IPAC2021 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOXB02	First Results of the IOTA Ring Research at Fermilab	experiment, electron, lattice, 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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MOPAB006	Optics Configurations for Improved Machine Impedance and Cleaning Performance of a Multi-Stage Collimation Insertion	collimation, impedance, collider, scattering	57
	R. Bruce, R. De Maria, M. Giovannozzi, N. Mounet, S. Redaelli CERN, Geneva, Switzerland
	For a two-stage collimation system, the betatron phase advance between the primary and secondary stages is usually set to maximise the absorption of secondary particles outscattered from the primary. Another constraint is the contribution to the ring impedance of the collimation system, which can be decreased through an optimized insertion optics, featuring large values of the beta functions. In this article we report on first studies of such an optics for the CERN LHC. In addition to a gain in impedance, we show that the cleaning efficiency can be improved thanks to the large beta functions, even though the phase advance is not set at the theoretical optimum.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB006
About •	paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 11 August 2021
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MOPAB007	Prospect for Interaction Region Local Coupling Correction in the LHC Run 3	coupling, quadrupole, luminosity, MMI	61
	F. Soubelet, T.H.B. Persson, R. Tomás García CERN, Geneva, Switzerland O. Apsimon, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom O. Apsimon, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was supported by STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) and CERN. Successful operation of large scale particle accelerators depends on the precise correction of unavoidable magnet field or alignment errors present in the machine. In the LHC Run 2, local linear coupling in the Interaction Regions (IR) has been proven to have a severe impact on beam size and hence the luminosity - up to a 50% decrease -, making its handling a target for Run 3 and High Luminosity LHC (HL-LHC). However, current measurement methods are not optimised for local IR coupling. In this contribution, an approach to accurately minimise IR local coupling based on correlated external variables such as the \|C-\| is proposed. The validity of the method is demonstrated through simulations and benchmarked against theoretical values, such as Resonance Driving Terms (RDTs) and Ripken parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB007
About •	paper received ※ 17 May 2021 paper accepted ※ 23 July 2021 issue date ※ 19 August 2021
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MOPAB012	Energy Deposition Study of the CERN HL-LHC Optics v1.5 in the ATLAS and CMS Insertions	luminosity, insertion, proton, radiation	76
	M. Sabaté-Gilarte, F. Cerutti CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project The High Luminosity Large Hadron Collider (HL-LHC) is the approved CERN project aiming at further increasing the integrated luminosity of the LHC by a factor 10. As such, it implies a complete redesign of the experimental high-luminosity insertions of ATLAS and CMS. The progressive evolution of the new layout and optics requires a continuous analysis of the radiation environment, to which magnets and other equipment are exposed to. This is assured by means of Monte Carlo simulations of the collision debris on the evolving machine model. The latter featured several developments, such as the explicit inclusion of the cold protection diodes of the final focusing circuits as well as the crab cavities cryomodule. This work presents the most updated characterization of the radiation field with FLUKA and its impact in the insertion region and the dispersion suppressor of Point 1 and 5, for the HL-LHC optics v1.5 released in 2019. Various optimization and mitigation studies are highlighted, providing key information for maximizing the lifetime of new and present magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB012
About •	paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 21 August 2021
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MOPAB021	A Dispersive Quadrupole Scan Technique for Transverse Beam Characterization	quadrupole, SRF, emittance, booster	107
	J. Kallestrup, M. Aiba PSI, Villigen PSI, Switzerland N. Carmignani, T.P. Perron ESRF, Grenoble, France
	Quadrupole scans are one of the standard techniques to characterize the transverse beam properties in transfer lines or linacs. However, in the presence of dispersion the usage of regular quadrupole scans will lead to erroneous estimates of the beam parameters. The standard solution to this problem is to measure the dispersion and then subtract it in the post-analysis of the quadrupole scan measurements assuming the design energy spread. Here we show that the dispersive contribution to the beam size can be included in the quadrupole scan procedure, forming a linear system of equations that can be solved to obtain both the betatronic and dispersive beam parameters. The method is tested at both the SLS and ESRF booster-to-ring transfer lines leading to reasonable estimates of the beam parameters.
	Poster MOPAB021 [0.447 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB021
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 19 August 2021
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MOPAB022	FailSim: A Numerical Toolbox for the Study of Fast Failures and Their Impact on Machine Protection at the CERN Large Hadron Collider	simulation, beam-losses, quadrupole, machine-protect	111
	C. Hernalsteens, G. Sterbini, O.K. Tuormaa, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	The High Luminosity LHC (HL-LHC) foresees to reach a nominal, levelled luminosity of 5·10³⁴ cm^-2 s⁻¹ through a higher beam brightness and by using new equipment, such as larger aperture final focusing quadrupole magnets. The HL-LHC upgrade has critical impacts on the machine protection strategy, as the stored beam energy reaches 700 MJ for each of the two beams. Some failure modes of the novel active superconducting magnet protection system of the inner triplet magnets, namely the Coupling-Loss Induced Quench (CLIQ) systems, have been identified as critical. This paper reports on FailSim, a Python-language framework developed to study the machine protection impact of failure cases and their proposed mitigation. It provides seamless integration of the successive phases required by the simulation studies, i.e., verifying the optics, preparing and running a MAD-X instance for multiple particle tracking, processing and analysing the simulation results and summarising them with the relevant plots to provide a solid estimate of the beam losses, their location and time evolution. The paper also presents and discusses the result of its application on the spurious discharge of a CLIQ unit.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB022
About •	paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 18 August 2021
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MOPAB036	Different Operation Regimes at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)	operation, lattice, 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 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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MOPAB037	On Possibility of Alpha-buckets Detecting at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)	storage-ring, operation, synchrotron, electron	167
	A.I. Papash, T. Boltz, M. Brosi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	Computer studies of longitudinal motion have been performed with the objective to estimate the possibility of detection of alpha-buckets at the KIT storage ring KARA (Karlsruhe Research Accelerator). The longitudinal equations of motion and the Hamiltonian were expanded to high order terms of the energy deviation of particles in a beam. Roots of third order equation for three leading terms of momentum compaction factor and free energy independent term were derived in a form suitable for analytical estimations. Averaged quadratic terms of closed orbit distortions caused by misalignment of magnetic elements in a ring lead to orbit lengthening independent of particle energy deviation. Particle transverse excursions were estimated and are taken into account. Simulations have been bench-marked on existing experiments at Metrology Light Source (MLS) in Berlin (Germany) and SOLEIL (France). Parameters of three simultaneous beams and alpha buckets at MLS and SOLEIL have been reproduced with high accuracy. A computer model of KARA was used to predict behavior and the dynamics of possible simultaneous beams in the ring.
	Poster MOPAB037 [1.269 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB037
About •	paper received ※ 11 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021
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MOPAB047	A CAD Tool for Linear Optics Design: A Use Case Approach	controls, software, MMI, GUI	205
	J. Bengtsson HZB, Berlin, Germany T.J.R. Nicholls, W.A.H. Rogers DLS, Oxfordshire, United Kingdom
	The formula relevant for linear optics design of synchrotrons are derived systematically from first principles, i.e., an exercise in Hamiltonian dynamics. Equipped with these, the relevant use cases are then captured; for a streamlined approach. To enable professionals, i.e., software engineers, to efficiently prototype & architect a CAD tool available to mechanical engineers since the mid-1960s. In other words, robust design of a modern synchrotron is an exercise in/pursuit of the art of Engineering-Science.
	Poster MOPAB047 [1.059 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB047
About •	paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 15 August 2021
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MOPAB048	Robust Design and Control of the Nonlinear Dynamics for BESSY-III	lattice, controls, 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 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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MOPAB063	Commissioning Strategy for Diamond-II	MMI, lattice, 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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MOPAB115	ATS/STA Transfer Line Design for the ALS Upgrade Project (ALS-U)	injection, storage-ring, kicker, extraction	417
	C. Sun, M.P. Ehrlichman, T. Hellert, M. Juchno, J.-Y. Jung, M. Mardenfeld, J.R. Osborn, G. Penn, C. Steier, C.A. Swenson, M. Venturini LBNL, Berkeley, California, USA
	At the Advanced Light Source Upgrade (ALS-U), an on-axis swap-out injection will be used to replenish depleted bunches in the storage ring with refreshed bunches from the full energy accumulator ring. To implement this scheme, two transfer lines are required between the storage ring and the accumulator ring: the accumulator-to-storage-ring (ATS) transfer line and the storage-ring-to-accumulator (STA) transfer line. The design of the ATS/STA transfer lines is a challenging task as they must fit within a tight injection region while also accommodating the storage and accumulator rings at different elevations. Moreover, the ATS/STA design needs to meet both the boundary conditions and optics requirements. In this paper, we will present a design option for these ATS/STA transfer lines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB115
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 15 August 2021
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MOPAB184	Unsupervised Learning Techniques for Tune Cleaning Measurement	ISOL, coupling, luminosity, quadrupole	624
	H. Garcia Morales Oxford University, Physics Department, Oxford, Oxon, United Kingdom E. Fol, R. Tomás García CERN, Meyrin, Switzerland
	Precise measurements of tune and its stability are crucial for various optics analyses in the LHC, e.g. for the determination of the beta star using K-modulation. LHC BBQ system provides tune measurements online and stores the tune data. We apply unsupervised machine learning techniques on BBQ tune data in order to provide an automatic outlier detection method for better measurements of tune shifts and unexpected tune jitters.
	Poster MOPAB184 [0.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB184
About •	paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021
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MOPAB185	HL-LHC Local Linear Optics Correction at the Interaction Regions	quadrupole, interaction-region, simulation, lattice	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 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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MOPAB186	Comparison of Segment-by-Segment and Action-Phase-Jump Techniques in the Calculation of IR Local Corrections in LHC	quadrupole, simulation, interaction-region, MMI	632
	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
	The correction of the local optics at the Interaction Regions of the LHC is crucial to ensure a good performance of the machine. In this paper, we compare two different techniques for local optics correction: Action-Phase Jump and Segment-by-Segment techniques. The comparison is made in view of future machine configurations such as Run 3 LHC optics and HL-LHC optics.
	Poster MOPAB186 [0.349 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB186
About •	paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021
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MOPAB213	Characterization of Linear Optics and Beam Parameters for the APS Booster with Turn-by-Turn BPM Data	booster, betatron, synchrotron, kicker	703
	X. Huang, H. Shang, C. Yao ANL, Lemont, Illinois, USA
	We take turn-by-turn (TBT) BPM data on the energy ramp of the APS Booster, and analyze the data with the independent component analysis. The extraction kicker was used to excite the betatron motion. The linear optics of the machine is characterized with the TBT BPM data. We also analyze the decoherence pattern of the kicked beam, from which we are able to derive beam distribution parameters, such as the momentum spread.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB213
About •	paper received ※ 13 May 2021 paper accepted ※ 11 June 2021 issue date ※ 19 August 2021
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MOPAB214	Linear Optics Measurement for the APS Ring with Turn-by-Turn BPM Data	quadrupole, lattice, 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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MOPAB215	Using ICA for Retrieving Teng Parameters	GUI, coupling, factory, FEL	711
	A. Lauterbach IAP, Frankfurt am Main, Germany G. Franchetti GSI, Darmstadt, Germany
	The blind source separation (BSS) method of Independent Component Analysis (ICA) is explored as a new approach for the reconstruction of the transfer matrix of Linear Coupling Parameterization. ICA is a method to detangle independent signals out of several measurements of their mixtures. In BSS-calculations, it is usually not possible to retrieve the mixing matrix, for the source signals, as well as the matrix, are unknown. Combining the parameterization model of D.A. Edwards and L.C. Teng with the standard ICA approach, it is though possible to retrieve the mixing matrix, as the form of the original uncoupled motion is known. At the same time arises the possibility to recalculate the parameters of Edwards and Teng through a system of equations of the one turn map components. It can be shown as a proof of concept, that the parameters can be reconstructed up to high accuracy for a simulated, non-perturbed signal.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB215
About •	paper received ※ 10 May 2021 paper accepted ※ 31 May 2021 issue date ※ 23 August 2021
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MOPAB216	20-24 GeV FFA CEBAF Energy Upgrade	linac, booster, lattice, 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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MOPAB217	A Storage Ring for MESA	target, experiment, simulation, operation	719
	C.P. Stoll, A. Meseck KPH, Mainz, Germany B. Ledroit HIM, Mainz, Germany
	The Mainz Energy-recovering Superconducting Accelerator (MESA) is an Energy Recovery Linac (ERL) facility under construction at the Johannes Gutenberg-University in Mainz. It provides the opportunity for precision physics experiments with a 1 mA c.w. electron beam in its initial phase. In this phase experiments with unpolarised, high density 10¹⁹ atoms cm² gas jet targets are foreseen at the Mainz Gas Internal Target Experiment (MAGIX). To allow experiments with thin polarised gas targets with sufficiently high interaction rates in a later phase, the beam current has to be increased to up to 100 mA, which would pose significant challenges to the existing ERL machine. Thus, it is proposed here to use MESA in pulsed operation with a repetition rate of several kHz to fill a storage ring, providing a quasi c.w. beam current to a thin gas target. For this purpose, the existing optics need to be extended and adapted, a suitable injection and extraction scheme is necessary and beam target interaction must be investigated. First considerations on these topics are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB217
About •	paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 21 August 2021
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MOPAB229	Compensations of Third-Order Resonances in J-PARC MR	resonance, sextupole, operation, survey	744
	T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa KEK, Tokai, Ibaraki, Japan
	The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 10¹³ protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (ν_x, ν_y) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is ν_x-2ν_y=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3ν_x=64 and ν_x+2ν_y=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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MOPAB230	The Optics Design for the Final Focus System of CLIC 380 GeV	luminosity, sextupole, quadrupole, target	748
	A. Pastushenko, R. Tomás García CERN, Geneva, Switzerland A. Faus-Golfe Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	The first stage of the Compact Linear Collider (CLIC) is planned to be at the center-of-mass energy of 380 GeV. The final focus system (FFS) was re-optimized for this energy and for L* of 6 m (distance between the Interaction Point (IP) and the last quadrupole, QD0). Furthermore, the FFS optics was optimized for the vertical beta-function of 70 microns to approach the Hourglass effect limit. This paper reports the exploration of shortening the Final Doublet (FD) within the FFS to reduce the chromaticity. In addition, an alternative optics design is investigated with a different dispersion profile along the FFS, which outperforms the previous optics with the same β^*, increasing luminosity by 5 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB230
About •	paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 11 August 2021
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MOPAB231	Tunability Study of the Ultra-Low β* Optics at ATF2 with New Octupole Setup and Tuning Knobs	octupole, alignment, simulation, quadrupole	752
	A. Pastushenko, R. Tomás García CERN, Geneva, Switzerland A. Faus-Golfe Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France K. Kubo, S. Kuroda, T. Naito, T. Okugi, N. Terunuma, R.J. Yang KEK, Ibaraki, Japan
	The main goal of the Accelerator Test Facility 2 (ATF2) is to demonstrate the feasibility of future linear colliders’ final focus systems. The Ultra-low β^* optics of ATF2 is designed to have the same chromaticity level as CLIC. To ease the tuning procedure, a pair of octupoles was installed in ATF2 in 2017. This paper reports the optimizations performed to the octupoles’ setup for Ultra-low β^* optics including the new alignment technique, based on the waist shift and the new tunning knobs constructed for this optics. The full tuning procedure including the static errors is simulated for this setup.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB231
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 12 August 2021
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MOPAB234	Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields	dipole, focusing, simulation, closed-orbit	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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MOPAB235	Transverse 2d Phase-Space Tomography Using Beam Position Monitor Data of Kicked Beams	emittance, electron, betatron, storage-ring	763
	K. Hwang, C.E. Mitchell, R.D. Ryne LBNL, Berkeley, California, USA
	Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231 The time-series Beam Position Monitor (BPM) data of kicked beam is a function of lattice parameters and beam parameters including phase-space density. The decoherence model using the first-order detuning parameter has an exact solution when the beam is Gaussian. We parameterize the beam phase-space density by multiple Gaussian kernels of different weights, means, and sizes to formulate the inverse problem for 2D phase-space tomography. Numerical optimization and Bayesian inference are used to infer the beam density.
	Poster MOPAB235 [1.253 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB235
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 01 September 2021
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MOPAB245	Theoretical Analysis of the Conditions for an Isochronous and CSR-Immune Triple-Bend Achromat with Stable Optics	emittance, dipole, radiation, synchrotron-radiation	786
	C. Zhang, Y. Jiao IHEP, Beijing, People’s Republic of China C.-Y. Tsai HUST, Wuhan, 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), National Key R&D Program of China (No. 2016YFA0401900) Transport of high-brightness beams with minimum degradation of the phase space quality is pursued in modern accelerators. For the beam transfer line which commonly consists of bending magnets, it would be desirable if the transfer line can be isochronous and coherent synchrotron radiation (CSR)-immune. For multi-pass transfer line, the achromatic cell designs with stable optics would bring great convenience. In this paper, based on the transfer matrix formalism and the CSR point-kick model, we report the detailed theoretical analysis and derive the condition for a triple-bend achromat with stable optics in which the first-order longitudinal dispersion (i.e., R56) and the CSR-induced emittance growth can be eliminated. The derived condition suggests a new way of designing the bending magnet beamline that can be applied to the free-electron laser (FEL) spreader and energy recovery linac (ERL) recirculation loop.
	Poster MOPAB245 [0.530 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB245
About •	paper received ※ 12 May 2021 paper accepted ※ 08 June 2021 issue date ※ 27 August 2021
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MOPAB258	Corrections of Non-Linear Field Errors with Asymmetric Optics in LHC and HL-LHC Insertion Regions	simulation, hadron, collider, insertion	817
	J. Dilly, E.H. Maclean, R. Tomás García CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research. Existing correction schemes to locally suppress resonance driving terms in the error-sensitive high-beta regions of the LHC and HL-LHC have operated on the assumption of symmetric beta-functions of the optics in the two rings. As this assumption can fail for a multitude of reasons, such as inherently asymmetric optics and unevenly distributed errors, an extension of this correction scheme has been developed removing the need for symmetry by operating on the two separate optics of the beams at the same time. Presented here is the impact of this novel approach on dynamic aperture as an important measure of particle stability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB258
About •	paper received ※ 10 May 2021 paper accepted ※ 23 July 2021 issue date ※ 16 August 2021
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MOPAB259	Corrections of Feed-Down of Non-Linear Field Errors in LHC and HL-LHC Insertion Regions	simulation, hadron, collider, insertion	821
	J. Dilly, E.H. Maclean, R. Tomás García CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research. The optics in the insertion regions of the LHC and its upgrade project the High Luminosity LHC (HL-LHC) are very sensitive to local magnetic errors, due to the extremely high beta-functions present. In collision optics, the non-zero closed orbit in the same region leads to a "feed-down" of high-order errors to lower orders, causing additional effects detrimental to beam lifetime. An extension to the proven method for correcting these errors by locally suppressing resonance driving terms has been undertaken, not only taking this feed-down into account, but also adding the possibility of utilizing it such that the powering of higher-order correctors will compensate for lower order errors. The impact of these corrections on measures of particle stability, namely dynamic aperture and amplitude detuning are presented in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB259
About •	paper received ※ 10 May 2021 paper accepted ※ 23 July 2021 issue date ※ 15 August 2021
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MOPAB260	Optics Corrections with LOCO on Sirius Storage Ring	quadrupole, storage-ring, coupling, MMI	825
	M.B. Alves LNLS, Campinas, Brazil
	Sirius is a 4th generation 3GeV synchrotron light source at the Brazilian Center for Research in Energy and Materials (CNPEM). In this work, we report the results of linear optics and coupling corrections during the commissioning of Sirius storage ring, using the Linear Optics from Closed Orbits (LOCO) algorithm. Beam-based measurements were performed to verify independently the impact of corrections on storage ring parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB260
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 30 August 2021
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MOPAB269	Three Approaches for Complete Measurement of the Transverse Beam Optics Along the Fermilab Muon Campus Extraction Line	quadrupole, extraction, dipole, real-time	854
	B.D. Simons, M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA D. Stratakis, M.J. Syphers Fermilab, Batavia, Illinois, USA
	Funding: This work was supported through grant DE-SC0020379 with the United States Department of Energy. Traditionally, the process of measuring the optical parameters of a beamline has employed the use of one of two standard methods, namely the three-screen method or a quadrupole magnet scan. Both require either an area of zero dispersion to perform the measurements or knowledge of the dispersion function and momentum spread beforehand in order to provide accurate results. There is however a third method that can be used to measure the standard optical parameters, the beam parameters, the dispersion function, and the momentum spread simultaneously. This method, aptly named the six-screen method, is an extension of the more standard three-screen method. Utilizing the simulation environment of G4beamline, we simulated the 8 GeV proton beam in the M4 beamline and measured the optical and beam parameters using the two standard approaches. Those results were then used as a reference to check the viability of employing the less standard six-screen method in the M4 line. If shown to be a viable option, the six-screen method could be used to retrieve the dispersion function and momentum spread of the beam without needing to change the energy of the beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB269
About •	paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021
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MOPAB417	Preliminary Study of a Large Energy Acceptance FFA Beam Delivery System for Particle Therapy	proton, focusing, superconducting-magnet, radiation	1256
	J.S.L. Yap, E.R. Higgins, S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia
	The availability and use of ion beams for radiotherapy has grown significantly, led by technological developments to exploit the dosimetric advantages offered by charged particles. The benefits of particle therapy (PT) are well identified however its utilisation is still limited by high facility costs and technological challenges. A possibility to address both of these can be considered by improvements to the beam delivery system (BDS). Existing beamlines and gantries transport beams with a momentum range of ±1% and consequently, adjustments in depth or beam energy require all the magnetic fields to be changed. The speed to switch energies is a limiting constraint of the BDS and a determinant of the overall treatment time. A novel concept using fixed field alternating gradient (FFA) optics enables a large energy acceptance (LEA) as beams of varying energies can traverse the beamline at multiple physical positions given the same magnetic field. This presents the potential to provide faster, higher quality treatments at lower costs, with the capability to deliver advanced PT techniques such as multi-ion therapy. We explore the applicability and benefits of a LEA BDS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB417
About •	paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 15 August 2021
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TUPAB001	DAΦNE Commissioning for SIDDHARTA-2 Experiment	luminosity, collider, feedback, positron	1322
	C. Milardi, D. Alesini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, A. D’Uffizi, A. De Santis, C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, G. Franzini, A. Gallo, S. Incremona, A. Michelotti, L. Pellegrino, L. Piersanti, R. Ricci, U. Rotundo, L. Sabbatini, A. Stecchi, A. Stella, A. Vannozzi, M. Zobov INFN/LNF, Frascati, Italy J. Chavanne, G. Le Bec, P. Raimondi ESRF, Grenoble, France
	DAΦNE, the Frascati lepton collider, has completed the preparatory phase in order to deliver luminosity to the SIDDHARTA-2 detector. DAΦNE colliding rings rely on a new interaction region, which implements the well-established Crab-Waist collision scheme, and includes a low-beta section equipped with newly designed permanent magnet quadrupoles, and vacuum components. Diagnostics tools have been improved, especially the ones used to keep under control the beam-beam interaction. The horizontal feedback in the positron ring has been potentiated in order to achieve a higher positron current. Luminosity diagnostics have been also updated so to be compatible with the new detector design. The commissioning was initially focused on recovering the optimal dynamical vacuum conditions, outlining alignment errors, and optimizing ring optics. For this reason, a detuned optics, featured by relaxed low-b condition at the interaction point and Crab-Waist Sestupoles off, has been applied. In a second stage a low-b optics has been implemented to test collisions with a preliminary setup of the experiment detector. Machine preparation and the first luminosity results are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB001
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021
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TUPAB004	Comparison of Accelerator Codes for Simulation of Lepton Colliders	radiation, lattice, emittance, 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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TUPAB006	The Impact of Beam Position Monitor Tilts on Coupling Measurements	coupling, resonance, simulation, quadrupole	1342
	L. van Riesen-Haupt, R. Tomás García CERN, Meyrin, Switzerland
	The measurement and correction of coupling resonance driving terms is a key tool for improving the performance of synchrotrons. These terms are measured by exciting the beam and observing the subsequent motion in the horizontal and vertical planes through beam position monitors. This paper outlines the impact of tilt errors in these monitors to the distortion of the amount of coupling measured between the planes and how the computation of the resonance driving terms is affected by these tilts. It also attempts to use these results for mimicking tilt errors in simulations and discusses how discrepancies in measured resonance driving terms could be used to estimate the tilt errors that cause them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB006
About •	paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 12 August 2021
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TUPAB007	A Correction Scheme for the Magnet Imperfection on the CEPC Collider Ring	lattice, quadrupole, emittance, alignment	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 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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TUPAB009	SuperKEKB Optics Measurements Using Turn-by-Turn Beam Position Data	closed-orbit, 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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TUPAB010	Impact of Bunch Current on Optics Measurements in SuperKEKB	damping, impedance, quadrupole, radiation	1356
	J. Keintzel, R. Tomás García, F. Zimmermann CERN, Geneva, Switzerland T. Ishibashi, H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, S. Terui, M. Tobiyama, R.J. Yang, D. Zhou KEK, Ibaraki, Japan
	SuperKEKB has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} and aims at reaching a target luminosity of about 6 × 10³⁵ \si{cm^-2s^-1}. To accomplish this goal it is planned to increase beam currents up to §I{3.6}{A} and §I{2.6}{A} for the positron and the electron ring, respectively. Increasing the beam currents and, in particular, the number of leptons per bunch, can impact the optics parameters obtained by turn-by-turn measurements, such as the betatron tune or phase advance. Optics measurements performed at various bunch currents can give first indications of possible intensity dependent effects. In this paper, the effect of varying bunch current on optics measurements at SuperKEKB is explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB010
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 30 August 2021
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TUPAB011	Momentum Compaction Factor Measurements in the Large Hadron Collider	quadrupole, synchrotron, collider, hadron	1360
	J. Keintzel, L. Malina, R. Tomás García CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) at CERN and its planned luminosity upgrade, the High Luminosity LHC (HL-LHC) demand well-controlled on- and off-momentum optics. Optics measurements are performed by analysing Turn-by-Turn (TbT) data of excited beams. Different techniques to measure the momentum compaction factor from these data are explored, taking into account the possibility to combine them with RF-voltage scans in future experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB011
About •	paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021
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TUPAB040	Design Concept for the Second Interaction Region for Electron-Ion Collider	electron, detector, proton, dipole	1435
	B.R. Gamage, V. Burkert, R. Ent, Y. Furletova, D.W. Higinbotham, A. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, D. Romanov, T. Satogata, A. Seryi, A.V. Sy, C. Weiss, M. Wiseman, W. Wittmer, Y. Zhang JLab, Newport News, Virginia, USA E.C. Aschenauer, J.S. Berg, A. Jentsch, A. Kiselev, C. Montag, R.B. Palmer, B. Parker, V. Ptitsyn, F.J. Willeke, H. Witte BNL, Upton, New York, USA C. Hyde ODU, Norfolk, Virginia, USA P. Nadel-Turonski SBU, Stony Brook, New York, USA
	Funding: Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 and Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The possibility of two interaction regions (IRs) is a design requirement for Electron-Ion Collider (EIC). There is also a significant interest from the nuclear physics community to have a 2nd IR with measurement capabilities complementary to those of the 1st IR. While the 2nd IR will be in operation over the entire energy range of ~20GeV to ~140GeV center of mass (CM). The 2nd IR can also provide an acceptance coverage complementary to that of the 1st. In this paper, we present a brief overview and the current progress of the 2nd IR design in terms of the parameters, magnet layout, and beam dynamics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB040
About •	paper received ※ 24 May 2021 paper accepted ※ 31 August 2021 issue date ※ 30 August 2021
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TUPAB048	HMBA Optics Correction Experience at ESRF	lattice, 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, lattice, SRF	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, lattice, injection	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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TUPAB059	Measurement of the Advanced Photon Source Lifetime at Different Level of Beta-Beating	quadrupole, betatron, storage-ring, simulation	1496
	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. Linear optics correction of a particle accelerator may not be perfect due to the existence of different errors sources in response matrix measurements and optics correction process. Previous numerical simulation study has shown that the single particle beam dynamics performance may be highly correlated with the level of residual beta-beating. In this paper, the machine study results on beam lifetime of the APS storage ring is presented. The experiment is performed at different level of predefined beta-beating with negligible betatron tunes variations. As expected, the measured beam lifetime has an inverse correlation with the level of beta-beating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB059
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 16 August 2021
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TUPAB106	Simulation Calculations of Compact THz Facility at IUAC, New Delhi	undulator, radiation, simulation, electron	1633
	J. Karmakar, S. Ghosh IUAC, New Delhi, India
	A compact THz radiation source based on the principle of pre-bunched Free Electron Laser is at the commissioning stage at Inter University Accelerator Centre (IUAC), New Delhi. The facility will generate low emittance train of electron micro-bunches (2, 4, 8 or 16 numbers) from a RF photo-cathode gun in the energy range of 4 to 8 MeV and inject into a compact undulator to generate coherent THz radiation in the frequency range of ~0.18 to 3.0 THz. To optimize the intensity at a given frequency, the beam bunching factor and the betatron oscillation amplitude in the non-wiggling plane of the electronμbunches inside the undulator has been maximized and minimized respectively. The paper presents the optimized beam optics simulation results for two frequencies viz 0.5 and 2 THz. The on-axis radiation spectral intensity computed by in-house developed code using the trajectory data of the beam optics simulation is also presented for the two frequencies.
	Poster TUPAB106 [1.208 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB106
About •	paper received ※ 18 May 2021 paper accepted ※ 31 August 2021 issue date ※ 12 August 2021
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TUPAB117	Eigenmode Decomposition for Free-Electron Lasers Using Bayesian Analysis	laser, FEL, simulation, distributed	1666
	P. Liu, W. Li, Y.K. Wu, J. Yan FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. Laser beams from an optical cavity, such as free-electron laser (FEL) resonators, are typically a mixture of the cavity’s eigenmodes, such as the Hermite-Gaussian (HG) modes or Laguerre-Gaussian (LG) modes. Robust evaluation of the eigenmode spectrum of a multimode laser beam has various applications in laser development, research, and utilization. In this work, a general eigenmode decomposition method for a multimode laser beam has been developed based on Bayesian analysis. This problem is transformed into a linear system and then solved using a Gaussian probabilistic model. Using Bayesian analysis, prior knowledge about the mode content is further incorporated into the solution to improve the results for laser beams contaminated with complex disturbances. The decomposition of the beam image from the incoherent intensity addition of HG modes is discussed with different types of noise or disturbances. The simulation results have been used to show the robustness of this method. This method can be straightforwardly extended into other cases such as the wavefront decomposition into the coherent superposition of HG and LG modes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB117
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 01 September 2021
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TUPAB171	Linear Transfer Matrix of a Half Solenoid	solenoid, emittance, coupling, ion-source	1789
	P.F. Ma, X. Guan, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng TUB, Beijing, People’s Republic of China
	Solenoid magnets can provide strong transverse focusing to electrons and ions with relatively small energies. For the ECR heavy-ion source, the ions are extracted at the central area of the solenoid, the beam is coupled at the exit of the source. The coupling caused by the solenoids can lead to the growth of projected transverse emittance, which has been widely studied with great interest. It is important to study the transfer matrix of a half solenoid to study the beam optics in an ECR souce, thus the property of the beam can be given. Based on the transfer matrix calculation, the summary of the linear transfer matrix of a half solenoid can be given. The beam optics in a half solenoid is studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB171
About •	paper received ※ 18 May 2021 paper accepted ※ 28 June 2021 issue date ※ 29 August 2021
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TUPAB195	Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning	MMI, controls, neutron, resonance	1865
	Y.W. An, Y. Li, S.Y. Xu, Y. Yuan IHEP, Beijing, People’s Republic of China M.T. Li IHEP CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.
	Poster TUPAB195 [2.279 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195
About •	paper received ※ 13 May 2021 paper accepted ※ 17 June 2021 issue date ※ 01 September 2021
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TUPAB208	FETS-FFA Ring Study	lattice, injection, 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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TUPAB217	Effect of Undulators on Transverse Resonant Island Orbits	undulator, operation, diagnostics, dipole	1927
	E.C.M. Rial, J. Bahrdt, P. Goslawski, A. Meseck, M. Ries, M. Scheer HZB, Berlin, Germany
	For one week in October 2020, BESSY II offered a Two Orbit mode to users for the first time. In this Two Orbit mode, the existence of transverse resonant island buckets* are exploited to store a second beam in the storage ring as an ’island orbit’, away from the primary beam axis. This mode was offered with free range of motion of the 12 out of vacuum undulators installed at the BESSY II ring. Diagnostics of the island orbit were limited to a single camera monitoring bending magnet radiation from a single dipole. A significant motion of the island orbit was observed on this diagnostic and correlated with undulator motion. This observation is reported, and simulations presented to demonstrate how this motion could arise. Correction schemes are suggested and discussed. Two Orbit - a report on the first scheduled week of TRIBs user operation at BESSY II, M. Ries et al, these proceedings *Proc. IPAC 2016, Busan, S Korea, paper THPMR017, p. 3427
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB217
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021
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TUPAB219	Equilibrium and Nonlinear Beam Dynamics Parameters From Sirius Turn-by-Turn BPM Data	experiment, emittance, betatron, factory	1935
	X.R. Resende, M.B. Alves, L. Liu, F.H. de Sá LNLS, Campinas, Brazil
	A considerable amount of beam information is conveyed by Turn-by-Turn (TbT) data of Beam Position Monitors (BPM). In this work such data sets are analyzed for Sirius, the Brazilian 4th Generation 3GeV synchrotron light source. In particular, equilibrium and non-linear beam dynamics parameters determining decoherence patterns in TbT position data are estimated and compared with corresponding values of the nominal storage ring model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB219
About •	paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 15 August 2021
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TUPAB224	Non-Linear Variation of the Beta-Beating Measured From Amplitude	octupole, simulation, resonance, target	1949
	T. Pugnat, B. Dalena CEA-IRFU, Gif-sur-Yvette, France A. Franchi ESRF, Grenoble, France R. Tomás García CERN, Geneva, Switzerland
	Accelerator physics needs advanced modeling and simulation techniques, for beam stability studies but also for the measurement of beam parameters like the Twiss parameters. A deeper understanding of magnetic field non-linearities effects will greatly help in the improvement of future circular collider design, performance, and diagnostics. This paper studies the variation of the \beta-beating with the action of the particle generated by non-linear Resonance Driving Terms, both from a theoretical and an experimental point of view.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB224
About •	paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 21 August 2021
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TUPAB228	IOTA Run 2 Beam Dynamics Studies in Nonlinear Integrable Systems	octupole, experiment, lattice, 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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TUPAB236	Progress on the Electron Gun Design for a McMillan Electron Lens in the Fermilab Integrable Optics Test Accelerator (IOTA)	electron, gun, cathode, simulation	1988
	B.L. Cathey, G. Stancari 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. This paper covers the progress made so far in designing the first McMillan electron lens for the Fermilab IOTA ring. The novel design allows for an increase in tune spread without limiting the dynamic aperture due to its integrability. Shown are simulations for an electron gun design to generate the specific required current density distribution for the nonlinear integrable system in IOTA.
	Poster TUPAB236 [5.391 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB236
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021
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TUPAB311	Nonlinear Correctors Tuning for the Collector Ring Isochronous Mode	sextupole, betatron, controls, proton	2218
	M.A. Lyalin, I. Koop, D.B. Shwartz BINP SB RAS, Novosibirsk, Russia I. Koop, M.A. Lyalin, D.B. Shwartz NSU, Novosibirsk, Russia
	One of the operating modes for the Collector Ring (CR) under construction in Darmstadt is the isochronous mode, in which the captured ions circulate with an equal period regardless of their momentum. The measurement of the orbital period T by the time-of-flight sensors makes it possible to precisely determine the mass to the charge ratio of the ion under study. For this, the change of the circulation period dT should not exceed 1·10^-6 for dT/T in the entire momentum acceptance of the 0.62%. Modeling in the Strategic Accelerator Design code showed that without nonlinear effects compensation, the orbital period variation is 1·10^-5. In this work, the parameters of nonlinear correctors, which are sextupoles and octupoles in CR, are determined, necessary for the isochronous mode implementation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB311
About •	paper received ※ 29 May 2021 paper accepted ※ 16 June 2021 issue date ※ 14 August 2021
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TUPAB361	Study and Design of a Fast Switching Magnet for the MYRRHA Project	dipole, linac, proton, beam-transport	2356
	E. Froidefond, F. Bouly, P.-O. Dumont LPSC, Grenoble Cedex, France D. Vandeplassche SCK•CEN, Mol, Belgium
	Funding: Work supported by SCK•CEN, CNRS/IN2P3, Univ. Grenoble Alpes. The MYRRHA project aims at building an Accelerator Driven System demonstrator, which consists of two injectors and a superconducting linac. The proton beam from the first injector accelerated up to 17 MeV goes to the linac (600 MeV) through a Medium Energy Beam Transfer line (MEBT). Whereas in the meantime, the beam from the second injector is sent to a beam dump. In case of failure in the first injector, the beam of the awaiting injector is sent to the linac. A switching magnet located at the junction of the two injection lines performs this beam switch in less than 1.5 seconds. A magnetic design and a mechanical structure of this magnet proposed to the MYRRHA project are presented. *emmanuel.froidefond@lpsc.in2p3.fr
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB361
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021
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TUPAB407	A Novel Beam Optics Concept to Maximize the Transmission Through Cyclotron-based Proton Therapy Gantries	proton, emittance, quadrupole, simulation	2477
	V. Maradia, A.C. Giovannelli, A.L. Lomax, D. Meer, S. Psoroulas, J.M. Schippers, D.C. Weber PSI, Villigen PSI, Switzerland V. Maradia ETH, Zurich, Switzerland D.C. Weber University of Zurich, University Hospital, Zurich, Switzerland D.C. Weber KRO, Bern, Switzerland
	Funding: This work is funded by a PSI inter-departmental funding initiative (CROSS). Most of the conventional beam optics of cyclotron-based proton gantries were designed to provide point-to-point focus in both planes with an imaging factor between 1 and 2 from the entrance of the gantry to the patient. This means that a small beam size at the gantry entrance is required to achieve the required small beam size at the patient. Due to the typically used beam emittance, this in turn results in large beam divergence at the gantry entrance, increasing the possibility of beam losses along the gantry as the beam envelope gets close to the apertures. To maximize transmission through the gantry, we propose a novel beam optics concept using 3:1 imaging. It reduces the beam divergence at the gantry entrance by factor 3 while still achieving a small beam size at the patient. The beam envelope is better controlled and keeps clear of the apertures compared to the 1:1 or 1:2 imaging beam envelope. For PSI Gantry 2, the novel 3:1 imaging beam optics increase the proton beam transmission for lower energies by 40% compare to 1:1 imaging beam optics. The usage of small imaging factors can help to maximize transmission for different gantry lattices, thus reducing treatment times.
	Poster TUPAB407 [1.347 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB407
About •	paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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WEPAB001	Accelerator Challenges of the LHeC Project	electron, emittance, linac, proton	2570
	B.J. Holzer, K.D.J. André, O.S. Brüning CERN, Geneva, Switzerland S.A. Bogacz JLab, Newport News, Virginia, USA M. Klein The University of Liverpool, Liverpool, United Kingdom
	The LHeC project studies the design of a future electron-proton collider at CERN that will run in parallel to the standard LHC operation. For this purpose, the existing LHC storage ring will be combined with an Energy Recovery Linac (ERL), to accelerate electrons up to kinetic energy of 50 GeV. This concept - also applicable to the FCC-eh collider and studied at the PERLE project as prototype version - allows a peak luminosity of 10³⁴ cm^-2 s^-1. A sophisticated design of the RF structures, linacs, arcs, and interaction region is required. The electrons are accelerated and, after the interaction point, their energy is recovered through the same RF structures. While this energy recovery concept is a very promising approach, severe challenges are set by the layout of the interaction region, the beam separation concept and the design of the linac and arc lattice for the highest possible momentum acceptance. Emittance control and beam-beam effect of both, electron and proton beams, have been studied in front-to-end simulations and will be presented. We summarise the design principles of the ERL, the optimization of the arc lattice, and the main parameters of the project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB001
About •	paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 21 August 2021
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WEPAB026	Optics Measurements and Correction Plans for the HL-LHC	coupling, luminosity, dynamic-aperture, dipole	2656
	T.H.B. Persson, X. Buffat, F.S. Carlier, R. De Maria, J. Dilly, E. Fol, D. Gamba, H. Garcia Morales, A. García-Tabarés Valdivieso, M. Giovannozzi, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, P.K. Skowroński, F. Soubelet, R. Tomás García, F.F. Van der Veken, A. Wegscheider, D.W. Wolf, L. van Riesen-Haupt CERN, Geneva, Switzerland J.M. Coello de Portugal PSI, Villigen PSI, Switzerland
	The High Luminosity LHC (HL-LHC) will require stringent optics correction to operate safely and deliver the design luminosity to the experiments. In order to achieve this, several new methods for optics correction have been developed. In this article, we outline some of these methods and we describe the envisioned strategy of how to use them in order to reach the challenging requirements of the HL-LHC physics program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB026
About •	paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 30 August 2021
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WEPAB027	Optics Correction Strategy for Run 3 of the LHC	coupling, dipole, MMI, quadrupole	2660
	T.H.B. Persson, R. De Maria, J. Dilly, E. Fol, H. Garcia Morales, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, F. Soubelet, R. Tomás García, A. Wegscheider, D.W. Wolf, L. van Riesen-Haupt CERN, Geneva, Switzerland J.F. Cardona UNAL, Bogota D.C, Colombia
	The Run 3 of the LHC will continue to provide new challenges for optics corrections. In order to succeed and go beyond what was achieved previously, several new methods to measure and correct the optics have been developed. In this article we describe these methods and outline the plans for the optics commissioning in 2022.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB027
About •	paper received ※ 17 May 2021 paper accepted ※ 12 July 2021 issue date ※ 11 August 2021
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WEPAB074	A Distributed Sextupoles Lattice for the ALBA Low Emittance Upgrade	lattice, emittance, sextupole, injection	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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WEPAB079	Optics Studies on the Operation of a New Wiggler and Bunch Shortening at the DELTA Storage Ring	wiggler, cavity, storage-ring, operation	2772
	B. Büsing, P. Hartmann, A. Held, S. Khan, C. Mai, D. Schirmer, G. Schmidt DELTA, Dortmund, Germany
	Funding: Work supported by Deutsche Forschungsgemeinschaft via project INST 212/330-1 AOBJ: 619186 The 1.5-GeV electron storage ring DELTA is a synchrotron light source operated by the TU Dortmund University. Radiation from hard X-rays to the THz regime is provided by dipole magnets and insertion devices like undulators and wigglers. To provide even shorter wavelengths, a new 22-pole superconducting 7-T wiggler has been installed. The edge focusing of the wiggler has a large impact on the linear optics of the storage ring. Measurements regarding its influence and simulations were performed. In addition, a second radiofrequency (RF) cavity has been installed to compensate the increased energy loss per turn due to the new wiggler. As a consequence of the higher RF power, the electron bunches are shorter compared to the old setup with only one cavity. In view of reducing the bunch length even more, studies of the storage ring optics with reduced momentum compaction factor were performed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB079
About •	paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 01 September 2021
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WEPAB088	Transverse Beam Emittance Measurement by Undulator Radiation Power Noise	radiation, emittance, undulator, synchrotron	2794
	I. Lobach University of Chicago, Chicago, Illinois, USA A. Halavanau, Z. Huang SLAC, Menlo Park, California, USA K. Kim ANL, Lemont, Illinois, USA V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA
	Generally, turn-to-turn power fluctuations of incoherent spontaneous synchrotron radiation in a storage ring depend on the 6D phase-space distribution of the electron bunch. In some cases, if only one parameter of the distribution is unknown, this parameter can be determined from the measured magnitude of these power fluctuations. In this contribution, we report the results of our experiment at the Integrable Optics Test Accelerator (IOTA) storage ring, where we carried out an absolute measurement (no free parameters or calibration) of a small vertical emittance (5–15 nm rms) of a flat beam by this new method, under conditions, when the small vertical emittance is unresolvable by a conventional synchrotron light beam size monitor.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB088
About •	paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 12 August 2021
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WEPAB180	Design and Beam Dynamics Studies of a Novel Compact Recoil Separator Ring for Nuclear Research with Radioactive Beams	ISOL, dipole, quadrupole, operation	3031
	J. Resta-López UVEG, Burjasot (Valencia), Spain A.P. Foussat, G. Kirby CERN, Geneva, Switzerland I. Martel University of Huelva, Huelva, Spain V. Rodin The University of Liverpool, Liverpool, United Kingdom V. Rodin Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was supported by the Generalitat Valenciana under grant agreement CIDEGENT/2019/058 The recent development of radioactive beam facilities has significantly expanded the capabilities for investigating the structure of the atomic nucleus and the nuclear interaction. For instance, the HIE-ISOLDE facility at CERN delivers presently the largest range of low-energy radioactive beam available worldwide. This energy range is ideal for the study of nuclear structure, low-energy dynamics and astrophysics by using nucleon transfer, Coulomb excitation and deep inelastic reactions. All these studies require an efficient and high-resolution recoil separator for the clear identification of medium and large mass reaction fragments. To meet these needs, we propose a versatile recoil separator for radioisotopes based on a compact storage ring, the Isolde Superconducting Recoil Separator (ISRS) formed of superconducting combined-function nested magnets with both, bending and focusing/defocusing functions. The ISRS is designed to operate in high momentum acceptance and isochronous modes. In this paper, we present the optics design and detailed beam dynamics studies for the performance characterisation.
	Poster WEPAB180 [3.619 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB180
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 31 August 2021
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WEPAB185	Target Bypass Beam Optics for Future High Intensity Fixed Target Experiments in the CERN North Area	target, experiment, proton, quadrupole	3046
	G.L. D’Alessandro, D. Banerjee, J. Bernhard, M. Brugger, N. Doble, L. Gatignon, A. Gerbershagen, B. Rae, F.M. Velotti CERN, Meyrin, Switzerland S.M. Gibson JAI, Egham, Surrey, United Kingdom
	Several of the proposed experiments for operation at the K12 beam line would profit from significant beam intensity increase. Among those, there is the KLEVER experiment that would require an intensity of 2x10¹³ protons per 4.8 s long spill. The main goal of the experiment is to measure BR(KL->pi0 nu nu) to test the Standard Model structure by itself, and in combination with results from NA62 for BR(K±>pi+ nu nu). NA62 could also profit from higher intensities, and could be run in a new configuration called NA62HI(gher intensity). In the current configuration the beam is transported from the SPS to the TT24 beamline. This beamline leads to the T4 target that attenuates the beam for P42. After T4 the beam is directed into the P42 beamline before impinging on the T10 target and creating the particles necessary for the experiment. Those are finally transported to the detector via K12. This paper presents the idea of partially bypassing T4 and changing the P42 beamline configuration in order to have a sufficiently small beam size at the T10 target for both KLEVER and NA62-HI. Optics studies are developed in MADX and the AppLE.py, software developed at CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB185
About •	paper received ※ 17 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021
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WEPAB279	On Wire-Corrector Optimization in the HL-LHC and the Appearance of Special Aspect Ratios	target, coupling, insertion, resonance	3297
	D. Kaltchev TRIUMF, Vancouver, Canada
	For the two high-luminosity insertions of the Large Hadron Collider (HL-LHC) current bearing wire correctors are intended to mitigate the detrimental effect of long-range beam-beam interactions. With respect to finding the optimum longitudinal location of the wire, two special locations corresponding to the special values 2 and 1/2 of the beta-function aspect ratio have been previously shown to provide simultaneous cancellation of multiple two-dimensional Resonance Driving Terms. This paper attempts to explain the appearance of such special aspect ratios.
	Poster WEPAB279 [1.238 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB279
About •	paper received ※ 14 May 2021 paper accepted ※ 19 July 2021 issue date ※ 13 August 2021
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WEPAB280	Two-Dimensional Beam-Beam Invariant with Applications to HL-LHC	resonance, closed-orbit, lattice, luminosity	3301
	D. Kaltchev TRIUMF, Vancouver, Canada
	Long-range beam-beam interactions represent the most severe limitation on the performance and achievable luminosity of circular collider. The paper presents a two-dimensional nonlinear Courant Snyder Invariant derived to first order in the beam-beam perturbation and based on the two-dimensional coefficients in the Fourier expansion of the Beam-beam Hamiltonian. Its validity in case of HL-LHC lattices with realistic beam-beam setup is verified with MadX tracking.
	Poster 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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WEPAB302	COSY Machine-Model Optimization	dipole, operation, simulation, betatron	3375
	I. Bekman, J.H. Hetzel FZJ, Jülich, Germany
	Funding: Helmholtz Association Successful operation of a particle accelerator requires accompanying model calculations. The model helps in understanding the machine and predicts the impact of a change in the settings (e.g. current of magnetic elements). For the COoler SYnchrotron (COSY) at Research Center Jülich the accelerator simulation software MAD-X is used to model the machine. The model parameters are steadily being improved based on various manual adjustments and analytical studies, however are hardly optimized all at once. This can be improved with machine learning methods. The model is used to predict measurable quantities, like Orbit Response Matrix (ORM) or betatron tunes. Several observables for different particle energies have been measured recently and the corresponding machine settings are available. We describe the effort to improve the agreement between measured and calculated ORMs and hence improve the agreement between model and (real) machine and report on the optimization using a multivariate algorithm (e.g. genetic algorithm). This facilitates the setup of COSY and will allow to perform high precision experiments e.g. a measurement of an electric dipole moment of deuterons at COSY.
	Poster WEPAB302 [1.905 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB302
About •	paper received ※ 14 May 2021 paper accepted ※ 28 July 2021 issue date ※ 20 August 2021
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WEPAB383	An Evolutionary Algorithm Approach to Multi-Pass ERL Optics Design	linac, quadrupole, focusing, simulation	3610
	I. Neththikumara, T. Satogata ODU, Norfolk, Virginia, USA R.M. Bodenstein, S.A. Bogacz, T. Satogata JLab, Newport News, Virginia, USA A. Vandenhoeke ULB, Bruxelles, Belgium
	Funding: This material is based upon work supported by the U.S. Department of Energy under contract DE-AC05-06OR23177. An Energy Recovery Experiment at CEBAF (ER@CEBAF) is aimed at demonstrating high energy, low current, multi-pass energy recovery at the existing 12 GeV CEBAF accelerator. The beam break-up instability, limiting the maximum beam current, can be controlled through minimizing beta functions for the lowest energy pass, which gives a preference to strongly focusing optics, e.g. a semi-periodic FODO lattice. On the other hand, one needs to limit beta function excursions, caused by under focusing, at the higher energy passes, which in turn favors weakly focusing linac optics. Balancing both effects is the main objective of proposed multi-pass linac optics optimization. Here, we discuss an optics design process for ER@CEBAF transverse optics using a genetic algorithm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB383
About •	paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 15 August 2021
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WEPAB399	Applications of the Local Observable in Future Optics Measurements in HL-LHC and PETRA III	lattice, 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

Paper

Title

Other Keywords

Page

MOXB02

First Results of the IOTA Ring Research at Fermilab

experiment, electron, lattice, 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

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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MOPAB006

Optics Configurations for Improved Machine Impedance and Cleaning Performance of a Multi-Stage Collimation Insertion

collimation, impedance, collider, scattering

57

R. Bruce, R. De Maria, M. Giovannozzi, N. Mounet, S. Redaelli
CERN, Geneva, Switzerland

For a two-stage collimation system, the betatron phase advance between the primary and secondary stages is usually set to maximise the absorption of secondary particles outscattered from the primary. Another constraint is the contribution to the ring impedance of the collimation system, which can be decreased through an optimized insertion optics, featuring large values of the beta functions. In this article we report on first studies of such an optics for the CERN LHC. In addition to a gain in impedance, we show that the cleaning efficiency can be improved thanks to the large beta functions, even though the phase advance is not set at the theoretical optimum.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB006

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paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 11 August 2021

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MOPAB007

Prospect for Interaction Region Local Coupling Correction in the LHC Run 3

coupling, quadrupole, luminosity, MMI

61

F. Soubelet, T.H.B. Persson, R. Tomás García
CERN, Geneva, Switzerland
O. Apsimon, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
O. Apsimon, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) and CERN.
Successful operation of large scale particle accelerators depends on the precise correction of unavoidable magnet field or alignment errors present in the machine. In the LHC Run 2, local linear coupling in the Interaction Regions (IR) has been proven to have a severe impact on beam size and hence the luminosity - up to a 50% decrease -, making its handling a target for Run 3 and High Luminosity LHC (HL-LHC). However, current measurement methods are not optimised for local IR coupling. In this contribution, an approach to accurately minimise IR local coupling based on correlated external variables such as the |C-| is proposed. The validity of the method is demonstrated through simulations and benchmarked against theoretical values, such as Resonance Driving Terms (RDTs) and Ripken parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB007

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paper received ※ 17 May 2021 paper accepted ※ 23 July 2021 issue date ※ 19 August 2021

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MOPAB012

Energy Deposition Study of the CERN HL-LHC Optics v1.5 in the ATLAS and CMS Insertions

luminosity, insertion, proton, radiation

76

M. Sabaté-Gilarte, F. Cerutti
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
The High Luminosity Large Hadron Collider (HL-LHC) is the approved CERN project aiming at further increasing the integrated luminosity of the LHC by a factor 10. As such, it implies a complete redesign of the experimental high-luminosity insertions of ATLAS and CMS. The progressive evolution of the new layout and optics requires a continuous analysis of the radiation environment, to which magnets and other equipment are exposed to. This is assured by means of Monte Carlo simulations of the collision debris on the evolving machine model. The latter featured several developments, such as the explicit inclusion of the cold protection diodes of the final focusing circuits as well as the crab cavities cryomodule. This work presents the most updated characterization of the radiation field with FLUKA and its impact in the insertion region and the dispersion suppressor of Point 1 and 5, for the HL-LHC optics v1.5 released in 2019. Various optimization and mitigation studies are highlighted, providing key information for maximizing the lifetime of new and present magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB012

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paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 21 August 2021

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MOPAB021

A Dispersive Quadrupole Scan Technique for Transverse Beam Characterization

quadrupole, SRF, emittance, booster

107

J. Kallestrup, M. Aiba
PSI, Villigen PSI, Switzerland
N. Carmignani, T.P. Perron
ESRF, Grenoble, France

Quadrupole scans are one of the standard techniques to characterize the transverse beam properties in transfer lines or linacs. However, in the presence of dispersion the usage of regular quadrupole scans will lead to erroneous estimates of the beam parameters. The standard solution to this problem is to measure the dispersion and then subtract it in the post-analysis of the quadrupole scan measurements assuming the design energy spread. Here we show that the dispersive contribution to the beam size can be included in the quadrupole scan procedure, forming a linear system of equations that can be solved to obtain both the betatronic and dispersive beam parameters. The method is tested at both the SLS and ESRF booster-to-ring transfer lines leading to reasonable estimates of the beam parameters.

Poster MOPAB021 [0.447 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB021

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

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MOPAB022

FailSim: A Numerical Toolbox for the Study of Fast Failures and Their Impact on Machine Protection at the CERN Large Hadron Collider

simulation, beam-losses, quadrupole, machine-protect

111

C. Hernalsteens, G. Sterbini, O.K. Tuormaa, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

The High Luminosity LHC (HL-LHC) foresees to reach a nominal, levelled luminosity of 5·10³⁴ cm^-2 s⁻¹ through a higher beam brightness and by using new equipment, such as larger aperture final focusing quadrupole magnets. The HL-LHC upgrade has critical impacts on the machine protection strategy, as the stored beam energy reaches 700 MJ for each of the two beams. Some failure modes of the novel active superconducting magnet protection system of the inner triplet magnets, namely the Coupling-Loss Induced Quench (CLIQ) systems, have been identified as critical. This paper reports on FailSim, a Python-language framework developed to study the machine protection impact of failure cases and their proposed mitigation. It provides seamless integration of the successive phases required by the simulation studies, i.e., verifying the optics, preparing and running a MAD-X instance for multiple particle tracking, processing and analysing the simulation results and summarising them with the relevant plots to provide a solid estimate of the beam losses, their location and time evolution. The paper also presents and discusses the result of its application on the spurious discharge of a CLIQ unit.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB022

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paper received ※ 18 May 2021 paper accepted ※ 31 May 2021 issue date ※ 18 August 2021

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MOPAB036

Different Operation Regimes at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)

operation, lattice, 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 MOPAB036 [1.477 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB036

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paper received ※ 13 May 2021 paper accepted ※ 08 June 2021 issue date ※ 29 August 2021

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MOPAB037

On Possibility of Alpha-buckets Detecting at the KIT Storage Ring KARA (Karlsruhe Research Accelerator)

storage-ring, operation, synchrotron, electron

167

A.I. Papash, T. Boltz, M. Brosi, A.-S. Müller, R. Ruprecht, P. Schreiber, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

Computer studies of longitudinal motion have been performed with the objective to estimate the possibility of detection of alpha-buckets at the KIT storage ring KARA (Karlsruhe Research Accelerator). The longitudinal equations of motion and the Hamiltonian were expanded to high order terms of the energy deviation of particles in a beam. Roots of third order equation for three leading terms of momentum compaction factor and free energy independent term were derived in a form suitable for analytical estimations. Averaged quadratic terms of closed orbit distortions caused by misalignment of magnetic elements in a ring lead to orbit lengthening independent of particle energy deviation. Particle transverse excursions were estimated and are taken into account. Simulations have been bench-marked on existing experiments at Metrology Light Source (MLS) in Berlin (Germany) and SOLEIL (France). Parameters of three simultaneous beams and alpha buckets at MLS and SOLEIL have been reproduced with high accuracy. A computer model of KARA was used to predict behavior and the dynamics of possible simultaneous beams in the ring.

Poster MOPAB037 [1.269 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB037

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paper received ※ 11 May 2021 paper accepted ※ 28 May 2021 issue date ※ 29 August 2021

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MOPAB047

A CAD Tool for Linear Optics Design: A Use Case Approach

controls, software, MMI, GUI

205

J. Bengtsson
HZB, Berlin, Germany
T.J.R. Nicholls, W.A.H. Rogers
DLS, Oxfordshire, United Kingdom

The formula relevant for linear optics design of synchrotrons are derived systematically from first principles, i.e., an exercise in Hamiltonian dynamics. Equipped with these, the relevant use cases are then captured; for a streamlined approach. To enable professionals, i.e., software engineers, to efficiently prototype & architect a CAD tool available to mechanical engineers since the mid-1960s. In other words, robust design of a modern synchrotron is an exercise in/pursuit of the art of Engineering-Science.

Poster MOPAB047 [1.059 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB047

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paper received ※ 17 May 2021 paper accepted ※ 28 May 2021 issue date ※ 15 August 2021

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MOPAB048

Robust Design and Control of the Nonlinear Dynamics for BESSY-III

lattice, controls, 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 MOPAB048 [1.202 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB048

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paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 27 August 2021

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MOPAB063

Commissioning Strategy for Diamond-II

MMI, lattice, 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

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paper received ※ 18 May 2021 paper accepted ※ 28 May 2021 issue date ※ 14 August 2021

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MOPAB115

ATS/STA Transfer Line Design for the ALS Upgrade Project (ALS-U)

injection, storage-ring, kicker, extraction

417

C. Sun, M.P. Ehrlichman, T. Hellert, M. Juchno, J.-Y. Jung, M. Mardenfeld, J.R. Osborn, G. Penn, C. Steier, C.A. Swenson, M. Venturini
LBNL, Berkeley, California, USA

At the Advanced Light Source Upgrade (ALS-U), an on-axis swap-out injection will be used to replenish depleted bunches in the storage ring with refreshed bunches from the full energy accumulator ring. To implement this scheme, two transfer lines are required between the storage ring and the accumulator ring: the accumulator-to-storage-ring (ATS) transfer line and the storage-ring-to-accumulator (STA) transfer line. The design of the ATS/STA transfer lines is a challenging task as they must fit within a tight injection region while also accommodating the storage and accumulator rings at different elevations. Moreover, the ATS/STA design needs to meet both the boundary conditions and optics requirements. In this paper, we will present a design option for these ATS/STA transfer lines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB115

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 15 August 2021

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MOPAB184

Unsupervised Learning Techniques for Tune Cleaning Measurement

ISOL, coupling, luminosity, quadrupole

624

H. Garcia Morales
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
E. Fol, R. Tomás García
CERN, Meyrin, Switzerland

Precise measurements of tune and its stability are crucial for various optics analyses in the LHC, e.g. for the determination of the beta star using K-modulation. LHC BBQ system provides tune measurements online and stores the tune data. We apply unsupervised machine learning techniques on BBQ tune data in order to provide an automatic outlier detection method for better measurements of tune shifts and unexpected tune jitters.

Poster MOPAB184 [0.354 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB184

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paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 11 August 2021

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MOPAB185

HL-LHC Local Linear Optics Correction at the Interaction Regions

quadrupole, interaction-region, simulation, lattice

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 MOPAB185 [0.469 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB185

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paper received ※ 14 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021

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MOPAB186

Comparison of Segment-by-Segment and Action-Phase-Jump Techniques in the Calculation of IR Local Corrections in LHC

quadrupole, simulation, interaction-region, MMI

632

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

The correction of the local optics at the Interaction Regions of the LHC is crucial to ensure a good performance of the machine. In this paper, we compare two different techniques for local optics correction: Action-Phase Jump and Segment-by-Segment techniques. The comparison is made in view of future machine configurations such as Run 3 LHC optics and HL-LHC optics.

Poster MOPAB186 [0.349 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB186

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paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021

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MOPAB213

Characterization of Linear Optics and Beam Parameters for the APS Booster with Turn-by-Turn BPM Data

booster, betatron, synchrotron, kicker

703

X. Huang, H. Shang, C. Yao
ANL, Lemont, Illinois, USA

We take turn-by-turn (TBT) BPM data on the energy ramp of the APS Booster, and analyze the data with the independent component analysis. The extraction kicker was used to excite the betatron motion. The linear optics of the machine is characterized with the TBT BPM data. We also analyze the decoherence pattern of the kicked beam, from which we are able to derive beam distribution parameters, such as the momentum spread.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB213

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paper received ※ 13 May 2021 paper accepted ※ 11 June 2021 issue date ※ 19 August 2021

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MOPAB214

Linear Optics Measurement for the APS Ring with Turn-by-Turn BPM Data

quadrupole, lattice, 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

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paper received ※ 12 May 2021 paper accepted ※ 09 June 2021 issue date ※ 01 September 2021

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MOPAB215

Using ICA for Retrieving Teng Parameters

GUI, coupling, factory, FEL

711

A. Lauterbach
IAP, Frankfurt am Main, Germany
G. Franchetti
GSI, Darmstadt, Germany

The blind source separation (BSS) method of Independent Component Analysis (ICA) is explored as a new approach for the reconstruction of the transfer matrix of Linear Coupling Parameterization. ICA is a method to detangle independent signals out of several measurements of their mixtures. In BSS-calculations, it is usually not possible to retrieve the mixing matrix, for the source signals, as well as the matrix, are unknown. Combining the parameterization model of D.A. Edwards and L.C. Teng with the standard ICA approach, it is though possible to retrieve the mixing matrix, as the form of the original uncoupled motion is known. At the same time arises the possibility to recalculate the parameters of Edwards and Teng through a system of equations of the one turn map components. It can be shown as a proof of concept, that the parameters can be reconstructed up to high accuracy for a simulated, non-perturbed signal.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB215

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paper received ※ 10 May 2021 paper accepted ※ 31 May 2021 issue date ※ 23 August 2021

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MOPAB216

20-24 GeV FFA CEBAF Energy Upgrade

linac, booster, lattice, 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

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

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MOPAB217

A Storage Ring for MESA

target, experiment, simulation, operation

719

C.P. Stoll, A. Meseck
KPH, Mainz, Germany
B. Ledroit
HIM, Mainz, Germany

The Mainz Energy-recovering Superconducting Accelerator (MESA) is an Energy Recovery Linac (ERL) facility under construction at the Johannes Gutenberg-University in Mainz. It provides the opportunity for precision physics experiments with a 1 mA c.w. electron beam in its initial phase. In this phase experiments with unpolarised, high density 10¹⁹ atoms cm² gas jet targets are foreseen at the Mainz Gas Internal Target Experiment (MAGIX). To allow experiments with thin polarised gas targets with sufficiently high interaction rates in a later phase, the beam current has to be increased to up to 100 mA, which would pose significant challenges to the existing ERL machine. Thus, it is proposed here to use MESA in pulsed operation with a repetition rate of several kHz to fill a storage ring, providing a quasi c.w. beam current to a thin gas target. For this purpose, the existing optics need to be extended and adapted, a suitable injection and extraction scheme is necessary and beam target interaction must be investigated. First considerations on these topics are presented here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB217

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paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 21 August 2021

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MOPAB229

Compensations of Third-Order Resonances in J-PARC MR

resonance, sextupole, operation, survey

744

T.Y. Yasui, S. Igarashi, T. Koseki, Y. Kurimoto, Y. Morita, K. Ohmi, Y. Sato, T. Shimogawa
KEK, Tokai, Ibaraki, Japan

The main ring synchrotron (MR) of the Japan Proton Accelerator Research Complex (J-PARC) provides high-power proton beams for the neutrino and hadron experiments. In the fast extraction (FX) operation, the beams are injected with the energy of 3 GeV and the intensity of 3.3 × 10¹³ protons per bunch, and accelerated to 30 GeV. Most of the beam losses are observed in the low-energy period, because the space charge tune spread is large, and crosses various kinds of resonances. In this study, the compensations of the third-order resonances are performed. The present operation tune is (ν_x, ν_y) = (21.35, 21.43) in FX operation. The nearest third-order structure resonance is ν_x-2ν_y=-21. It was clearly compensated by optimizing the phase advances in the arc sections. The compensation was confirmed by the aperture survey simulations and demonstrated by the three different experiments. The third-order nonstructure resonances near the operation tune are 3ν_x=64 and ν_x+2ν_y=64. They are simultaneously compensated by introducing four trim coils of the sextupole magnets. The beam loss was successfully reduced by adopting the compensations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB229

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paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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MOPAB230

The Optics Design for the Final Focus System of CLIC 380 GeV

luminosity, sextupole, quadrupole, target

748

A. Pastushenko, R. Tomás García
CERN, Geneva, Switzerland
A. Faus-Golfe
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

The first stage of the Compact Linear Collider (CLIC) is planned to be at the center-of-mass energy of 380 GeV. The final focus system (FFS) was re-optimized for this energy and for L* of 6 m (distance between the Interaction Point (IP) and the last quadrupole, QD0). Furthermore, the FFS optics was optimized for the vertical beta-function of 70 microns to approach the Hourglass effect limit. This paper reports the exploration of shortening the Final Doublet (FD) within the FFS to reduce the chromaticity. In addition, an alternative optics design is investigated with a different dispersion profile along the FFS, which outperforms the previous optics with the same β^*, increasing luminosity by 5 %.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB230

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 11 August 2021

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MOPAB231

Tunability Study of the Ultra-Low β* Optics at ATF2 with New Octupole Setup and Tuning Knobs

octupole, alignment, simulation, quadrupole

752

A. Pastushenko, R. Tomás García
CERN, Geneva, Switzerland
A. Faus-Golfe
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
K. Kubo, S. Kuroda, T. Naito, T. Okugi, N. Terunuma, R.J. Yang
KEK, Ibaraki, Japan

The main goal of the Accelerator Test Facility 2 (ATF2) is to demonstrate the feasibility of future linear colliders’ final focus systems. The Ultra-low β^* optics of ATF2 is designed to have the same chromaticity level as CLIC. To ease the tuning procedure, a pair of octupoles was installed in ATF2 in 2017. This paper reports the optimizations performed to the octupoles’ setup for Ultra-low β^* optics including the new alignment technique, based on the waist shift and the new tunning knobs constructed for this optics. The full tuning procedure including the static errors is simulated for this setup.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB231

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 12 August 2021

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MOPAB234

Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields

dipole, focusing, simulation, closed-orbit

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]

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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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MOPAB235

Transverse 2d Phase-Space Tomography Using Beam Position Monitor Data of Kicked Beams

emittance, electron, betatron, storage-ring

763

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

Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The time-series Beam Position Monitor (BPM) data of kicked beam is a function of lattice parameters and beam parameters including phase-space density. The decoherence model using the first-order detuning parameter has an exact solution when the beam is Gaussian. We parameterize the beam phase-space density by multiple Gaussian kernels of different weights, means, and sizes to formulate the inverse problem for 2D phase-space tomography. Numerical optimization and Bayesian inference are used to infer the beam density.

Poster MOPAB235 [1.253 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB235

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paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 01 September 2021

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MOPAB245

Theoretical Analysis of the Conditions for an Isochronous and CSR-Immune Triple-Bend Achromat with Stable Optics

emittance, dipole, radiation, synchrotron-radiation

786

C. Zhang, Y. Jiao
IHEP, Beijing, People’s Republic of China
C.-Y. Tsai
HUST, Wuhan, 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), National Key R&D Program of China (No. 2016YFA0401900)
Transport of high-brightness beams with minimum degradation of the phase space quality is pursued in modern accelerators. For the beam transfer line which commonly consists of bending magnets, it would be desirable if the transfer line can be isochronous and coherent synchrotron radiation (CSR)-immune. For multi-pass transfer line, the achromatic cell designs with stable optics would bring great convenience. In this paper, based on the transfer matrix formalism and the CSR point-kick model, we report the detailed theoretical analysis and derive the condition for a triple-bend achromat with stable optics in which the first-order longitudinal dispersion (i.e., R56) and the CSR-induced emittance growth can be eliminated. The derived condition suggests a new way of designing the bending magnet beamline that can be applied to the free-electron laser (FEL) spreader and energy recovery linac (ERL) recirculation loop.

Poster MOPAB245 [0.530 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB245

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paper received ※ 12 May 2021 paper accepted ※ 08 June 2021 issue date ※ 27 August 2021

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MOPAB258

Corrections of Non-Linear Field Errors with Asymmetric Optics in LHC and HL-LHC Insertion Regions

simulation, hadron, collider, insertion

817

J. Dilly, E.H. Maclean, R. Tomás García
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research.
Existing correction schemes to locally suppress resonance driving terms in the error-sensitive high-beta regions of the LHC and HL-LHC have operated on the assumption of symmetric beta-functions of the optics in the two rings. As this assumption can fail for a multitude of reasons, such as inherently asymmetric optics and unevenly distributed errors, an extension of this correction scheme has been developed removing the need for symmetry by operating on the two separate optics of the beams at the same time. Presented here is the impact of this novel approach on dynamic aperture as an important measure of particle stability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB258

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paper received ※ 10 May 2021 paper accepted ※ 23 July 2021 issue date ※ 16 August 2021

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MOPAB259

Corrections of Feed-Down of Non-Linear Field Errors in LHC and HL-LHC Insertion Regions

simulation, hadron, collider, insertion

821

J. Dilly, E.H. Maclean, R. Tomás García
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project, CERN and the german Federal Ministry of Education and Research.
The optics in the insertion regions of the LHC and its upgrade project the High Luminosity LHC (HL-LHC) are very sensitive to local magnetic errors, due to the extremely high beta-functions present. In collision optics, the non-zero closed orbit in the same region leads to a "feed-down" of high-order errors to lower orders, causing additional effects detrimental to beam lifetime. An extension to the proven method for correcting these errors by locally suppressing resonance driving terms has been undertaken, not only taking this feed-down into account, but also adding the possibility of utilizing it such that the powering of higher-order correctors will compensate for lower order errors. The impact of these corrections on measures of particle stability, namely dynamic aperture and amplitude detuning are presented in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB259

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paper received ※ 10 May 2021 paper accepted ※ 23 July 2021 issue date ※ 15 August 2021

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MOPAB260

Optics Corrections with LOCO on Sirius Storage Ring

quadrupole, storage-ring, coupling, MMI

825

M.B. Alves
LNLS, Campinas, Brazil

Sirius is a 4th generation 3GeV synchrotron light source at the Brazilian Center for Research in Energy and Materials (CNPEM). In this work, we report the results of linear optics and coupling corrections during the commissioning of Sirius storage ring, using the Linear Optics from Closed Orbits (LOCO) algorithm. Beam-based measurements were performed to verify independently the impact of corrections on storage ring parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB260

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 30 August 2021

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MOPAB269

Three Approaches for Complete Measurement of the Transverse Beam Optics Along the Fermilab Muon Campus Extraction Line

quadrupole, extraction, dipole, real-time

854

B.D. Simons, M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA
D. Stratakis, M.J. Syphers
Fermilab, Batavia, Illinois, USA

Funding: This work was supported through grant DE-SC0020379 with the United States Department of Energy.
Traditionally, the process of measuring the optical parameters of a beamline has employed the use of one of two standard methods, namely the three-screen method or a quadrupole magnet scan. Both require either an area of zero dispersion to perform the measurements or knowledge of the dispersion function and momentum spread beforehand in order to provide accurate results. There is however a third method that can be used to measure the standard optical parameters, the beam parameters, the dispersion function, and the momentum spread simultaneously. This method, aptly named the six-screen method, is an extension of the more standard three-screen method. Utilizing the simulation environment of G4beamline, we simulated the 8 GeV proton beam in the M4 beamline and measured the optical and beam parameters using the two standard approaches. Those results were then used as a reference to check the viability of employing the less standard six-screen method in the M4 line. If shown to be a viable option, the six-screen method could be used to retrieve the dispersion function and momentum spread of the beam without needing to change the energy of the beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB269

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paper received ※ 20 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021

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MOPAB417

Preliminary Study of a Large Energy Acceptance FFA Beam Delivery System for Particle Therapy

proton, focusing, superconducting-magnet, radiation

1256

J.S.L. Yap, E.R. Higgins, S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

The availability and use of ion beams for radiotherapy has grown significantly, led by technological developments to exploit the dosimetric advantages offered by charged particles. The benefits of particle therapy (PT) are well identified however its utilisation is still limited by high facility costs and technological challenges. A possibility to address both of these can be considered by improvements to the beam delivery system (BDS). Existing beamlines and gantries transport beams with a momentum range of ±1% and consequently, adjustments in depth or beam energy require all the magnetic fields to be changed. The speed to switch energies is a limiting constraint of the BDS and a determinant of the overall treatment time. A novel concept using fixed field alternating gradient (FFA) optics enables a large energy acceptance (LEA) as beams of varying energies can traverse the beamline at multiple physical positions given the same magnetic field. This presents the potential to provide faster, higher quality treatments at lower costs, with the capability to deliver advanced PT techniques such as multi-ion therapy. We explore the applicability and benefits of a LEA BDS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB417

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paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 15 August 2021

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TUPAB001

DAΦNE Commissioning for SIDDHARTA-2 Experiment

luminosity, collider, feedback, positron

1322

C. Milardi, D. Alesini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, A. D’Uffizi, A. De Santis, C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, G. Franzini, A. Gallo, S. Incremona, A. Michelotti, L. Pellegrino, L. Piersanti, R. Ricci, U. Rotundo, L. Sabbatini, A. Stecchi, A. Stella, A. Vannozzi, M. Zobov
INFN/LNF, Frascati, Italy
J. Chavanne, G. Le Bec, P. Raimondi
ESRF, Grenoble, France

DAΦNE, the Frascati lepton collider, has completed the preparatory phase in order to deliver luminosity to the SIDDHARTA-2 detector. DAΦNE colliding rings rely on a new interaction region, which implements the well-established Crab-Waist collision scheme, and includes a low-beta section equipped with newly designed permanent magnet quadrupoles, and vacuum components. Diagnostics tools have been improved, especially the ones used to keep under control the beam-beam interaction. The horizontal feedback in the positron ring has been potentiated in order to achieve a higher positron current. Luminosity diagnostics have been also updated so to be compatible with the new detector design. The commissioning was initially focused on recovering the optimal dynamical vacuum conditions, outlining alignment errors, and optimizing ring optics. For this reason, a detuned optics, featured by relaxed low-b condition at the interaction point and Crab-Waist Sestupoles off, has been applied. In a second stage a low-b optics has been implemented to test collisions with a preliminary setup of the experiment detector. Machine preparation and the first luminosity results are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB001

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 August 2021

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TUPAB004

Comparison of Accelerator Codes for Simulation of Lepton Colliders

radiation, lattice, emittance, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB004

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paper received ※ 16 May 2021 paper accepted ※ 15 June 2021 issue date ※ 26 August 2021

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TUPAB006

The Impact of Beam Position Monitor Tilts on Coupling Measurements

coupling, resonance, simulation, quadrupole

1342

L. van Riesen-Haupt, R. Tomás García
CERN, Meyrin, Switzerland

The measurement and correction of coupling resonance driving terms is a key tool for improving the performance of synchrotrons. These terms are measured by exciting the beam and observing the subsequent motion in the horizontal and vertical planes through beam position monitors. This paper outlines the impact of tilt errors in these monitors to the distortion of the amount of coupling measured between the planes and how the computation of the resonance driving terms is affected by these tilts. It also attempts to use these results for mimicking tilt errors in simulations and discusses how discrepancies in measured resonance driving terms could be used to estimate the tilt errors that cause them.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB006

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 12 August 2021

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TUPAB007

A Correction Scheme for the Magnet Imperfection on the CEPC Collider Ring

lattice, quadrupole, emittance, alignment

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 TUPAB007 [1.075 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB007

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paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021

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TUPAB009

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

closed-orbit, 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

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

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TUPAB010

Impact of Bunch Current on Optics Measurements in SuperKEKB

damping, impedance, quadrupole, radiation

1356

J. Keintzel, R. Tomás García, F. Zimmermann
CERN, Geneva, Switzerland
T. Ishibashi, H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, S. Terui, M. Tobiyama, R.J. Yang, D. Zhou
KEK, Ibaraki, Japan

SuperKEKB has recently achieved the world record instantaneous luminosity of 2.8 × 10³⁴ \si{cm^-2s^-1} and aims at reaching a target luminosity of about 6 × 10³⁵ \si{cm^-2s^-1}. To accomplish this goal it is planned to increase beam currents up to §I{3.6}{A} and §I{2.6}{A} for the positron and the electron ring, respectively. Increasing the beam currents and, in particular, the number of leptons per bunch, can impact the optics parameters obtained by turn-by-turn measurements, such as the betatron tune or phase advance. Optics measurements performed at various bunch currents can give first indications of possible intensity dependent effects. In this paper, the effect of varying bunch current on optics measurements at SuperKEKB is explored.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB010

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 30 August 2021

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TUPAB011

Momentum Compaction Factor Measurements in the Large Hadron Collider

quadrupole, synchrotron, collider, hadron

1360

J. Keintzel, L. Malina, R. Tomás García
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) at CERN and its planned luminosity upgrade, the High Luminosity LHC (HL-LHC) demand well-controlled on- and off-momentum optics. Optics measurements are performed by analysing Turn-by-Turn (TbT) data of excited beams. Different techniques to measure the momentum compaction factor from these data are explored, taking into account the possibility to combine them with RF-voltage scans in future experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB011

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paper received ※ 18 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021

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TUPAB040

Design Concept for the Second Interaction Region for Electron-Ion Collider

electron, detector, proton, dipole

1435

B.R. Gamage, V. Burkert, R. Ent, Y. Furletova, D.W. Higinbotham, A. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, D. Romanov, T. Satogata, A. Seryi, A.V. Sy, C. Weiss, M. Wiseman, W. Wittmer, Y. Zhang
JLab, Newport News, Virginia, USA
E.C. Aschenauer, J.S. Berg, A. Jentsch, A. Kiselev, C. Montag, R.B. Palmer, B. Parker, V. Ptitsyn, F.J. Willeke, H. Witte
BNL, Upton, New York, USA
C. Hyde
ODU, Norfolk, Virginia, USA
P. Nadel-Turonski
SBU, Stony Brook, New York, USA

Funding: Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 and Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The possibility of two interaction regions (IRs) is a design requirement for Electron-Ion Collider (EIC). There is also a significant interest from the nuclear physics community to have a 2nd IR with measurement capabilities complementary to those of the 1st IR. While the 2nd IR will be in operation over the entire energy range of ~20GeV to ~140GeV center of mass (CM). The 2nd IR can also provide an acceptance coverage complementary to that of the 1st. In this paper, we present a brief overview and the current progress of the 2nd IR design in terms of the parameters, magnet layout, and beam dynamics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB040

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paper received ※ 24 May 2021 paper accepted ※ 31 August 2021 issue date ※ 30 August 2021

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TUPAB048

HMBA Optics Correction Experience at ESRF

lattice, 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.

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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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TUPAB049

USSR HMBA Storage Ring Lattice Options

injection, emittance, lattice, SRF

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB049

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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, lattice, injection

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB050

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paper received ※ 12 May 2021 paper accepted ※ 11 June 2021 issue date ※ 24 August 2021

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TUPAB059

Measurement of the Advanced Photon Source Lifetime at Different Level of Beta-Beating

quadrupole, betatron, storage-ring, simulation

1496

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.
Linear optics correction of a particle accelerator may not be perfect due to the existence of different errors sources in response matrix measurements and optics correction process. Previous numerical simulation study has shown that the single particle beam dynamics performance may be highly correlated with the level of residual beta-beating. In this paper, the machine study results on beam lifetime of the APS storage ring is presented. The experiment is performed at different level of predefined beta-beating with negligible betatron tunes variations. As expected, the measured beam lifetime has an inverse correlation with the level of beta-beating.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB059

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 16 August 2021

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TUPAB106

Simulation Calculations of Compact THz Facility at IUAC, New Delhi

undulator, radiation, simulation, electron

1633

J. Karmakar, S. Ghosh
IUAC, New Delhi, India

A compact THz radiation source based on the principle of pre-bunched Free Electron Laser is at the commissioning stage at Inter University Accelerator Centre (IUAC), New Delhi. The facility will generate low emittance train of electron micro-bunches (2, 4, 8 or 16 numbers) from a RF photo-cathode gun in the energy range of 4 to 8 MeV and inject into a compact undulator to generate coherent THz radiation in the frequency range of ~0.18 to 3.0 THz. To optimize the intensity at a given frequency, the beam bunching factor and the betatron oscillation amplitude in the non-wiggling plane of the electronμbunches inside the undulator has been maximized and minimized respectively. The paper presents the optimized beam optics simulation results for two frequencies viz 0.5 and 2 THz. The on-axis radiation spectral intensity computed by in-house developed code using the trajectory data of the beam optics simulation is also presented for the two frequencies.

Poster TUPAB106 [1.208 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB106

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paper received ※ 18 May 2021 paper accepted ※ 31 August 2021 issue date ※ 12 August 2021

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TUPAB117

Eigenmode Decomposition for Free-Electron Lasers Using Bayesian Analysis

laser, FEL, simulation, distributed

1666

P. Liu, W. Li, Y.K. Wu, J. Yan
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
Laser beams from an optical cavity, such as free-electron laser (FEL) resonators, are typically a mixture of the cavity’s eigenmodes, such as the Hermite-Gaussian (HG) modes or Laguerre-Gaussian (LG) modes. Robust evaluation of the eigenmode spectrum of a multimode laser beam has various applications in laser development, research, and utilization. In this work, a general eigenmode decomposition method for a multimode laser beam has been developed based on Bayesian analysis. This problem is transformed into a linear system and then solved using a Gaussian probabilistic model. Using Bayesian analysis, prior knowledge about the mode content is further incorporated into the solution to improve the results for laser beams contaminated with complex disturbances. The decomposition of the beam image from the incoherent intensity addition of HG modes is discussed with different types of noise or disturbances. The simulation results have been used to show the robustness of this method. This method can be straightforwardly extended into other cases such as the wavefront decomposition into the coherent superposition of HG and LG modes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB117

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 01 September 2021

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TUPAB171

Linear Transfer Matrix of a Half Solenoid

solenoid, emittance, coupling, ion-source

1789

P.F. Ma, X. Guan, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China

Solenoid magnets can provide strong transverse focusing to electrons and ions with relatively small energies. For the ECR heavy-ion source, the ions are extracted at the central area of the solenoid, the beam is coupled at the exit of the source. The coupling caused by the solenoids can lead to the growth of projected transverse emittance, which has been widely studied with great interest. It is important to study the transfer matrix of a half solenoid to study the beam optics in an ECR souce, thus the property of the beam can be given. Based on the transfer matrix calculation, the summary of the linear transfer matrix of a half solenoid can be given. The beam optics in a half solenoid is studied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB171

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paper received ※ 18 May 2021 paper accepted ※ 28 June 2021 issue date ※ 29 August 2021

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TUPAB195

Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning

MMI, controls, neutron, resonance

1865

Y.W. An, Y. Li, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China
M.T. Li
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.

Poster TUPAB195 [2.279 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195

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paper received ※ 13 May 2021 paper accepted ※ 17 June 2021 issue date ※ 01 September 2021

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TUPAB208

FETS-FFA Ring Study

lattice, injection, 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.

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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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TUPAB217

Effect of Undulators on Transverse Resonant Island Orbits

undulator, operation, diagnostics, dipole

1927

E.C.M. Rial, J. Bahrdt, P. Goslawski, A. Meseck, M. Ries, M. Scheer
HZB, Berlin, Germany

For one week in October 2020, BESSY II offered a Two Orbit mode to users for the first time*. In this Two Orbit mode, the existence of transverse resonant island buckets** are exploited to store a second beam in the storage ring as an ’island orbit’, away from the primary beam axis. This mode was offered with free range of motion of the 12 out of vacuum undulators installed at the BESSY II ring. Diagnostics of the island orbit were limited to a single camera monitoring bending magnet radiation from a single dipole. A significant motion of the island orbit was observed on this diagnostic and correlated with undulator motion. This observation is reported, and simulations presented to demonstrate how this motion could arise. Correction schemes are suggested and discussed.
*Two Orbit - a report on the first scheduled week of TRIBs user operation at BESSY II, M. Ries et al, these proceedings
**Proc. IPAC 2016, Busan, S Korea, paper THPMR017, p. 3427

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB217

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 22 August 2021

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TUPAB219

Equilibrium and Nonlinear Beam Dynamics Parameters From Sirius Turn-by-Turn BPM Data

experiment, emittance, betatron, factory

1935

X.R. Resende, M.B. Alves, L. Liu, F.H. de Sá
LNLS, Campinas, Brazil

A considerable amount of beam information is conveyed by Turn-by-Turn (TbT) data of Beam Position Monitors (BPM). In this work such data sets are analyzed for Sirius, the Brazilian 4th Generation 3GeV synchrotron light source. In particular, equilibrium and non-linear beam dynamics parameters determining decoherence patterns in TbT position data are estimated and compared with corresponding values of the nominal storage ring model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB219

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paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 15 August 2021

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TUPAB224

Non-Linear Variation of the Beta-Beating Measured From Amplitude

octupole, simulation, resonance, target

1949

T. Pugnat, B. Dalena
CEA-IRFU, Gif-sur-Yvette, France
A. Franchi
ESRF, Grenoble, France
R. Tomás García
CERN, Geneva, Switzerland

Accelerator physics needs advanced modeling and simulation techniques, for beam stability studies but also for the measurement of beam parameters like the Twiss parameters. A deeper understanding of magnetic field non-linearities effects will greatly help in the improvement of future circular collider design, performance, and diagnostics. This paper studies the variation of the \beta-beating with the action of the particle generated by non-linear Resonance Driving Terms, both from a theoretical and an experimental point of view.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB224

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 21 August 2021

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TUPAB228

IOTA Run 2 Beam Dynamics Studies in Nonlinear Integrable Systems

octupole, experiment, lattice, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB228

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paper received ※ 31 May 2021 paper accepted ※ 23 June 2021 issue date ※ 10 August 2021

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TUPAB236

Progress on the Electron Gun Design for a McMillan Electron Lens in the Fermilab Integrable Optics Test Accelerator (IOTA)

electron, gun, cathode, simulation

1988

B.L. Cathey, G. Stancari
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.
This paper covers the progress made so far in designing the first McMillan electron lens for the Fermilab IOTA ring. The novel design allows for an increase in tune spread without limiting the dynamic aperture due to its integrability. Shown are simulations for an electron gun design to generate the specific required current density distribution for the nonlinear integrable system in IOTA.

Poster TUPAB236 [5.391 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB236

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021

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TUPAB311

Nonlinear Correctors Tuning for the Collector Ring Isochronous Mode

sextupole, betatron, controls, proton

2218

M.A. Lyalin, I. Koop, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia
I. Koop, M.A. Lyalin, D.B. Shwartz
NSU, Novosibirsk, Russia

One of the operating modes for the Collector Ring (CR) under construction in Darmstadt is the isochronous mode, in which the captured ions circulate with an equal period regardless of their momentum. The measurement of the orbital period T by the time-of-flight sensors makes it possible to precisely determine the mass to the charge ratio of the ion under study. For this, the change of the circulation period dT should not exceed 1·10^-6 for dT/T in the entire momentum acceptance of the 0.62%. Modeling in the Strategic Accelerator Design code showed that without nonlinear effects compensation, the orbital period variation is 1·10^-5. In this work, the parameters of nonlinear correctors, which are sextupoles and octupoles in CR, are determined, necessary for the isochronous mode implementation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB311

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paper received ※ 29 May 2021 paper accepted ※ 16 June 2021 issue date ※ 14 August 2021

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TUPAB361

Study and Design of a Fast Switching Magnet for the MYRRHA Project

dipole, linac, proton, beam-transport

2356

E. Froidefond, F. Bouly, P.-O. Dumont
LPSC, Grenoble Cedex, France
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: Work supported by SCK•CEN, CNRS/IN2P3, Univ. Grenoble Alpes.
The MYRRHA project aims at building an Accelerator Driven System demonstrator, which consists of two injectors and a superconducting linac. The proton beam from the first injector accelerated up to 17 MeV goes to the linac (600 MeV) through a Medium Energy Beam Transfer line (MEBT). Whereas in the meantime, the beam from the second injector is sent to a beam dump. In case of failure in the first injector, the beam of the awaiting injector is sent to the linac. A switching magnet located at the junction of the two injection lines performs this beam switch in less than 1.5 seconds. A magnetic design and a mechanical structure of this magnet proposed to the MYRRHA project are presented.
*emmanuel.froidefond@lpsc.in2p3.fr

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB361

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 23 August 2021

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TUPAB407

A Novel Beam Optics Concept to Maximize the Transmission Through Cyclotron-based Proton Therapy Gantries

proton, emittance, quadrupole, simulation

2477

V. Maradia, A.C. Giovannelli, A.L. Lomax, D. Meer, S. Psoroulas, J.M. Schippers, D.C. Weber
PSI, Villigen PSI, Switzerland
V. Maradia
ETH, Zurich, Switzerland
D.C. Weber
University of Zurich, University Hospital, Zurich, Switzerland
D.C. Weber
KRO, Bern, Switzerland

Funding: This work is funded by a PSI inter-departmental funding initiative (CROSS).
Most of the conventional beam optics of cyclotron-based proton gantries were designed to provide point-to-point focus in both planes with an imaging factor between 1 and 2 from the entrance of the gantry to the patient. This means that a small beam size at the gantry entrance is required to achieve the required small beam size at the patient. Due to the typically used beam emittance, this in turn results in large beam divergence at the gantry entrance, increasing the possibility of beam losses along the gantry as the beam envelope gets close to the apertures. To maximize transmission through the gantry, we propose a novel beam optics concept using 3:1 imaging. It reduces the beam divergence at the gantry entrance by factor 3 while still achieving a small beam size at the patient. The beam envelope is better controlled and keeps clear of the apertures compared to the 1:1 or 1:2 imaging beam envelope. For PSI Gantry 2, the novel 3:1 imaging beam optics increase the proton beam transmission for lower energies by 40% compare to 1:1 imaging beam optics. The usage of small imaging factors can help to maximize transmission for different gantry lattices, thus reducing treatment times.

Poster TUPAB407 [1.347 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB407

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paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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WEPAB001

Accelerator Challenges of the LHeC Project

electron, emittance, linac, proton

2570

B.J. Holzer, K.D.J. André, O.S. Brüning
CERN, Geneva, Switzerland
S.A. Bogacz
JLab, Newport News, Virginia, USA
M. Klein
The University of Liverpool, Liverpool, United Kingdom

The LHeC project studies the design of a future electron-proton collider at CERN that will run in parallel to the standard LHC operation. For this purpose, the existing LHC storage ring will be combined with an Energy Recovery Linac (ERL), to accelerate electrons up to kinetic energy of 50 GeV. This concept - also applicable to the FCC-eh collider and studied at the PERLE project as prototype version - allows a peak luminosity of 10³⁴ cm^-2 s^-1. A sophisticated design of the RF structures, linacs, arcs, and interaction region is required. The electrons are accelerated and, after the interaction point, their energy is recovered through the same RF structures. While this energy recovery concept is a very promising approach, severe challenges are set by the layout of the interaction region, the beam separation concept and the design of the linac and arc lattice for the highest possible momentum acceptance. Emittance control and beam-beam effect of both, electron and proton beams, have been studied in front-to-end simulations and will be presented. We summarise the design principles of the ERL, the optimization of the arc lattice, and the main parameters of the project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB001

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paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 21 August 2021

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WEPAB026

Optics Measurements and Correction Plans for the HL-LHC

coupling, luminosity, dynamic-aperture, dipole

2656

T.H.B. Persson, X. Buffat, F.S. Carlier, R. De Maria, J. Dilly, E. Fol, D. Gamba, H. Garcia Morales, A. García-Tabarés Valdivieso, M. Giovannozzi, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, P.K. Skowroński, F. Soubelet, R. Tomás García, F.F. Van der Veken, A. Wegscheider, D.W. Wolf, L. van Riesen-Haupt
CERN, Geneva, Switzerland
J.M. Coello de Portugal
PSI, Villigen PSI, Switzerland

The High Luminosity LHC (HL-LHC) will require stringent optics correction to operate safely and deliver the design luminosity to the experiments. In order to achieve this, several new methods for optics correction have been developed. In this article, we outline some of these methods and we describe the envisioned strategy of how to use them in order to reach the challenging requirements of the HL-LHC physics program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB026

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paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 30 August 2021

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WEPAB027

Optics Correction Strategy for Run 3 of the LHC

coupling, dipole, MMI, quadrupole

2660

T.H.B. Persson, R. De Maria, J. Dilly, E. Fol, H. Garcia Morales, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, F. Soubelet, R. Tomás García, A. Wegscheider, D.W. Wolf, L. van Riesen-Haupt
CERN, Geneva, Switzerland
J.F. Cardona
UNAL, Bogota D.C, Colombia

The Run 3 of the LHC will continue to provide new challenges for optics corrections. In order to succeed and go beyond what was achieved previously, several new methods to measure and correct the optics have been developed. In this article we describe these methods and outline the plans for the optics commissioning in 2022.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB027

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paper received ※ 17 May 2021 paper accepted ※ 12 July 2021 issue date ※ 11 August 2021

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WEPAB074

A Distributed Sextupoles Lattice for the ALBA Low Emittance Upgrade

lattice, emittance, sextupole, injection

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

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 22 August 2021

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WEPAB079

Optics Studies on the Operation of a New Wiggler and Bunch Shortening at the DELTA Storage Ring

wiggler, cavity, storage-ring, operation

2772

B. Büsing, P. Hartmann, A. Held, S. Khan, C. Mai, D. Schirmer, G. Schmidt
DELTA, Dortmund, Germany

Funding: Work supported by Deutsche Forschungsgemeinschaft via project INST 212/330-1 AOBJ: 619186
The 1.5-GeV electron storage ring DELTA is a synchrotron light source operated by the TU Dortmund University. Radiation from hard X-rays to the THz regime is provided by dipole magnets and insertion devices like undulators and wigglers. To provide even shorter wavelengths, a new 22-pole superconducting 7-T wiggler has been installed. The edge focusing of the wiggler has a large impact on the linear optics of the storage ring. Measurements regarding its influence and simulations were performed. In addition, a second radiofrequency (RF) cavity has been installed to compensate the increased energy loss per turn due to the new wiggler. As a consequence of the higher RF power, the electron bunches are shorter compared to the old setup with only one cavity. In view of reducing the bunch length even more, studies of the storage ring optics with reduced momentum compaction factor were performed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB079

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paper received ※ 19 May 2021 paper accepted ※ 24 June 2021 issue date ※ 01 September 2021

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WEPAB088

Transverse Beam Emittance Measurement by Undulator Radiation Power Noise

radiation, emittance, undulator, synchrotron

2794

I. Lobach
University of Chicago, Chicago, Illinois, USA
A. Halavanau, Z. Huang
SLAC, Menlo Park, California, USA
K. Kim
ANL, Lemont, Illinois, USA
V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA

Generally, turn-to-turn power fluctuations of incoherent spontaneous synchrotron radiation in a storage ring depend on the 6D phase-space distribution of the electron bunch. In some cases, if only one parameter of the distribution is unknown, this parameter can be determined from the measured magnitude of these power fluctuations. In this contribution, we report the results of our experiment at the Integrable Optics Test Accelerator (IOTA) storage ring, where we carried out an absolute measurement (no free parameters or calibration) of a small vertical emittance (5–15 nm rms) of a flat beam by this new method, under conditions, when the small vertical emittance is unresolvable by a conventional synchrotron light beam size monitor.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB088

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paper received ※ 17 May 2021 paper accepted ※ 24 June 2021 issue date ※ 12 August 2021

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WEPAB180

Design and Beam Dynamics Studies of a Novel Compact Recoil Separator Ring for Nuclear Research with Radioactive Beams

ISOL, dipole, quadrupole, operation

3031

J. Resta-López
UVEG, Burjasot (Valencia), Spain
A.P. Foussat, G. Kirby
CERN, Geneva, Switzerland
I. Martel
University of Huelva, Huelva, Spain
V. Rodin
The University of Liverpool, Liverpool, United Kingdom
V. Rodin
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was supported by the Generalitat Valenciana under grant agreement CIDEGENT/2019/058
The recent development of radioactive beam facilities has significantly expanded the capabilities for investigating the structure of the atomic nucleus and the nuclear interaction. For instance, the HIE-ISOLDE facility at CERN delivers presently the largest range of low-energy radioactive beam available worldwide. This energy range is ideal for the study of nuclear structure, low-energy dynamics and astrophysics by using nucleon transfer, Coulomb excitation and deep inelastic reactions. All these studies require an efficient and high-resolution recoil separator for the clear identification of medium and large mass reaction fragments. To meet these needs, we propose a versatile recoil separator for radioisotopes based on a compact storage ring, the Isolde Superconducting Recoil Separator (ISRS) formed of superconducting combined-function nested magnets with both, bending and focusing/defocusing functions. The ISRS is designed to operate in high momentum acceptance and isochronous modes. In this paper, we present the optics design and detailed beam dynamics studies for the performance characterisation.

Poster WEPAB180 [3.619 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB180

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 31 August 2021

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WEPAB185

Target Bypass Beam Optics for Future High Intensity Fixed Target Experiments in the CERN North Area

target, experiment, proton, quadrupole

3046

G.L. D’Alessandro, D. Banerjee, J. Bernhard, M. Brugger, N. Doble, L. Gatignon, A. Gerbershagen, B. Rae, F.M. Velotti
CERN, Meyrin, Switzerland
S.M. Gibson
JAI, Egham, Surrey, United Kingdom

Several of the proposed experiments for operation at the K12 beam line would profit from significant beam intensity increase. Among those, there is the KLEVER experiment that would require an intensity of 2x10¹³ protons per 4.8 s long spill. The main goal of the experiment is to measure BR(KL->pi0 nu nu) to test the Standard Model structure by itself, and in combination with results from NA62 for BR(K±>pi+ nu nu). NA62 could also profit from higher intensities, and could be run in a new configuration called NA62HI(gher intensity). In the current configuration the beam is transported from the SPS to the TT24 beamline. This beamline leads to the T4 target that attenuates the beam for P42. After T4 the beam is directed into the P42 beamline before impinging on the T10 target and creating the particles necessary for the experiment. Those are finally transported to the detector via K12. This paper presents the idea of partially bypassing T4 and changing the P42 beamline configuration in order to have a sufficiently small beam size at the T10 target for both KLEVER and NA62-HI. Optics studies are developed in MADX and the AppLE.py, software developed at CERN.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB185

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paper received ※ 17 May 2021 paper accepted ※ 01 July 2021 issue date ※ 27 August 2021

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WEPAB279

On Wire-Corrector Optimization in the HL-LHC and the Appearance of Special Aspect Ratios

target, coupling, insertion, resonance

3297

D. Kaltchev
TRIUMF, Vancouver, Canada

For the two high-luminosity insertions of the Large Hadron Collider (HL-LHC) current bearing wire correctors are intended to mitigate the detrimental effect of long-range beam-beam interactions. With respect to finding the optimum longitudinal location of the wire, two special locations corresponding to the special values 2 and 1/2 of the beta-function aspect ratio have been previously shown to provide simultaneous cancellation of multiple two-dimensional Resonance Driving Terms. This paper attempts to explain the appearance of such special aspect ratios.

Poster WEPAB279 [1.238 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB279

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paper received ※ 14 May 2021 paper accepted ※ 19 July 2021 issue date ※ 13 August 2021

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WEPAB280

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

resonance, closed-orbit, lattice, luminosity

3301

D. Kaltchev
TRIUMF, Vancouver, Canada

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

Poster WEPAB280 [1.235 MB]

DOI •

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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WEPAB302

COSY Machine-Model Optimization

dipole, operation, simulation, betatron

3375

I. Bekman, J.H. Hetzel
FZJ, Jülich, Germany

Funding: Helmholtz Association
Successful operation of a particle accelerator requires accompanying model calculations. The model helps in understanding the machine and predicts the impact of a change in the settings (e.g. current of magnetic elements). For the COoler SYnchrotron (COSY) at Research Center Jülich the accelerator simulation software MAD-X is used to model the machine. The model parameters are steadily being improved based on various manual adjustments and analytical studies, however are hardly optimized all at once. This can be improved with machine learning methods. The model is used to predict measurable quantities, like Orbit Response Matrix (ORM) or betatron tunes. Several observables for different particle energies have been measured recently and the corresponding machine settings are available. We describe the effort to improve the agreement between measured and calculated ORMs and hence improve the agreement between model and (real) machine and report on the optimization using a multivariate algorithm (e.g. genetic algorithm). This facilitates the setup of COSY and will allow to perform high precision experiments e.g. a measurement of an electric dipole moment of deuterons at COSY.

Poster WEPAB302 [1.905 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB302

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paper received ※ 14 May 2021 paper accepted ※ 28 July 2021 issue date ※ 20 August 2021

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WEPAB383

An Evolutionary Algorithm Approach to Multi-Pass ERL Optics Design

linac, quadrupole, focusing, simulation

3610

I. Neththikumara, T. Satogata
ODU, Norfolk, Virginia, USA
R.M. Bodenstein, S.A. Bogacz, T. Satogata
JLab, Newport News, Virginia, USA
A. Vandenhoeke
ULB, Bruxelles, Belgium

Funding: This material is based upon work supported by the U.S. Department of Energy under contract DE-AC05-06OR23177.
An Energy Recovery Experiment at CEBAF (ER@CEBAF) is aimed at demonstrating high energy, low current, multi-pass energy recovery at the existing 12 GeV CEBAF accelerator. The beam break-up instability, limiting the maximum beam current, can be controlled through minimizing beta functions for the lowest energy pass, which gives a preference to strongly focusing optics, e.g. a semi-periodic FODO lattice. On the other hand, one needs to limit beta function excursions, caused by under focusing, at the higher energy passes, which in turn favors weakly focusing linac optics. Balancing both effects is the main objective of proposed multi-pass linac optics optimization. Here, we discuss an optics design process for ER@CEBAF transverse optics using a genetic algorithm.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB383

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 15 August 2021

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WEPAB399

Applications of the Local Observable in Future Optics Measurements in HL-LHC and PETRA III

lattice, 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

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paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 12 August 2021

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WEPAB400

Forced Coupling Resonance Driving Terms

coupling, dipole, resonance, simulation

3646

A. Wegscheider, R. Tomás García
CERN, Meyrin, Switzerland

At the LHC, coupling is routinely measured using forced oscillations of the beam through excitation with an AC-dipole. The driving of the particle motion has an impact on the measurement of resonance driving terms. Recent findings suggest that the current models describing the forced motion are neglecting a local effect of the AC-dipole, creating a jump of the amplitude of the resonance driving terms. This work presents a study of the improvement of coupling measurements for typical LHC optics as well as its upgrade project HL-LHC, by using the new model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB400

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 20 August 2021

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THXA07

Driven 3D Beam Oscillations for Optics Measurements in Synchrotrons

dipole, synchrotron, betatron, emittance

3704

L. Malina, J.M. Coello de Portugal, H. Timko, R. Tomás García
CERN, Geneva, Switzerland

Optics measurements in storage rings employ turn-by-turn data of transversely excited beams. Traditionally, to measure chromatic properties, the relative momentum is changed step-wise, which is time-consuming and almost impractical during the energy ramp. We present an optics measurement method based on adiabatic simultaneous 3-dimensional beam excitation, which is more time-efficient and well fitted for the energy ramp. This method was successfully demonstrated in the LHC utilising AC-dipoles in combination either with a slow RF-frequency modulation or a driven RF-phase modulation close to the synchrotron frequency. Faster longitudinal oscillations improve the accuracy of optics parameters inferred from the synchro-betatron sidebands. This paper reports on the experimental demonstration of optics measurements based on 3D driven beam excitations and the plans for LHC Run 3.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA07

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 11 August 2021

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THXB05

Inverse Orbit Response Matrix Measurements: A Possible On-Line Tool for Optics Control in Storage Rings

quadrupole, operation, storage-ring, insertion

3724

Z. Martí, G. Benedetti, U. Iriso, E. Morales
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

We propose a novel technique to measure the linear optics in storage rings based on the acquisition of the inverse orbit response matrix (iORM). The iORM consists in the orbit correctors magnets (OCM) strength changes needed to produce a local orbit variation in each beam position monitor (BPM). This measurement can be implemented by introducing sequentially small changes in the BPM offsets and logging the OCM setting variations when the orbit correction is running. Very high precision and accuracy in the OCM set-points is required which poses a considerable challenge. Since the orbit feedback (FOFB) is kept running, the iORM could potentially be acquired in parallel to users storage ring operation. Since the iORM is very linear and local, optics perturbations could be easily diagnosed online. This paper introduces the iORM measurement concept and presents the progress of these studies at ALBA, where the implementation of this technique is limited by hysteresis effects in the OCM and the FOFB performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXB05

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paper received ※ 19 May 2021 paper accepted ※ 29 July 2021 issue date ※ 12 August 2021

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THPAB011

Monte Carlo Driven MDI Optimization at a Muon Collider

detector, simulation, collider, interaction-region

3769

C. Curatolo, D. Lucchesi
Univ. degli Studi di Padova, Padova, Italy
F. Collamati
INFN-Roma1, Rome, Italy
C. Curatolo, D. Lucchesi
INFN- Sez. di Padova, Padova, Italy
A. Mereghetti
CERN, Meyrin, Switzerland
A. Mereghetti
CNAO Foundation, Pavia, Italy
N.V. Mokhov
Fermilab, Batavia, Illinois, USA
M.A. Palmer
BNL, Upton, New York, USA
P.R. Sala
INFN-Milano, Milano, Italy

A Muon Collider represents a very interesting possibility for a future machine to explore the energy frontier in particle physics. However, to reach the needed luminosity, beam intensities of the order of 10⁹–10¹² muons per bunch are needed. In this context, the Beam-Induced Background must be taken into account for its effects on magnets and detector. Several mitigation strategies can however be conceived. In this view, it is of crucial importance to develop a flexible tool that allows to easily reconstruct the machine geometry in a Monte Carlo code, allowing to simulate in detail the interaction of muon decay products in the machine, while being able to change the machine optics itself to find the best configuration. In this contribution, a possible approach to such a purpose is presented, based on FLUKA for the Monte Carlo simulation and on LineBuilder for the geometry reconstruction. Results based on the 1.5 TeV machine optics developed by the MAP collaboration are discussed, as well as a first approach to possible mitigation strategies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB011

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paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 01 September 2021

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THPAB055

Reconstruction of Linear Optics Observables Using Supervised Learning

simulation, target, operation, MMI

3875

E. Fol, H. Garcia, R. Tomás García
CERN, Meyrin, Switzerland

In the LHC, most of the optical functions can be obtained from turn-by-turn beam centroid data. However, the measurement of such observables as β^* and the dispersion function require special dedicated techniques and additional operational time. In this work, we propose an alternative approach to estimate these observables using supervised machine learning, in case the dedicated measurements are not available but turn-by-turn data are. The performance of developed estimators is demonstrated on LHC simulations. Comparison to traditional techniques for the computation of beta-function will be also provided.

Poster THPAB055 [0.713 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB055

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 15 August 2021

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THPAB068

Denoising of Optics Measurements Using Autoencoder Neural Networks

network, simulation, MMI, controls

3915

E. Fol, R. Tomás García
CERN, Meyrin, Switzerland

Noise artefacts can appear in optics measurements data due to instrumentation imperfections or uncertainties in the applied analysis methods. A special type of semi-supervised neural networks, autoencoders, are widely applied to denoising tasks in image and signal processing as well as to generative modeling. Recently, an autoencoder-based approach for denoising and reconstruction of missing data has been developed to improve the quality of phase measurements obtained from harmonic analysis of LHC turn-by-turn data. We present the results achieved on simulations demonstrating the potential of the new method and discuss the effect of the noise in light of optics corrections computed from the cleaned data.

Poster THPAB068 [0.881 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB068

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paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 02 September 2021

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THPAB089

Lattice Design for a Future Plan of UVSOR Synchrotron

emittance, dynamic-aperture, lattice, 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 THPAB089 [1.592 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB089

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 16 August 2021

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THPAB104

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

lattice, closed-orbit, alignment, quadrupole

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

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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, lattice, 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB124

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 28 August 2021

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THPAB130

Design of a Very Low Energy Beamline for NA61/SHINE

target, experiment, hadron, simulation

4017

C.A. Mussolini, N. Charitonidis
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
Y. Nagai
Colorado University at Boulder, Boulder, Colorado, USA
Y. Nagai
ELTE, Budapest, Hungary
E.D. Zimmerman
CIPS, Boulder, Colorado, USA

A new, low-energy beamline branch is currently under consideration for the H₂ beamline at the CERN North Area. This new branch would extend the capabilities of the current infrastructure enabling the study of particles in the very low, 1-13 GeV/c, momentum range. The design of this new beamline involves various stages. Firstly, a study of the secondary targets to maximise the yield of secondary hadrons. Secondly, the development of high acceptance transverse optics with high momentum resolution on the order of a few %. Finally, we discuss the first considerations on instrumentation to enable particle identification and background rejection. The first experiment to profit from this new line could be NA61/SHINE, but other possible future fixed target experiments or test-beams installed in the downstream zones could also use the low-energy particles provided. The aim is to arrive at a complete design of this branch by the end of 2021, which, pending the approval of the CERN scientific committees, could be envisaged for construction after 2024. This timescale is compatible with requests for measurements by various large international collaborations, in the next 10-year horizon.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB130

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paper received ※ 15 May 2021 paper accepted ※ 27 July 2021 issue date ※ 27 August 2021

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THPAB143

M2 Experimental Beamline Optics Studies for Next Generation Muon Beam Experiments at CERN

experiment, hadron, detector, collider

4041

D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, G.L. D’Alessandro, A. Gerbershagen, E. Montbarbon, C.A. Mussolini, E.G. Parozzi, B. Rae, B.M. Veit
CERN, Geneva, Switzerland
L. Gatignon
Lancaster University, Lancaster, United Kingdom

In the context of the Physics Beyond Colliders Project, various new experiments have been proposed for the M2 beamline at the CERN North Area fixed target experimental facility. The experiments include MUonE, NA64µ, and the successor to the COMPASS experiment, tentatively named AMBER/NA66. The AMBER/NA66 collaboration proposes to build a QCD facility requiring conventional muon and hadron beams for runs up to 2024 in the first phase of the experiment. MUonE aims to measure the hadronic contribution to the vacuum polarization in the context of the (gµ-2) anomaly with a setup longer than 40 m and a 160 GeV/c high intensity, low divergence muon beam. NA64µ is a muon beam program for dark sector physics requiring a 100 - 160 GeV/c muon beam with a 15-25 m long setup. All three experiments request similar beam times up to 2024 with compelling physics programs, which required launching extensive studies for integration, installation, beam optics, and background estimations. The experiments will be presented along with details of the studies performed to check their feasibility and compatibility with an emphasis on the updated optics for these next-generation muon beam experiments.

Poster THPAB143 [14.259 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB143

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paper received ※ 17 May 2021 paper accepted ※ 20 July 2021 issue date ※ 25 August 2021

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THPAB168

Optics Measurement by Excitation of Betatron Oscillations in the CERN PSB

injection, dipole, kicker, MMI

4078

E.H. Maclean, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, J. Dilly, E. Fol, H. Garcia Morales, M. Hofer, J. Keintzel, M. Le Garrec, T.E. Levens, L. Malina, T.H.B. Persson, T. Prebibaj, E. Renner, P.K. Skowroński, F. Soubelet, R. Tomás García, A. Wegscheider, L. van Riesen-Haupt
CERN, Geneva, Switzerland

Optics measurement from analysis of turn-by-turn BPM data of betatron oscillations excited with a kicker magnet has been employed very successfully in many machines but faces particular challenges in the CERN PSB where BPM to BPM phase advances are sub-optimal for optics reconstruction. Experience using turn-by-turn oscillation data for linear optics measurements during PSB commissioning in2021 is presented, with implications for the prospect of such techniques in the PSB more generally.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB168

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paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 27 August 2021

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THPAB180

Simulation of 4D Emittance Measurement at the Spallation Neutron Source

emittance, quadrupole, simulation, space-charge

4119

A.M. Hoover
UTK, Knoxville, Tennessee, USA
N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA

Similar to the KV distribution, the Danilov distribution has an elliptical shape and uniform density in the transverse plane and maintains these properties under any linear transport. Efforts are underway at the Spallation Neutron Source (SNS) to paint a Danilov distribution in the accumulator ring. After the beam has been painted, the level to which it approximates an ideal Danilov distribution must be quantified. One way to do this is to measure the four-dimensional emittance, which is ideally zero due to linear relationships between the phase space variables. To measure this emittance, we will utilize a standard method of reconstructing the covariance matrix using various optics settings in conjunction with beam profile measurements. We present the results of preliminary simulations which aim to optimize this measurement scheme for the SNS Ring to Target Beam Transport (RTBT) line.

Poster THPAB180 [2.525 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB180

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 25 August 2021

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THPAB232

Study of Nonlinear Properties of ESR via Tune Scans

quadrupole, closed-orbit, 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, closed-orbit, 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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THPAB328

Tapered Modular Quadrupole Magnet to Reduce Higher-Order Optical Aberrations

quadrupole, focusing, simulation, operation

4429

Y.Z. Shao, G.E. Lawler, B. Naranjo, J.B. Rosenzweig
UCLA, Los Angeles, USA

Funding: US Department of Energy under the contract Nos. DE-SC0017648, DE-SC0009914 and National Science Foundation Grant No. PHY-1549132m
At UCLA’s SAMURAI Laboratory, there will be a need for beam optics to accommodate operation over a range of beam energies. We present a modular quadrupole design that, in addition to satisfying this requirement, incorporates interchangeable tapered end-pieces for mitigation of higher-order aberrations *. The design progresses in an iterative fashion, whereby the tapered shapes, generated algorithmically, are fed into a field solver, and then the aberrations of the resulting particle trajectories are calculated and minimized.
* R. Baartman, Quadrupole shapes, Phys. Rev. ST Accel. Beams 15, 074002 (2012).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB328

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 20 August 2021

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THPAB335

Optical Phase Space Mapping Using a Digital Micro-Mirror Device

experiment, radiation, GUI, controls

4439

M. Vujanovic, R.B. Fiorito, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
A.L. Kippax
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
Optical transition radiation (OTR) is routinely used to measure transverse beam size, divergence , and emittance of charged particle beams. Presented here is an experimental method, which uses micro-mirror device (DMD) to conduct optical phase space mapping (OPSM). OPSM will be a next step and significant enhancement of the measurements capabilities of an adaptive optics-based beam characterization system. For this measurements, a DMD will be used to generate a reflective mask that replicates the double slit. Since the DMD makes it possible to easily change the size, shape and position of the mask, the use of the DMD will greatly simplify OPSM and make it more flexible, faster and more useful for diagnostics applications. The process can be automated and integrated into a control system that can be used to optimize the beam transport.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB335

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paper received ※ 20 May 2021 paper accepted ※ 27 July 2021 issue date ※ 28 August 2021

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