IPAC2021 - List of Keywords (closed-orbit)

Paper	Title	Other Keywords	Page
MOPAB039	Amplitude-Dependent Shift of Betatron Tunes and Its Relation to Long-Term Circumference Variations at NSLS-II	lattice, sextupole, simulation, 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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MOPAB119	Comparisons Between AT and Elegant Tracking	lattice, 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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MOPAB198	Study on Magnet Sorting of the CSNS/RCS Dipoles	dipole, MMI, neutron, controls	665
	Y. Li, Y.W. An IHEP, Beijing, People’s Republic of China Z.P. Li, S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The 1.6GeV rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high-power pulsed proton machine aiming for 500kW output beam power. Now, the routine output beam power has been increased to 100kW. However, the horizontal bare orbit in the ring is large (15mm) and the number of correctors is small, which brings great challenges to the ramp-up of beam power. It is found that the bare orbit in AC mode is 3-4mm larger than that in DC mode. The reason is that the AC dipoles field error is larger than DC dipoles field error. Therefore, it is proposed to sort dipoles again according to the AC dipoles field error. In order to reduce the risk of beam commissioning, fewer magnets should to be moved to achieve smaller orbit. The best results of moving two to six magnets were calculated. After sorting, the orbit can be reduced by 3-4mm, which reduces the difficulty of orbit correction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB198
About •	paper received ※ 16 May 2021 paper accepted ※ 21 May 2021 issue date ※ 14 August 2021
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MOPAB226	Analytical Description of the Steerer Parameters in the Bilinear-Exponential Model at DELTA	betatron, storage-ring, coupling, simulation	737
	S. Kötter DELTA, Dortmund, Germany
	At DELTA, a 1.5 GeV synchrotron radiation source operated by the TU Dortmund University, an analytical description of the steerer parameters in the bilinear-exponential (BE) model has been developed. The BE model describes the coupled orbit response in a storage ring. It is used in the closed-orbit bilinear-exponential analysis (COBEA) algorithm to decompose orbit response matrices into beta function, betatron phase, and a scaled dispersion. After introducing the BE model and the analytical steerer parameters, a simulation-based comparison of the BE model and another coupled orbit response model is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB226
About •	paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 11 August 2021
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MOPAB228	Introducing two Energy-Correction Schemes at DELTA	storage-ring, operation, simulation, injection	740
	S. Kötter DELTA, Dortmund, Germany
	At DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University, two methods to correct the beam energy of the storage ring have been tested. The first one is capable of maintaining the current beam energy. The second method is used to find the optimal orbit length. Here, the ideas behind both methods are explained and first test results are presented. Numerical studies are shown together with measurement results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB228
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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MOPAB234	Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields	dipole, focusing, simulation, optics	760
	K. Hwang, C.E. Mitchell, R.D. Ryne LBNL, Berkeley, California, USA
	Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231 There have been questions regarding the impact of the dipole fringe-field models (used by accelerator codes including ELEGANT and MADX) on vertical chromaticity. Here, we analyze the cause of the disagreement among codes and suggest a correction.
	Poster MOPAB234 [0.486 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB234
About •	paper received ※ 20 May 2021 paper accepted ※ 01 June 2021 issue date ※ 23 August 2021
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TUPAB009	SuperKEKB Optics Measurements Using Turn-by-Turn Beam Position Data	optics, damping, collider, positron	1352
	J. Keintzel, R. Tomás García CERN, Geneva, Switzerland H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, M. Tobiyama, R.J. Yang KEK, Ibaraki, Japan
	SuperKEKB, an asymmetric electron-positron collider, has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} using crab-waist collision scheme. In order to reach the design value of 6×10³⁵ \si{cm^-2s^-1} a vertical beta function at the interaction point of §I{0.3}{mm} is required, demanding unprecedented optics control. Turn-by-turn beam position data could enable fast optics measurements for rapid identification of unexpected error sources. Experiments exploring various data acquisition techniques at different squeezing steps during commissioning are presented and compared to results obtained from closed orbit distortion.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB009
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021
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TUPAB042	Large Radial Shifts in the EIC Hadron Storage Ring	dipole, hadron, electron, insertion	1443
	S. Peggs, J.S. Berg, K.A. Drees, X. Gu, C. Liu, H. Lovelace III, Y. Luo, G.J. Marr, A. Marusic, F. Méot, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, M. Valette, S. Verdú-Andrés BNL, Upton, New York, USA K.E. Deitrick Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA B.R. Gamage JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The Electron Ion Collider will collide hadrons in the Hadron Storage Ring (HSR) with ultra-relativistic electrons in the Electron Storage Ring. The HSR design trajectory includes a large radial shift over a large fraction of its circumference, in order to adjust the hadron path length to synchronize collisions over a broad range of hadron energies. The design trajectory goes on-axis through the magnets, crab cavities and other components in the six HSR Insertion Regions. This paper discusses the issues involved and reports on past and future beam experiments in the Relativistic Heavy Ion Collider, which will be upgraded to become the HSR.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB042
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021
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TUPAB048	HMBA Optics Correction Experience at ESRF	optics, lattice, MMI, 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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TUPAB208	FETS-FFA Ring Study	lattice, injection, optics, 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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TUPAB214	Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis	operation, synchrotron, storage-ring, lattice	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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WEPAB127	Accurate Measurements of Undulator Particle Beam Entrance/Exit Angles Using Improved Hall Probes and Calibration Process	undulator, photon, insertion, insertion-device	2907
	I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu ANL, Lemont, Illinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357. The Advanced Photon Source Upgrade (APS-U) undulator requirements were changed from the first and second field integrals to the entrance and exit angles of the particle beam. This provides the user with the best radiation view angle by the storage ring closed orbit correction system. To satisfy such requirements we use improved Senis Hall probes and calibration process. In addition to the normal NMR calibration of the sensors, the calibration was further refined using stretch-coil integrals to make accurate measurements.
	Poster WEPAB127 [0.620 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB127
About •	paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 19 August 2021
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WEPAB216	6D Simulations of PIP-II Booster Injection	injection, scattering, controls, booster	3138
	J.-F. Ostiguy, D.E. Johnson Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The PIP-II superconducting linac will deliver 2 mA average H^- beam current at 800 MeV to the existing Booster synchrotron over a period of 0.55 ms (285 turns). As a result, the injected beam power will quadruple to 17 kW. Safe operation at the increased beam power implies careful attention to the origin, magnitude, and distribution of both controlled and uncontrolled losses. Uncontrolled losses are due to neutral ions in excited states stripped in downstream magnets and large angle scattered protons from parasitic foil hits. The relative magnitudes of these loss mechanisms is used to determine the optimal foil thickness. A transverse painting scheme involving closed orbit motion will be used to mitigate space charge effects and minimize parasitic foil hits. Using a detailed full 6D simulation of the injection process, we compute large angle scattering losses and compare results to back of the envelope estimates. We investigate possible impact of space charge on the emittance and beam distribution both during and at the conclusion of the injection period.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB216
About •	paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 10 August 2021
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WEPAB280	Two-Dimensional Beam-Beam Invariant with Applications to HL-LHC	optics, resonance, lattice, luminosity	3301
	D. Kaltchev TRIUMF, Vancouver, Canada
	Long-range beam-beam interactions represent the most severe limitation on the performance and achievable luminosity of circular collider. The paper presents a two-dimensional nonlinear Courant Snyder Invariant derived to first order in the beam-beam perturbation and based on the two-dimensional coefficients in the Fourier expansion of the Beam-beam Hamiltonian. Its validity in case of HL-LHC lattices with realistic beam-beam setup is verified with MadX tracking.
	Poster 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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THPAB104	Magnetic Error Effects of the Storage Ring for the Southern Advanced Photon Source	lattice, 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 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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THPAB232	Study of Nonlinear Properties of ESR via Tune Scans	quadrupole, optics, storage-ring, controls	4250
	G. Franchetti GSI, Darmstadt, Germany
	The ESR storage ring at GSI is a key accelerator for the FAIR phase zero. This phase requires several highly specialized beam manipulations, which range from beam storage to deceleration of several ion species with the ultimate goal to provide intense highly charge ions to CRYRING. This plan will bring the ESR storage ring into a unique unexplored regime of accelerator operations where nonlinear dynamics, IBS, cooling, and high intensity will all become strongly interdependent. It is, therefore, necessary to acquire the best knowledge of the machine starting from its nonlinear dynamics properties. In this work, we present the development of a strategy to be used in the ESR, in which tune scans are used to explore the nonlinear properties of the accelerator. This approach is discussed with the help of simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB232
About •	paper received ※ 13 May 2021 paper accepted ※ 13 July 2021 issue date ※ 25 August 2021
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THPAB236	First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator	lattice, focusing, 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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THPAB264	FOFB System Upgrade to ZynqMP FPGA with Fast ORM Measurement	FPGA, storage-ring, hardware, EPICS	4322
	Y.E. Tan, S. Chen, R.B. Hogan, A. Michalczyk AS - ANSTO, Clayton, Australia
	The FOFB processor has been ported from a Vertex 6 FPGA to a ZynqMP SoC (System on Chip) to provide additional resources to include the enhanced orbit diagnostics (EOD) system that has been designed to inject sinusoidal and pink noise through the feedback loop. The amplitude, duration, phase and frequency of sinusoidal, amplitude and duration of pink noise is user programmable.
	Poster THPAB264 [1.601 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB264
About •	paper received ※ 04 June 2021 paper accepted ※ 26 July 2021 issue date ※ 15 August 2021
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Paper

Title

Other Keywords

Page

MOPAB039

Amplitude-Dependent Shift of Betatron Tunes and Its Relation to Long-Term Circumference Variations at NSLS-II

lattice, sextupole, simulation, 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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MOPAB119

Comparisons Between AT and Elegant Tracking

lattice, 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

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paper received ※ 20 May 2021 paper accepted ※ 31 May 2021 issue date ※ 30 August 2021

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MOPAB198

Study on Magnet Sorting of the CSNS/RCS Dipoles

dipole, MMI, neutron, controls

665

Y. Li, Y.W. An
IHEP, Beijing, People’s Republic of China
Z.P. Li, S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The 1.6GeV rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high-power pulsed proton machine aiming for 500kW output beam power. Now, the routine output beam power has been increased to 100kW. However, the horizontal bare orbit in the ring is large (15mm) and the number of correctors is small, which brings great challenges to the ramp-up of beam power. It is found that the bare orbit in AC mode is 3-4mm larger than that in DC mode. The reason is that the AC dipoles field error is larger than DC dipoles field error. Therefore, it is proposed to sort dipoles again according to the AC dipoles field error. In order to reduce the risk of beam commissioning, fewer magnets should to be moved to achieve smaller orbit. The best results of moving two to six magnets were calculated. After sorting, the orbit can be reduced by 3-4mm, which reduces the difficulty of orbit correction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB198

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paper received ※ 16 May 2021 paper accepted ※ 21 May 2021 issue date ※ 14 August 2021

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MOPAB226

Analytical Description of the Steerer Parameters in the Bilinear-Exponential Model at DELTA

betatron, storage-ring, coupling, simulation

737

S. Kötter
DELTA, Dortmund, Germany

At DELTA, a 1.5 GeV synchrotron radiation source operated by the TU Dortmund University, an analytical description of the steerer parameters in the bilinear-exponential (BE) model has been developed. The BE model describes the coupled orbit response in a storage ring. It is used in the closed-orbit bilinear-exponential analysis (COBEA) algorithm to decompose orbit response matrices into beta function, betatron phase, and a scaled dispersion. After introducing the BE model and the analytical steerer parameters, a simulation-based comparison of the BE model and another coupled orbit response model is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB226

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paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 11 August 2021

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MOPAB228

Introducing two Energy-Correction Schemes at DELTA

storage-ring, operation, simulation, injection

740

S. Kötter
DELTA, Dortmund, Germany

At DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University, two methods to correct the beam energy of the storage ring have been tested. The first one is capable of maintaining the current beam energy. The second method is used to find the optimal orbit length. Here, the ideas behind both methods are explained and first test results are presented. Numerical studies are shown together with measurement results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB228

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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MOPAB234

Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields

dipole, focusing, simulation, optics

760

K. Hwang, C.E. Mitchell, R.D. Ryne
LBNL, Berkeley, California, USA

Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
There have been questions regarding the impact of the dipole fringe-field models (used by accelerator codes including ELEGANT and MADX) on vertical chromaticity. Here, we analyze the cause of the disagreement among codes and suggest a correction.

Poster MOPAB234 [0.486 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB234

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paper received ※ 20 May 2021 paper accepted ※ 01 June 2021 issue date ※ 23 August 2021

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TUPAB009

SuperKEKB Optics Measurements Using Turn-by-Turn Beam Position Data

optics, damping, collider, positron

1352

J. Keintzel, R. Tomás García
CERN, Geneva, Switzerland
H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, M. Tobiyama, R.J. Yang
KEK, Ibaraki, Japan

SuperKEKB, an asymmetric electron-positron collider, has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} using crab-waist collision scheme. In order to reach the design value of 6×10³⁵ \si{cm^-2s^-1} a vertical beta function at the interaction point of §I{0.3}{mm} is required, demanding unprecedented optics control. Turn-by-turn beam position data could enable fast optics measurements for rapid identification of unexpected error sources. Experiments exploring various data acquisition techniques at different squeezing steps during commissioning are presented and compared to results obtained from closed orbit distortion.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB009

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 24 August 2021

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TUPAB042

Large Radial Shifts in the EIC Hadron Storage Ring

dipole, hadron, electron, insertion

1443

S. Peggs, J.S. Berg, K.A. Drees, X. Gu, C. Liu, H. Lovelace III, Y. Luo, G.J. Marr, A. Marusic, F. Méot, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, M. Valette, S. Verdú-Andrés
BNL, Upton, New York, USA
K.E. Deitrick
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
B.R. Gamage
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Electron Ion Collider will collide hadrons in the Hadron Storage Ring (HSR) with ultra-relativistic electrons in the Electron Storage Ring. The HSR design trajectory includes a large radial shift over a large fraction of its circumference, in order to adjust the hadron path length to synchronize collisions over a broad range of hadron energies. The design trajectory goes on-axis through the magnets, crab cavities and other components in the six HSR Insertion Regions. This paper discusses the issues involved and reports on past and future beam experiments in the Relativistic Heavy Ion Collider, which will be upgraded to become the HSR.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB042

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 21 August 2021

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TUPAB048

HMBA Optics Correction Experience at ESRF

optics, lattice, MMI, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB048

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paper received ※ 10 May 2021 paper accepted ※ 11 June 2021 issue date ※ 20 August 2021

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TUPAB208

FETS-FFA Ring Study

lattice, injection, optics, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB208

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paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 14 August 2021

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TUPAB214

Alpha Buckets in Longitudinal Phase Space: A Bifurcation Analysis

operation, synchrotron, storage-ring, lattice

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB214

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paper received ※ 12 May 2021 paper accepted ※ 17 June 2021 issue date ※ 26 August 2021

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WEPAB127

Accurate Measurements of Undulator Particle Beam Entrance/Exit Angles Using Improved Hall Probes and Calibration Process

undulator, photon, insertion, insertion-device

2907

I. Vasserman, R.J. Dejus, Y. Piao, M.F. Qian, J.Z. Xu
ANL, Lemont, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
The Advanced Photon Source Upgrade (APS-U) undulator requirements were changed from the first and second field integrals to the entrance and exit angles of the particle beam. This provides the user with the best radiation view angle by the storage ring closed orbit correction system. To satisfy such requirements we use improved Senis Hall probes and calibration process. In addition to the normal NMR calibration of the sensors, the calibration was further refined using stretch-coil integrals to make accurate measurements.

Poster WEPAB127 [0.620 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB127

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paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 19 August 2021

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WEPAB216

6D Simulations of PIP-II Booster Injection

injection, scattering, controls, booster

3138

J.-F. Ostiguy, D.E. Johnson
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The PIP-II superconducting linac will deliver 2 mA average H^- beam current at 800 MeV to the existing Booster synchrotron over a period of 0.55 ms (285 turns). As a result, the injected beam power will quadruple to 17 kW. Safe operation at the increased beam power implies careful attention to the origin, magnitude, and distribution of both controlled and uncontrolled losses. Uncontrolled losses are due to neutral ions in excited states stripped in downstream magnets and large angle scattered protons from parasitic foil hits. The relative magnitudes of these loss mechanisms is used to determine the optimal foil thickness. A transverse painting scheme involving closed orbit motion will be used to mitigate space charge effects and minimize parasitic foil hits. Using a detailed full 6D simulation of the injection process, we compute large angle scattering losses and compare results to back of the envelope estimates. We investigate possible impact of space charge on the emittance and beam distribution both during and at the conclusion of the injection period.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB216

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paper received ※ 20 May 2021 paper accepted ※ 24 June 2021 issue date ※ 10 August 2021

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WEPAB280

Two-Dimensional Beam-Beam Invariant with Applications to HL-LHC

optics, resonance, lattice, luminosity

3301

D. Kaltchev
TRIUMF, Vancouver, Canada

Long-range beam-beam interactions represent the most severe limitation on the performance and achievable luminosity of circular collider. The paper presents a two-dimensional nonlinear Courant Snyder Invariant derived to first order in the beam-beam perturbation and based on the two-dimensional coefficients in the Fourier expansion of the Beam-beam Hamiltonian. Its validity in case of HL-LHC lattices with realistic beam-beam setup is verified with MadX tracking.

Poster WEPAB280 [1.235 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB280

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paper received ※ 14 May 2021 paper accepted ※ 06 July 2021 issue date ※ 12 August 2021

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THPAB104

Magnetic Error Effects of the Storage Ring for the Southern Advanced Photon Source

lattice, 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 THPAB104 [0.588 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB104

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paper received ※ 17 May 2021 paper accepted ※ 23 June 2021 issue date ※ 18 August 2021

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THPAB232

Study of Nonlinear Properties of ESR via Tune Scans

quadrupole, optics, storage-ring, controls

4250

G. Franchetti
GSI, Darmstadt, Germany

The ESR storage ring at GSI is a key accelerator for the FAIR phase zero. This phase requires several highly specialized beam manipulations, which range from beam storage to deceleration of several ion species with the ultimate goal to provide intense highly charge ions to CRYRING. This plan will bring the ESR storage ring into a unique unexplored regime of accelerator operations where nonlinear dynamics, IBS, cooling, and high intensity will all become strongly interdependent. It is, therefore, necessary to acquire the best knowledge of the machine starting from its nonlinear dynamics properties. In this work, we present the development of a strategy to be used in the ESR, in which tune scans are used to explore the nonlinear properties of the accelerator. This approach is discussed with the help of simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB232

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paper received ※ 13 May 2021 paper accepted ※ 13 July 2021 issue date ※ 25 August 2021

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THPAB236

First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator

lattice, focusing, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236

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paper received ※ 13 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021

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THPAB264

FOFB System Upgrade to ZynqMP FPGA with Fast ORM Measurement

FPGA, storage-ring, hardware, EPICS

4322

Y.E. Tan, S. Chen, R.B. Hogan, A. Michalczyk
AS - ANSTO, Clayton, Australia

The FOFB processor has been ported from a Vertex 6 FPGA to a ZynqMP SoC (System on Chip) to provide additional resources to include the enhanced orbit diagnostics (EOD) system that has been designed to inject sinusoidal and pink noise through the feedback loop. The amplitude, duration, phase and frequency of sinusoidal, amplitude and duration of pink noise is user programmable.

Poster THPAB264 [1.601 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB264

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paper received ※ 04 June 2021 paper accepted ※ 26 July 2021 issue date ※ 15 August 2021

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