accepted ※ 11 June 2021       issue date ※ 24 August 2021  
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TUPAB052 Current Study of Applying Machine Learning to Accelerator Physics at IHEP network, electron, target, photon 1477
 
  • J. Wan, Y. Jiao
    IHEP, Beijing, People’s Republic of China
  
  Funding: National Natural Science Foundation of China(No.11922512), Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201904) and National Key R&D Program of China(No.2016YFA0401900).
In recent years, machine learning (ML) has attracted increasing interest among the accelerator field. As a complex collection of multiple physical subsystems, the design and operation of an accelerator can be very nonlinear and complicated, while ML is taken as a powerful tool to solve such nonlinear and complicated problems. In this study, we report on several successful applications of ML to accelerator physics at IHEP. The nonlinear dynamics optimization of the High Energy Photon Source (HEPS) that is a 4th-generation light source is a challenging topic. In this optimization, we use a ML surrogate model to fast select the potentially competitive solutions for a multiobjective genetic algorithm that can significantly improve the convergence rate and the diversity among obtained solutions. Besides, we also tried to apply a generative adversarial net to solve one-to-many problems of longitudinal beam current profile shaping. Unlike most supervised machine learning methods than cannot learn one-to-many maps, the generative adversarial net-based method is able to predict multiple solutions instead of one for a 4-dipole chicane to realize several desired custom current profiles. 		 
poster icon Poster TUPAB052 [0.913 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB052  
About • paper received ※ 11 May 2021       paper accepted ※ 21 June 2021       issue date ※ 27 August 2021  
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TUPAB054 CDR BASELINE LATTICE FOR THE UPGRADE OF SOLEIL emittance, injection, photon, coupling 1485
 
  • A. Loulergue, D. Amorim, P. Brunelle, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  
  Previous MBA studies converged toward a lattice composed of 20 7BA solution elaborated by adopting the sextupole pairing scheme with dispersion bumps originally developed at the ESRF-EBS. It provided a low natural horizontal emittance value of 70-80 pm-rad range at an energy of 2.75 GeV. Due to difficulties to accommodate such lattice geometry in the SOLEIL present tunnel as well as to preserve at best the beamline positioning, alternative lattice based on HOA (Higher-Order Achromat) type cell has been recently investigated. The HOA type cell being more modular and possibly exhibiting larger momentum acceptance as well as low emittances, a solution alternating 7BA and 4BA cells was then identified as the best to adapt the current beamline positioning. The SOLEIL CDR upgrade reference lattice is then composed of 20 HOA cells alternating 7BA and 4BA giving a natural horizontal emittance of 80 pm-rad. The linear and non-linear beam dynamic properties of the lattice along with the possibility of horizontal off-axis injection at full betatron coupling are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB054  
About • paper received ※ 21 May 2021       paper accepted ※ 02 July 2021       issue date ※ 10 August 2021  
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TUPAB062 Expediting APS-U Long-Term Particle Tracking with Arbitrary Order Taylor Map simulation, damping, collective-effects, resonance 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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TUPAB175 ESSnuSB Linac and Transfer Line: Lattice Design and Error Studies linac, dipole, proton, DTL 1805
 
  • N. Blaskovic Kraljevic, M. Eshraqi, B.T. Folsom
    ESS, Lund, Sweden
  
  Funding: ESSnuSB has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 777419.
The ESS neutrino superbeam (ESSnuSB) project is being studied as an upgrade to the European Spallation Source (ESS). This proposed upgrade consists of adding an H− source to the existing beamline in order to send H− pulses in between proton pulses, effectively doubling the beam power from 5 MW to 10 MW. In this contribution, we present the 2.5 GeV linear accelerator (linac) lattice and the design of the transfer line from the linac to the accumulator ring, where pulses would be stacked to achieve short proton pulses of high intensity. The results of error studies, quantifying the effect of accelerator imperfections and H− ion stripping losses on the beam transport through the linac and transfer line, are also presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB175  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 31 August 2021  
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TUPAB208 FETS-FFA Ring Study injection, optics, closed-orbit, proton 1901
 
  • J.-B. Lagrange, D.J. Kelliher, A.P. Letchford, S. Machida, C.R. Prior, C.T. Rogers
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • S.J. Brooks
    BNL, Upton, New York, USA
  • C. Brown
    Brunel University, Middlesex, United Kingdom
  • J. Pasternak
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • E. Yamakawa
    JAI, Egham, Surrey, United Kingdom
  
  ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK, providing a proton beam with a power of 0.2~MW. Detailed studies are under way for a major upgrade, including the use of Fixed Field alternating gradient Accelerator (FFA). A proof-of-principle FFA ring, called FETS-FFA is planned to investigate the feasibility of this kind of machine for the required MW beam power. This paper discusses the study of the FETS-FFA ring case.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB208  
About • paper received ※ 19 May 2021       paper accepted ※ 08 July 2021       issue date ※ 14 August 2021  
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TUPAB209 The Particle Tracking Code Fixfield FFAG, quadrupole, acceleration, focusing 1905
 
  • J.-B. Lagrange
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 25 August 2021  
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TUPAB213 Important Drift Space Contributions to Non-Linear Beam Dynamics resonance, sextupole, 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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TUPAB214 Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis operation, synchrotron, storage-ring, closed-orbit 1917
 
  • J. Frank, M. Arlandoo, P. Goslawski, T. Mertens, M. Ries
    HZB, Berlin, Germany
  
  At HZB’s BESSY II and MLS facilities we have the ability to tune the momentum compaction factor α up to second non-linear order. The non-linear dependence α(δ) brings qualitative changes to the longitudinal phase space and introduces new fix points α(δ)=0 which produce the so-called α-buckets. We present with this paper an analysis of this phenomena from the standpoint of bifurcation theory. With this approach we were able to characterize the nature of the fix points and their position in direct dependence on the tunable parameters. Furthermore, we are able to place stringent conditions onto the tunable parameters to either create or destroy α-buckets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB214  
About • paper received ※ 12 May 2021       paper accepted ※ 17 June 2021       issue date ※ 26 August 2021  
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TUPAB215 Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment quadrupole, network, focusing, operation 1920
 
  • J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
    HZB, Berlin, Germany
  
  With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215  
About • paper received ※ 12 May 2021       paper accepted ※ 31 August 2021       issue date ※ 21 August 2021  
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TUPAB223 Design of Double- and Multi-Bend Achromat Lattices with Large Dynamic Aperture and Approximate Invariants sextupole, storage-ring, resonance, 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. 		 
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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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TUPAB227 Simultaneous Compensation of Phase and Amplitude Dependent Geometrical Resonances Using Octupoles octupole, sextupole, emittance, resonance 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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TUPAB228 IOTA Run 2 Beam Dynamics Studies in Nonlinear Integrable Systems optics, octupole, experiment, simulation 1964
 
  • N. Kuklev, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • S. Nagaitsev, A.L. Romanov, A. Valishev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by the U.S. NSF under award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy.
Nonlinear integrable optics is a promising design approach for suppressing fast collective instabilities. To study it experimentally, a new storage ring, the Integrable Optics Test Accelerator (IOTA), was built at Fermilab. IOTA has recently completed its second scientific run, incorporating many hardware and instrumentation improvements. This report presents the results of the two integrable optics experiments - the quasi-integrable Henon-Heiles octupole system and the fully integrable Danilov-Nagaitsev system. We demonstrate tune spread and dynamic aperture in agreement with tracking simulations, and a stable crossing of the integer resonance. Based on recovered single-particle phase space dynamics, we show improved invariant jitter consistent with intended effective Hamiltonian. We conclude by outlining future plans and efforts towards proton studies and larger designs. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB228  
About • paper received ※ 31 May 2021       paper accepted ※ 23 June 2021       issue date ※ 10 August 2021  
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TUPAB234 Exploring Accelerators for Intense Beams with the IBEX Paul Trap octupole, quadrupole, experiment, simulation 1980
 
  • J.A.D. Flowerdew
    University of Oxford, Oxford, United Kingdom
  • D.J. Kelliher, S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • S.L. Sheehy
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  
  Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234  
About • paper received ※ 19 May 2021       paper accepted ※ 18 June 2021       issue date ※ 12 August 2021  
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TUPAB235 Dynamic Aperture Optimization in the EIC Electron Storage Ring with Two Interaction Points electron, sextupole, collider, dynamic-aperture 1984
 
  • D. Marx, Y. Li, C. Montag, S. Tepikian, F.J. Willeke
    BNL, Upton, New York, USA
  • Y. Cai, Y.M. Nosochkov
    SLAC, Menlo Park, California, USA
  • G.H. Hoffstaetter, J.E. Unger
    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-SC0012704 and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
In the Electron-Ion Collider (EIC), which is currently being designed for construction at Brookhaven National Laboratory, electrons from the electron storage ring will collide with hadrons, producing luminosities up to 1034 cm-2 s-1. The baseline design includes only one interaction point (IP), and optics have been found with a suitable dynamic aperture in each dimension. However, the EIC project asks for the option of a second IP. The strong focusing required at the IPs creates a very large natural chromaticity (about -125 in the vertical plane for the ring). Compensating this linear chromaticity while simultaneously controlling the nonlinear chromaticity to high order to achieve a sufficient momentum acceptance of 1% (10 σ) at 18 GeV is a considerable challenge. A scheme to compensate higher-order chromatic effects from 2 IPs by setting the phase advance between them does not, by itself, provide the required momentum acceptance for the EIC Electron Storage Ring. A thorough design of the nonlinear optics is underway to increase the momentum acceptance using multiple sextupole families, and the latest results are presented here. 		 
poster icon Poster TUPAB235 [3.426 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB235  
About • paper received ※ 19 May 2021       paper accepted ※ 19 July 2021       issue date ※ 20 August 2021  
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TUPAB304 Preliminary Investigation of the Noises and Updates on Physics Studies of FOFB in HEPS power-supply, storage-ring, controls, factory 2197
 
  • X.Y. Huang, Y. Jiao, Y. Wei
    IHEP, Beijing, People’s Republic of China
  
  High Energy Photon Source (HEPS) is a Fourth-generation storage ring light source in China and is under construction. Noises, such as the ambient mechanical vibration and the power supply ripples of magnets, may induce large orbit motions of electron bunches and hence dramatically degrade the emitted photon beam quality. The effect of noises becomes significant and needs to be considered very carefully, especially when the emittances of the electron beam approach the diffraction limit of x-ray. For the HEPS, the noises are modelled and the total beam orbit motion is evaluated considering the spectral characteristics of all the transformation processes from the errors to the orbit. In this paper, we present the preliminary calculation of the effects of noises in HEPS, and the control of the orbit motion with the FOFB system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB304  
About • paper received ※ 17 May 2021       paper accepted ※ 02 July 2021       issue date ※ 16 August 2021  
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TUPAB365 Demonstration of ‘ZEPTO’ Permanent Magnet Technology on Diamond Light Source quadrupole, permanent-magnet, vacuum, radiation 2370
 
  • A.R. Bainbridge, B.J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • N. Krumpa
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • I.P.S. Martin, W. Tizzano
    DLS, Oxfordshire, United Kingdom
  
  The use of permanent magnets (PM’s) in place of traditional electromagnets is becoming more common in accelerator systems around the world. This change is being driven by the desire to reduce both the energy costs and carbon footprint of accelerators. However, the problem remains that it is difficult to adjust the field strength of PM systems. STFC and CERN have a longstanding collaboration in the Zero-Power Tuneable Optics (ZEPTO) project which aims to develop PM systems that are tuneable via moving the PM blocks within a static pole structure. This collaboration has previously produced 3 prototype magnets (2 quadrupoles and 1 dipole) for the proposed CLIC accelerator and aims to expand suitability to a variety of accelerators. We are now demonstrating this technology on a real machine by installing a ZEPTO magnet on Diamond Light Source. We outline the design, construction, and improvement of this technology demonstrator, highlighting the innovations over previous generations of ZEPTO technology that account for previously observed drawbacks.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB365  
About • paper received ※ 18 May 2021       paper accepted ※ 22 June 2021       issue date ※ 12 August 2021  
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TUPAB368 Design of the Longitudinal Gradient Dipole Magnets for HALF dipole, permanent-magnet, storage-ring, emittance 2378
 
  • M.Y. Mingyao
    Wang, Hefei, People’s Republic of China
  • G.Y. Feng, Z.L. Ren, H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  Hefei Advanced Light Facility (HALF) is the fourth generation diffraction-limited storage ring light source project in China. The lattice of the storage ring consists of six different dipoles with longitudinal gradients. The longitudinal-gradient dipoles (LGBs) are permanent magnets. This paper presents the designed construction of LGBs and the magnetic field results using OPERA3D. By optimizing the shape of the polar surface, the magnetic field uniformity is optimized to about 5×10-4. With some movable adjusting block, the magnetic field can be controlled accurately. The temperature stability of the magnet is better than 0.0074 T*mm/°C by setting temperature compensating shunt.  
poster icon Poster TUPAB368 [0.862 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB368  
About • paper received ※ 15 May 2021       paper accepted ※ 02 June 2021       issue date ※ 10 August 2021  
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WEXA04 The RCS Design Status for the Electron Ion Collider resonance, electron, injection, 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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WEPAB011 Update on the Low Emittance Tuning of the e+/e- Future Circular Collider alignment, emittance, sextupole, quadrupole 2601
 
  • T.K. Charles
    The University of Liverpool, Liverpool, United Kingdom
  • B.J. Holzer, F. Zimmermann
    CERN, Geneva, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
  
  The FCC-ee project studies the design of a future 100 km e+/e circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 1035 cm-2 s−1. To achieve ultra-low vertical emittance a highly effective emittance tuning scheme is required. In this paper, we describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB011  
About • paper received ※ 18 May 2021       paper accepted ※ 23 June 2021       issue date ※ 02 September 2021  
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WEPAB028 MAD-X for Future Accelerators solenoid, radiation, simulation, collider 2664
 
  • T.H.B. Persson, H. Burkhardt, L. Deniau, A. Latina, P.K. Skowroński
    CERN, Geneva, Switzerland
  
  The feasibility and performance of the future accelerators must, to a large extent, be predicted by simulation codes. This implies that simulation codes need to include effects that previously played a minor role. For example, in large electron machines like the FCC-ee the large energy variation along the ring requires that the magnets strength is adjusted to the beam energy at that location, normally referred to as tapering. In this article, we present new features implemented in the MAD-X code to enable and facilitate simulations of future colliders.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB028  
About • paper received ※ 17 May 2021       paper accepted ※ 06 July 2021       issue date ※ 27 August 2021  
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WEPAB033 Lattice Design of the CEPC Collider Ring for a High Luminosity Scheme luminosity, collider, dynamic-aperture, quadrupole 2679
 
  • Y. Wang, S. Bai, J. Gao, B. Wang, D. Wang, Y. Wei, J. Wu, C.H. Yu, J.Y. Zhai, Y. Zhang, Y.S. Zhu
    IHEP, Beijing, People’s Republic of China
  • Y. Zhang
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
  
  A high luminosity scheme of the CEPC has been proposed aiming to increase the luminosity mainly at Higgs and Z modes. In this paper, the high luminosity scheme will be introduced briefly, including the beam parameters and RF staging. Then, the lattice design of the CEPC collider ring for the high luminosity scheme will be presented, including the bare lattice design and dynamic aperture optimization at Higgs energy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB033  
About • paper received ※ 20 May 2021       paper accepted ※ 05 July 2021       issue date ※ 27 August 2021  
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WEPAB074 A Distributed Sextupoles Lattice for the ALBA Low Emittance Upgrade emittance, sextupole, injection, optics 2762
 
  • G. Benedetti, M. Carlà, U. Iriso, Z. Martí, F. Pérez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  The first lattice studied in 2019 for the ALBA upgrade was a 7BA lattice with two dispersion bumps, for localised chromatic correction. That lattice had limited dynamic aperture and momentum acceptance. In 2020 we started to explore a different approach to find an MBA lattice with distributed chromatic correction that meets the same emittance goal with larger dynamic aperture and momentum acceptance. The choice of the number of bendings per cell, as well as the tuning of the magnet gradients, is carried out by developing a light weight solver that performs both the emittance and chromaticity optimisation of the arcs and the matching of the linear optics in the straight sections. We present the status of the storage ring upgrade studies, the performance of the new developed lattice, together with the issues related with the injection scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB074  
About • paper received ※ 19 May 2021       paper accepted ※ 16 June 2021       issue date ※ 22 August 2021  
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WEPAB089 Conceptual Design of Booster Synchrotron for Siam Photon Source II booster, synchrotron, dipole, focusing 2795
 
  • S. Krainara, S. Klinkhieo, P. Klysubun, T. Pulampong, P. Sudmuang
    SLRI, Nakhon Ratchasima, Thailand
  
  Funding: Synchrotron Light Research Institute (Public organization)
A project on a 3.0 GeV Siam Photon Source II (SPS-II) has been started. The storage ring of SPS-II was designed to obtain an electron beam with a low-emittance below 1 nm-rad. The SPS-II injector mainly consists of a 150 MeV linac and a full-energy booster synchrotron. The booster synchrotron will be installed in the same tunnel as the storage ring, with a total circumference of 304.829 meters. The proposed lattice of the booster contains 40 modified FODO cells with combined function magnets. This lattice achieves a small beam emittance less than 10 nm-rad at 3 GeV, which can provide a high injection efficiency for top-up operation. The conceptual design for SPS-II booster synchrotron is presented in this work. 		 
poster icon Poster WEPAB089 [1.187 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB089  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 24 August 2021  
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WEPAB102 Half-Metal Spin Filter for Highly Polarized Emission from GaAs Photocathodes electron, polarization, cathode, hardware 2833
 
  • S. Poddar, C.-J. Jing, E.J. Montgomery
    Euclid Beamlabs, Bolingbrook, USA
  • P. Lukashev
    University of Northern Iowa, Cedar Falls, Iowa, USA
  • C. Palmstrøm
    UCSB, Santa Barbara, California, USA
  • M.L. Stutzman, S. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by Department of Energy grant number DE-SC0020564.
GaAs-based photocathodes are one of the major sources of spin-polarized electrons and are crucial for the upcoming Electron-Ion collider experiments which includes study of proton spin and spin parity violation in the standard model. The theoretical polarization limit in unstrained GaAs photocathodes is 50 % but only 35 % is routinely achieved in experiments. Spin selective filtering allows to boost the spin polarization beyond the 50 % theoretical limit. In this work, first-principle electronic calculations using standard Density Functional Theory are performed to predict possible Heusler alloy half-metal candidates to be used as spin-filter. Simulations are also performed to investigate the half-metallicity as function of the magnetic spin direction. Several devices are experimentally fabricated using dedicated Molecular Beam Epitaxy growth system. We implemented Quantum Efficiency and Polarization testing of these half-metal/GaAs heterostructures using a dedicated Mott polarimeter system. Photoemission can also be seen on magnetically switching the spin-filter direction accompanied by a change in sign of the asymmetry which is a qualitative proof of the spin-filtering effect. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB102  
About • paper received ※ 20 May 2021       paper accepted ※ 28 July 2021       issue date ※ 27 August 2021  
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WEPAB119 Beam Injection with a Pulsed Nonlinear Magnet Into the HALF Storage Ring injection, storage-ring, dynamic-aperture, multipole 2878
 
  • G. Liu, W. Li, L. Wang, P.N. Wang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  The nonlinear optics of the HALF storage ring are well optimized to make it possible to inject the beam with the pulsed multipole injection scheme. In this paper, the injection scheme is studied with an innovatively designed pulsed nonlinear magnet. The layout and parameters of the injection system are well designed based on the acceptance analysis. The injection process is simulated with particle tracking is presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB119  
About • paper received ※ 20 May 2021       paper accepted ※ 29 July 2021       issue date ※ 13 August 2021  
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WEPAB157 Understanding the Growth Dynamics Cs-Sb Thin Films via In-Situ Characterization Techniques: Towards Epitaxial Alkali Antimonide Photocathodes electron, cathode, brightness, scattering 2979
 
  • A. Galdi, I.V. Bazarov, L. Cultrera, J.M. Maxson
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J. Balajka, W.J.I. DeBenedetti, M. Hines, C. Hu, L. Moreschini, H. Paik, C.T. Parzyck, K.M. Shen
    Cornell University, Ithaca, New York, USA
  
  Funding: National Science Foundation award PHY-1549132, the Center for Bright Beams and PARADIM, Cooperative Agreement No.DMR-1539918.
Alkali antimonide photocathodes, such as Cs3Sb, have attractive properties, such as low emittance and high quantum efficiency, which makes them excellent candidates for next-generation high-brightness electron sources. A large number of studies in literature focus on quantum efficiency and lifetime, and fewer report chemical and structural analysis, despite the latter ultimately determine the brightness at the photocathode. Epitaxial, single-crystalline films would allow to study the intrinsic properties of alkali antimonide photocathodes and to optimize them for maximum brightness, but this goal remains elusive. A strong limiting factor is the extreme air sensitivity, preventing ex-situ structural and chemical analysis. We report a study on the growth of Cs-Sb films via molecular beam epitaxy with reflection high-energy electron diffraction to monitor the growth in real time. The samples were characterized via in-situ ultraviolet photoelectron spectroscopy, x-ray photoelectron spectroscopy and scanning tunneling microscopy. Cs3Sb and CsSb phases can be stabilized on appropriate single crystal substrates, with the latter reproducibly resulting in atomically smooth surfaces. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB157  
About • paper received ※ 19 May 2021       paper accepted ※ 30 June 2021       issue date ※ 10 August 2021  
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WEPAB169 Towards Ultra-Smooth Alkali Antimonide Photocathode Epitaxy cathode, interface, emittance, electron 3001
 
  • E.J. Montgomery
    Private Address, Bolingbrook, USA
  • O. Chubenko, G.S. Gevorkyan, S.S. Karkare, P. Saha
    Arizona State University, Tempe, USA
  • R.G. Hennig, J.T. Paul
    University of Florida, Gainesville, Florida, USA
  • C. Jing, S. Poddar
    Euclid Beamlabs, Bolingbrook, USA
  • H.A. Padmore
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by Department of Energy, Office of Science, Office of Basic Energy Sciences, under grant number DE-SC0020575.
Photocathodes lead in brightness among electron emitters, but transverse momenta are unavoidably nonzero. Ultra-low transverse emittance would enable brighter, higher energy x-ray free-electron lasers (FEL), improved colliders, and more coherent, detailed ultrafast electron diffraction/microscopy (UED/UEM). Although high quantum efficiency (QE) is desired to avoid laser-induced nonlinearities, the state-of-the-art is 100 pC bunches from copper, 0.4 mm-mrad emittance. Advances towards 0.1 mm-mrad require ultra-low emittance, high QE, cryo-compatible materials. We report efforts towards epitaxial growth of cesium antimonide on lattice matched substrates. DFT calculations were performed to downselect from a list of candidate lattice matches. Co-evaporations achieving >3% QE at 532 nm followed by atomic force and Kelvin probe microscopy (AFM and KPFM) show ultra-low 313 pm rms (root mean square) physical and 2.65 mV rms chemical roughness. We simulate roughness-induced mean transverse energy (MTE) to predict <1 meV from roughness effects at 10 MV/m in as-grown optically thick cathodes, promising low emittance via epitaxial growth. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB169  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 11 August 2021  
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WEPAB211 Lattice Design of the Beam Transfer Line (BTL) from PIP-II LINAC to the Booster at Fermilab booster, dipole, septum, power-supply 3120
 
  • M. Xiao
    Fermilab, Batavia, Illinois, USA
  
  PIP-II beam transfer line (BTL) to transport the beam from PIP-II Linac to the Booster ring at Fermilab. The latest design eliminates rolling the dipoles in the beam line to cross over the Tevatron tunnel. Also re-designed is the lattice in the region of the Booster Injection to meet the request of the civil construction needs and accommodate the constrains of the Booster injection request. A beam line to the beam absorber (BAL) is designed based on the request from the results of Mars simulations and ANASYS calculation of the absorber. Simulations with dipole and quadrupole field errors for the Beam Transport Line (BTL) to the Booster, which provides the specifications for all the magnets and Power supplies, will be presented too.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB211  
About • paper received ※ 20 May 2021       paper accepted ※ 08 July 2021       issue date ※ 31 August 2021  
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WEPAB263 Complex Unit Lattice Cell for Low-Emittance Synchrotrons sextupole, emittance, focusing, synchrotron 3254
 
  • Z.L. Ren, Z.H. Bai, J.J. Tan, L. Wang, H. Xu, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  To reach the real diffraction-limited emittance, it is generally required to increase the number of bends in multi-bend achromat (MBA) lattices that are used in the designs of fourth-generation synchrotron light sources. For an MBA lattice with distributed chromatic correction, more bends mean much tighter space and much stronger magnets. Inspired by the hybrid MBA lattice concept, in this paper we propose a new lattice concept called complex unit lattice cell, which can save space and reduce magnet strengths. A 17BA lattice based on the complex unit cell concept is designed for a 3 GeV synchrotron light source with a circumference of 537.6 m, which reaches a natural emittance of about 21 pm·rad. Comparison is also made between this 17BA lattice and the 17BA lattice with distributed chromatic correction to demonstrate the merit of the complex unit cell concept.  
poster icon Poster WEPAB263 [1.279 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB263  
About • paper received ※ 16 May 2021       paper accepted ※ 02 July 2021       issue date ※ 12 August 2021  
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WEPAB264 MOGA Optimization of Superconducting Longitudinal Gradient Bend Based on NbTi Wire solenoid, emittance, storage-ring, radiation 3257
 
  • C. Chen, Z.H. Bai, G.Y. Feng, Z.L. Ren, Zh.X. Tang, L. Wang, H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  Funding: Work supported by National Key Research and Development Program of China, (2016YFA0402001)
Multi-bend achromat lattices with unit cells have been used in diffraction-limited storage ring designs. The longitudinal gradient bend can reduce the horizontal emittance below the theoretical minimum of a given magnet structure, and generally the horizontal emittance reduces with the peak field grows. Therefore superconducting longitudinal gradient bend (SLGB) can produce higher peak field value and quasi-hyperbolic field profile to minimize emittance at location of radiation and generate better hard X-rays. NbTi conductor, rather than Nb3Sn conductor, is selected to keep the design and manufacture of SLGB magnet as simple as possible. In this paper, how the field profiles of race-track type coil and solenoid coil change with their geometric parameters is studied, and multi-objective genetic algorithm is used to optimize SLGB magnet structure considering Hefei Advanced Light Facility lattice design demand and NbTi critical current. 		 
poster icon Poster WEPAB264 [1.476 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB264  
About • paper received ※ 14 May 2021       paper accepted ※ 05 July 2021       issue date ※ 14 August 2021  
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WEPAB280 Two-Dimensional Beam-Beam Invariant with Applications to HL-LHC optics, resonance, closed-orbit, 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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WEPAB319 Open XAL Status Report 2021 framework, quadrupole, status, controls 3421
 
  • N. Milas, J.F. Esteban Müller, E. Laface, Y. Levinsen
    ESS, Lund, Sweden
  • T.V. Gorlov, A.P. Shishlo, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  
  The Open XAL accelerator physics software platform is being developed through international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general-purpose accelerator applications). This paper discusses progress in beam dynamics simulation, new RF models, and updated application framework along with new generic accelerator physics applications. We present the current status of the project, a roadmap for continued development, and an overview of the project status at each participating facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB319  
About • paper received ※ 19 May 2021       paper accepted ※ 21 July 2021       issue date ※ 11 August 2021  
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WEPAB360 Future Prospective for Bent Crystals in Accelerators collimation, scattering, experiment, SRF 3545
 
  • M. Romagnoni
    INFN-Ferrara, Ferrara, Italy
  • M. Romagnoni
    Universita’ degli Studi di Milano, Milano, Italy
  
  Super magnet dipoles employed to steer high energy particle beams are massive instruments requiring cryogenic cooling and featuring large energy consumption. A bent crystal has the potential in a few millimeters to deflect 100-1000 GeV particle beams as much as an hundreds-tesla magnetic dipole. Indeed, within the lattice of a crystal, large electric fields up to several GeV/cm are present. Positive charged particles can be efficiently channeled between two adjacent lattice planes, thus following their curvature. These features and the possibility to selectively affect only the portion of the beam intercepting the crystal led to the proposal of exploiting bent crystals for several purposes, such as the collimation of ions at LHC. In this scheme, the particles on the beam halo instead of being scattered by tens-centimeters long collimators are directly separated from the beam using a 4 mm long silicon crystal. The production of a bent crystal suitable for installation in the LHC beamline requires strict control over lattice features and bending apparatus. The results obtained by the years long research of the INFN research team in Ferrara are presented in this work.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB360  
About • paper received ※ 14 May 2021       paper accepted ※ 28 July 2021       issue date ※ 18 August 2021  
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WEPAB399 Applications of the Local Observable in Future Optics Measurements in HL-LHC and PETRA III optics, experiment, injection, quadrupole 3642
 
  • A. Wegscheider, R. Tomás García
    CERN, Meyrin, Switzerland
  
  Phase advances among four nearby beam position monitors in a circular accelerator can be used to calculate a local observable of quadrupolar lattice imperfections. This work explores the applicability of this local observable to two different circular accelerators: PETRA III, a synchrotron light source, and the LHC, a hadron collider as well as its upgrade project HL-LHC. MADX simulations for important optics settings are performed, showing that the local observable can detect strong error sources. This is of particular interest in important regions of the accelerators like the LHC’s interaction regions and PETRA III’s experimental hall.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB399  
About • paper received ※ 19 May 2021       paper accepted ※ 23 July 2021       issue date ※ 12 August 2021  
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THXB04 Non-Invasive Dispersion Function Measurement during Light Source Operations operation, synchrotron, storage-ring, emittance 3720
 
  • B. Podobedov, Y. Hidaka
    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.
We implemented a completely parasitic measurement of lattice dispersion functions in both horizontal and vertical planes, which is fully compatible with light source user operations. The measurement is performed by applying principal component analysis and adaptive filtering to very small residual orbit noise components introduced by the RF system and detected in the beam orbit data, sampled at 10 kHz. No changes in RF frequency are required. The measurement, performed once a minute, was shown to be robust and immune to changes in the beam current, residual orbit noise amplitude and frequency content as well as other factors. At low current it was shown to provide similar accuracy to the traditional method (which shifts the 500 MHz RF frequency by ±500 Hz). In this paper we will explain our measurement technique and present typical dispersion function stability achieved during NSLS-II operations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB04  
About • paper received ※ 26 June 2021       paper accepted ※ 13 July 2021       issue date ※ 23 August 2021  
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THPAB002 Lattice Design for BEPCII Upgrade cavity, quadrupole, dynamic-aperture, electron 3756
 
  • H. Geng, W.B. Liu, J. Qiu, J. Xing, C.H. Yu, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  
  The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high-energy physics study. Along with the deepening of the research, more important physics is expected in higher energy regions (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. In this paper, the lattice design for the upgrade of BEPCII is studied. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of the BEPCII beam with a reasonable margin.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB002  
About • paper received ※ 14 May 2021       paper accepted ※ 17 June 2021       issue date ※ 14 August 2021  
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THPAB016 Revisit of Nonlinear Dynamics in Hénon Map Using Square Matrix Method resonance, 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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THPAB022 Possibilities for Upgrading to Polarized SuperKEKB electron, polarization, experiment, cathode 3799
 
  • Z.J. Liptak, M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • J.M. Roney
    Victoria University, Victoria, B.C., Canada
  
  The SuperKEKB accelerator is currently in operation in Tsukuba, Japan, with a planned long shutdown in 2026. Among the possible upgrades being considered during this period is the change to a polarized electron beam in the High Energy Ring. Such a change would require modifications in the source generation and transport, geometrical and lattice variations to provide spin rotation, and polarimetry. A Polarized SuperKEKB Working Group has been formed from members of the Belle II experiment and the SuperKEKB accelerator team to investigate the possibilities and challenges of these modifications. This talk lays out the goals of the proposed upgrade, considers the necessary changes to the existing accelerator and their feasibility and lays out the physics motivation behind such an effort.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB022  
About • paper received ※ 19 May 2021       paper accepted ※ 23 July 2021       issue date ※ 29 August 2021  
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THPAB050 Compact Hybrid Planar Permanent Magnet Undulator Design for the APS Upgrade undulator, ECR, photon, permanent-magnet 3859
 
  • M. Abliz, M. Borland, J.H. Grimmer, J.S. Kerby, M. Ramanathan, A. Xiao
    ANL, Lemont, Illinois, USA
  
  We report on the successful design of a compact 28-mm period hybrid planar permanent magnet (HPPM) undulator for the Advanced Photon Source Upgrade (APS-U) project. The design produces a peak field of 9750 G at a gap of 8.5 mm, with a pole width reduced to 35 mm as compared to the planar undulators currently in use at the Advanced Photon Source. The design includes a detailed investigation into the origin of the HPPM undulator demagnetization. We report on a finding of an optimization method that reduces the demagnetization field and increases the field at the gap center of the design. It includes an optimization of the pole edges to increase the field and decrease roll-off in the transverse direction. Further design optimizations include analyses of the mechanical assembly tolerances and comparison with the original design before building the device. Beam physics analyses included kick-map analysis, dynamic acceptance (DA), local momentum acceptance (LMA), and Touschek lifetime of this design were performed with the 42-pm lattice of the APS-U. Detailed magnetic design, effective field, field roll-off, magnetic force, and tracking results are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB050  
About • paper received ※ 14 May 2021       paper accepted ※ 01 September 2021       issue date ※ 21 August 2021  
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THPAB073 Study of Seven-Bend-Achromat Lattice Option for Half emittance, storage-ring, octupole, sextupole 3926
 
  • J.H. Xu, Z.H. Bai, Z.L. Ren, J.J. Tan, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • Q. Zhang
    INEST, Hefei, People’s Republic of China
  
  A seven-bend-achromat (7BA) storage ring lattice design for Hefei Advanced Light Facility (HALF) with a beam energy of 2.2 GeV and a circumference of 388.8 m is presented. The 7BA lattice is designed with the combined function bends and reverse bends which has a natural emittance of about 67 pm·rad. Two lattice candidates with different tunes have been selected. One lattice has better nonlinear dynamic performance for off-axis injection. The other lattice provides lower beta functions at the center of straight sections. The results of these studies are discussed in this paper.  
poster icon Poster THPAB073 [1.146 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB073  
About • paper received ※ 15 May 2021       paper accepted ※ 28 July 2021       issue date ※ 16 August 2021  
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THPAB083 Measurement of the Longitudinal Phase-Space of the APS Photo-Injector Beam linac, cavity, gun, dipole 3963
 
  • Y. Sun
    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.
An S-band photo-cathode RF gun (PCG) exists at the front of the linac. The high-brightness photoinjector beam is accelerated by the linac and and can be used for accelerator technology and beam physics R&D experiments in the Linac Extension Area (LEA). For some applications, the beam needs to be compressed by a magnetic bunch compressor in the middle of the linac. An S-band transverse-mode cavity (Tcav) is available at the end of the linac for beam longitudinal phase-space diagnostics. Beam commissioning experience of the Tcav is reported in this paper. The cavity rf conditioning and calibration was performed. There is a horizontally bending dipole magnet downstream of the Tcav, which kicks beam in the vertical plane. Beam image on a YAG screen downstream of the Tcav and dipole magnet contains the single-shot information of the longitudinal phase-space of the photo-injector beam. The first measurements of the longitudinal phase-space of the compressed and non-compressed photoinjector beam are discussed. Improvements of the measurement resolution are planned. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB083  
About • paper received ※ 25 May 2021       paper accepted ※ 12 July 2021       issue date ※ 21 August 2021  
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THPAB089 Lattice Design for a Future Plan of UVSOR Synchrotron emittance, dynamic-aperture, optics, quadrupole 3970
 
  • E. Salehi, M. Katoh
    UVSOR, Okazaki, Japan
  • M. Katoh
    HSRC, Higashi-Hiroshima, Japan
  
  UVSOR is a 750 MeV synchrotron light source with a moderately small emittance of about 17nm. We surveyed the periodic solutions by drawing a tie diagram and mapped the emittance and the dynamic aperture on the tune diagram. The aim of this work is to search for a possible low emittance solution without a major change of the lattice. Although, we could not find a solution which has a drastically small emittance, we have found a few solutions which has a significantly smaller emittance than present value. They may be useful for some special low emittance operation modes dedicated to developments on new light sources technologies and their applications.  
poster icon Poster THPAB089 [1.592 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB089  
About • paper received ※ 19 May 2021       paper accepted ※ 27 July 2021       issue date ※ 16 August 2021  
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THPAB090 Progress with the Diamond-II Storage Ring Lattice storage-ring, emittance, sextupole, injection 3973
 
  • H. Ghasem, I.P.S. Martin, B. Singh
    DLS, Oxfordshire, United Kingdom
  
  Building on the CDR proposal for the Diamond-II storage ring, a number of changes have been implemented to improve the performance of the lattice. Firstly, anti-bend magnets have been utilized to provide additional control over the dispersion function, and an improved symmetrization in the phase advance between the sextupoles was found to be beneficial for the dynamic aperture. Furthermore, the longitudinal variable bends have been tailored to reduce the emittance and have had transverse gradient added to improve the optics control in the mid-straights. In the absence of IDs, the current design provides 161 pm electron beam emittance, reducing to 139 pm once all effects are taken into account. The dynamic aperture is large enough to support an off-axis injection scheme using a nonlinear kicker and has a lifetime greater than 4 h. In this paper, the main parameters and magnet specifications for the Diamond-II lattice are provided. The related linear and non-linear beam dynamics issues are discussed, along with the impact of IDs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB090  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 26 August 2021  
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THPAB104 Magnetic Error Effects of the Storage Ring for the Southern Advanced Photon Source closed-orbit, alignment, quadrupole, optics 3980
 
  • J. Chen, Y. Jiao, X. Liu, S. Wang
    IHEP, Beijing, People’s Republic of China
  • Y. Zhao
    IHEP CSNS, Guangdong Province, People’s Republic of China
  
  There are various magnetic errors in the actual accelerator, which will significantly affect the beam quality and machine performance. The diffraction-limited storage ring (DLSR) of Southern Advanced Photon Source (SAPS) will use a large number of ultra-high gradient quadrupoles and sextupoles, which, in turn, leads to the tight tolerance of beam parameters to magnetic errors. Based on a preliminary designed storage ring lattice of the SAPS, the influence of various magnetic errors on lattice parameters has been evaluated.  
poster icon Poster THPAB104 [0.588 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB104  
About • paper received ※ 17 May 2021       paper accepted ※ 23 June 2021       issue date ※ 18 August 2021  
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THPAB124 Application of the FFA Concept to a Muon Collider Complex quadrupole, collider, optics, focusing 4006
 
  • S. Machida, J.-B. Lagrange
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • M.E. Topp-Mugglestone
    JAI, Oxford, United Kingdom
  
  Muon collider complex is one of the places where the concept of fixed field alternating gradient (FFA) optics can be applied with great benefits. Vertical excursion FFA (vFFA) provides the isochronous condition for the ultra-relativistic muon beams after pre-acceleration. Together with the fixed transverse tune, it will be an ideal accelerator of short-lived muon beams with no time variation of magnetic fields and RF frequency. Novel collider ring optics is a design based on skew quadrupole after extracting essential functions from vFFA. That enables control of the momentum compaction factor. Neutrinos from the continuing decay of muons are spread out with orbit wiggling in the vertical direction as well as horizontal. The paper discusses the underline principle and describes some design examples.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB124  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 28 August 2021  
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THPAB190 Optimising and Extending a Single-Particle Tracking Library for High Parallel Performance GPU, simulation, interface, hardware 4146
 
  • M. Schwinzerl, H. Bartosik, R. De Maria, G. Iadarola, K. Paraschou
    CERN, Geneva, Switzerland
  • A. Oeftiger
    GSI, Darmstadt, Germany
  • M. Schwinzerl
    KFUG/IMSC, Graz, Austria
  
  SixTrackLib is a library for performing beam-dynamics simulations on highly parallel computing devices such as shared memory multi-core processors or graphical processing units (GPUs). Its single-particle approach fits very well with parallel implementations with reasonable baseline performance, making such a library an interesting building block for various use cases, including simulations covering collective effects. We describe optimizations to improve their performance on SixTrackLib’s main target platforms and the associated performance gains. Finally, we outline the implemented technical interfaces and extensions that allow SixTrackLib to be used in a wider range of applications and studies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB190  
About • paper received ※ 18 May 2021       paper accepted ※ 14 July 2021       issue date ※ 16 August 2021  
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THPAB191 Physics-Enhanced Reinforcement Learning for Optimal Control network, controls, simulation, alignment 4150
 
  • A.N. Ivanov, I.V. Agapov, A. Eichler, S. Tomin
    DESY, Hamburg, Germany
  
  We propose an approach for incorporating accelerator physics models into reinforcement learning agents. The proposed approach is based on the Taylor mapping technique for simulation of the particle dynamics. The resulting computational graph is represented as a polynomial neural network and embedded into the traditional reinforcement learning agents. The application of the model is demonstrated in a nonlinear simulation model of beam transmission. The comparison of the approach with the traditional numerical optimization as well as neural networks based agents demonstrates better convergence of the proposed technique.  
poster icon Poster THPAB191 [0.846 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB191  
About • paper received ※ 11 May 2021       paper accepted ※ 29 July 2021       issue date ※ 24 August 2021  
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THPAB197 Enhancing Efficiency of Multi-Objective Neural-Network-Assisted Nonlinear Dynamics Lattice Optimization via 1-D Aperture Objectives & Objective Focusing focusing, network, simulation, storage-ring 4156
 
  • Y. Hidaka, D.A. Hidas, F. Plassard, T.V. Shaftan, G.M. Wang
    BNL, Upton, New York, USA
  
  Funding: This work is supported by U.S. DOE under Contract No. DE-SC0012704.
Mutli-objective optimizers such as multi-objective genetic algorithm (MOGA) have been quite popular in discovering desirable lattice solutions for accelerators. However, even these successful algorithms can become ineffective as the dimension and range of the search space increase due to exponential growth in the amount of exploration required to find global optima. This difficulty is even more exacerbated by the resource-intensive and time-consuming tendency for the evaluations of nonlinear beam dynamics. Lately the use of surrogate models based on neural network has been drawing attention to alleviate this problem. Following this trend, to further enhance the efficiency of nonlinear lattice optimization for storage rings, we propose to replace typically used objectives with those that are less time-consuming and to focus on a single objective constructed from multiple objectives, which can maximize utilization of the trained models through local optimization and objective gradient extraction. We demonstrate these enhancements using a NSLS-II upgrade lattice candidate as an example. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB197  
About • paper received ※ 20 May 2021       paper accepted ※ 23 June 2021       issue date ※ 10 August 2021  
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THPAB221 Multi-Objective Optimization with ACE3P and IMPACT cathode, cavity, simulation, interface 4223
 
  • D.A. Bizzozero, J. Qiang
    LBNL, Berkeley, California, USA
  • L. Ge, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  
  Funding: This work is supported by the Director of the Office of Science of the US Department of Energy under contracts DE-AC02-05-CH11231 and DE-AC02-76-SF00515.
Photo injector design is an important consideration in the construction of next-generation accelerators. In current injector optimization, components (e.g. RF cavities) are individually shape-optimized for performance subject to requirements such as peak surface field, shunt impedance, and resonant frequency. Once these component shapes are determined, beam dynamics simulations optimize the injector lattice by adjusting parameters such as the amplitude and phase of the driving fields. However, this form of beam dynamics optimization is restricted by the fixed geometry and field profile of the components. To optimize accelerator design more generally, a coupled optimization of the cavity shape and beam parameters is required. For this coupled optimization problem, we have created an integrated ACE3P-IMPACT workflow. Within this workflow, component geometries are adjusted, field modes are computed with Omega3P (a module in the ACE3P suite), and beam dynamics are simulated with IMPACT-T. This workflow is encapsulated into a multi-objective optimization algorithm using the DEAP* and libEnsemble** Python libraries to yield a Pareto-optimal set of solutions for a simple injector model.
* F.-A. Fortin et al, DEAP: Evolutionary Algorithms Made Easy, J Mach Learn Res, 13, 2171-2175, July 2012
** S. Hudson et al, libEnsemble User Manual, Argonne National Laboratory, Rev 0.7.1, 2020 		 
poster icon Poster THPAB221 [1.842 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB221  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 14 August 2021  
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THPAB236 First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator focusing, closed-orbit, optics, simulation 4262
 
  • M.E. Topp-Mugglestone, S.L. Sheehy
    JAI, Oxford, United Kingdom
  • J.-B. Lagrange, S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236  
About • paper received ※ 13 May 2021       paper accepted ※ 14 July 2021       issue date ※ 10 August 2021  
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THPAB240 Combined Effect of IBS and Impedance on the Longitudinal Beam Dynamics emittance, experiment, simulation, wakefield 4274
 
  • A. Blednykh
    Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
  • B. Bacha, G. Bassi, T.V. Shaftan, V.V. Smaluk
    BNL, Upton, New York, USA
  • M. Borland, R.R. Lindberg
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The horizontal/vertical emittances, the bunch length, and the energy spread increase have been studied in the NSLS-II as a function of a single bunch current. The monotonic growth of the horizontal emittance dependence and the energy spread dependence on the single bunch current below the microwave instability threshold can be explained by the Intrabeam Scattering Effect (IBS). The IBS effect results in an increase in the bunch length and the microwave instability thresholds. It was observed experimentally by varying the vertical emittance. To compare with experimental data, particle tracking simulations have been performed with the ELEGANT code including both IBS and the total longitudinal wakefield calculated from the 3D electromagnetic code GdfidL. The same particle tracking simulations have also been applied for the APS-U project, where IBS is predicted to produce only a marginal effect. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB240  
About • paper received ※ 20 May 2021       paper accepted ※ 05 July 2021       issue date ※ 14 August 2021  
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