IPAC2021 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOPAB007	Prospect for Interaction Region Local Coupling Correction in the LHC Run 3	coupling, optics, 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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MOPAB008	Exploiting the Beam-Beam Wire Demonstrators in the Next LHC Run 3	octupole, luminosity, operation, experiment	65
	A. Poyet Université Grenoble Alpes, Grenoble, France S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, A. Rossi, G. Sterbini CERN, Geneva, Switzerland K. Skoufaris University of Crete, Heraklion, Crete, Greece
	After the successful experiments performed during the LHC Run 2 with the Beam-Beam Wire demonstrators installed, on Beam 2, in the frame of the HL-LHC project, two of the four wire demonstrators were moved to Beam 1. The objective is to gain operational experience with the wire compensation also on that beam and therefore fully exploit the demonstrators’ potential. This paper proposes a numerical validation of the wire implementation using Run 3 scenarios and explores the optimization of those devices in that respect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB008
About •	paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 11 August 2021
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MOPAB021	A Dispersive Quadrupole Scan Technique for Transverse Beam Characterization	SRF, emittance, optics, 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, optics, beam-losses, 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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MOPAB026	RHIC Delayed Abort Experiments	experiment, kicker, injection, dipole	126
	M. Valette, D. Bruno, K.A. Drees, K.M. Hartmann, G. Heppner, K. Mernick, C. Mi, J.-L. Mi, R.J. Michnoff, J. Morris, F. Orsatti, E. Rydout, T. Samms, J. Sandberg, V. Schoefer, C. Schultheiss, T.C. Shrey, C. Theisen BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. For RHIC to operate at its top energy (100 GeV/n) while protecting the future sPHENIX detector, spontaneous and asynchronous firing of abort kicker modules (pre-fires) have to be avoided. A new triggering circuit for the abort kickers was implemented with relatively slow mechanical relays in series with the standard fast thyratron tubes. The relays prevents unwanted pre-fires during operation, but comes at the expense of a long latency - about 7 milliseconds - between the removal of beam permit and the actual firing of the abort kickers. Protection considerations of RHIC’s superconducting magnets forbid delaying energy extraction from the main dipoles and quadrupoles for too long after a quench. The beam has thus to circulate in both RHIc rings for a few milliseconds as the current in dipole and quadrupole circuit is being extracted. We present the results of delayed abort experiments conducted in July 2018 with the analysis of fast orbit and tune measurements and discuss the safety implications of this implementation for future RHIC operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB026
About •	paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 23 August 2021
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MOPAB035	Modified Lattice of the Compact Storage Ring in the cSTART Project at Karlsruhe Institute of Technology	sextupole, lattice, octupole, storage-ring	159
	A.I. Papash, E. Bründermann, B. Härer, A.-S. Müller, R. Ruprecht, J. Schäfer, M. Schuh KIT, Karlsruhe, Germany
	A very large acceptance compact storage ring (VLA-cSR) is under design at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT, Germany). The combination of a compact storage ring and a laser wakefield accelerator (LWFA) might be the basis for future compact light sources and advancing user facilities. Meanwhile, the post-LWFA beam should be adapted for storage and accumulation in a dedicated storage ring. Modified geometry and lattice of a VLA-cSR operating at 50 MeV energy range have been studied in detailed simulations. The main features of a new model are described here. The new design, based on 45° bending magnets, is suitable to store the post-LWFA beam with a wide momentum spread (1% to 2%) as well as ultra-short electron bunches in the fs range from the Ferninfrarot Linac- Und Test- Experiment (FLUTE). The DBA-FDF lattice with relaxed settings, split elements, and higher-order optics of tolerable strength allows improving the dynamic aperture to an acceptable level. This contribution discusses the lattice features in detail and different possible operation schemes of a VLA-cSR.
	Poster MOPAB035 [1.405 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB035
About •	paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 24 August 2021
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MOPAB056	Optimization of a TBA with Stable Optics and Minimal Longitudinal Dispersion and CSR-Induced Emittance Growth	emittance, bunching, synchrotron, FEL	241
	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) In the beam transfer line which often consists of dipoles to deflect the beam trajectory, longitudinal dispersion effect and emission of coherent synchrotron radiation (CSR) will lead to beam phase space distortion, thus degrading the machine performance. In this study, optimizations of a triple-bend achromat (TBA) cell are conducted using the multi-objective particle swarm optimization (MOPSO) method to suppress the CSR-induced emittance growth and minimize the longitudinal dispersion functions up to high orders, simultaneously. For the longitudinal dispersion function, results of three optimization settings are reported, which makes the TBA design first-order, second-order, and higher-order isochronous. Furthermore, we study the shortest possible beamline length of the higher-order isochronous TBA design, which may pave the way to designing a more compact beam transfer line.
	Poster MOPAB056 [0.366 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB056
About •	paper received ※ 12 May 2021 paper accepted ※ 28 May 2021 issue date ※ 15 August 2021
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MOPAB059	Tools for Use of Generalized Gradient Expansions in Accelerator Simulations	lattice, dipole, simulation, septum	253
	M. Borland, R.R. Lindberg, R. Soliday, A. Xiao ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A common assumption in simulation of accelerators is that the magnets can be approximated using a hard-edge model, perhaps with some edge effects implemented in an impulse approximation. This is usually a good assumption but ignores details of the longitudinal variation of the magnetic fields, which makes it straightforward to implement symplectic tracking. Use of generalized gradient expansions* provides an alternative approach that can suppress numerical deficiencies that may be present in computed or measured 3D field maps. However, the computation of the expansions is not particularly straightforward. In this note, we describe several recently-developed tools that make this process fairly painless and allow tracking with such expansions in the program ELEGANT*. We show several examples of using the tools for simulations related to the Advanced Photon Source Upgrade. M. Venturini et al., NIM A 427, 387 (1999). ** M. Borland, Advanced Photon Source LS-287, September 2000
	Poster MOPAB059 [4.311 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB059
About •	paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 18 August 2021
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MOPAB063	Commissioning Strategy for Diamond-II	MMI, lattice, optics, 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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MOPAB089	Effect of Different Models of Combined-function Dipoles on the HEPS Parameters	dipole, lattice, storage-ring, emittance	335
	Y.Y. Guo, Y. Jiao, N. Li IHEP, Beijing, People’s Republic of China
	The high energy photon source (HEPS) is a 6 GeV, kilometer-scale storage ring light source being built in Beijing, China. In the current ring lattice, the combined-function dipoles are used and assumed to have constant dipole field. However, in the actual magnet design, an eccentrically placed quadrupole is adopted, in which the bending field along the trajectory is not constant. In this paper, we will present the effect of the two models of combined-function dipoles on the parameters of the storage ring.
	Poster MOPAB089 [0.590 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB089
About •	paper received ※ 13 May 2021 paper accepted ※ 25 May 2021 issue date ※ 27 August 2021
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MOPAB101	Hollow and Flat Electron Beam Generation at FACET-II	electron, emittance, wakefield, experiment	376
	A. Halavanau, S.J. Gessner, C.E. Mayes SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA
	In this proceeding, we investigate hollow and flat electron beam generation at FACET-II facility. We focus on the case of a circular beamlet arrangement, also known as ’necklace’ beams. We study, via numerical simulations, the resulting e-beam dynamics in the FACET-II photoinjector, beam propagation through the high energy section, as well as possible experimental applications of the ’necklace’ beams. Finally, we evaluate the feasibility of high charge flat beam generation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB101
About •	paper received ※ 23 May 2021 paper accepted ※ 27 July 2021 issue date ※ 23 August 2021
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MOPAB103	Study of Transverse Oscillation Coupling and Possibility of Its Minimization in SKIF (Novosibirsk)	coupling, emittance, sextupole, storage-ring	383
	D. Leshenok BINP, Novosibirsk, Russia G.N. Baranov, E.B. Levichev, S.A. Nikitin BINP SB RAS, Novosibirsk, Russia
	The vertical emittance and, in general, the vertical beam size and angular divergence are of paramount importance in the SKIF (Russian acronym for Siberian Circular Photon Source) project developed in Novosibirsk. Therefore, a detailed simulation of the corresponding influence of possible errors in the storage ring was carried out with cross-validation by different methods. Variants of cross-coupling correction are proposed and modeled to obtain a vertical emittance of the order of one picometer simultaneously with minimizing vertical dispersion.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB103
About •	paper received ※ 18 May 2021 paper accepted ※ 17 August 2021 issue date ※ 19 August 2021
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MOPAB139	High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM	experiment, electron, focusing, target	485
	G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas RadiaBeam, Marina del Rey, California, USA M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu BNL, Upton, New York, USA C.C. Hall RadiaSoft LLC, Boulder, Colorado, USA
	Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139
About •	paper received ※ 26 May 2021 paper accepted ※ 28 May 2021 issue date ※ 18 August 2021
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MOPAB151	A Stable Drive Beam for High Gradient Dielectric Wakefield Acceleration	focusing, wakefield, accelerating-gradient, acceleration	528
	T.J. Overton, Y.M. Saveliev, G.X. Xia Cockcroft Institute, Warrington, Cheshire, United Kingdom T.J. Overton, G.X. Xia The University of Manchester, Manchester, United Kingdom T.H. Pacey, Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Funding Council (STFC) student grant. A high accelerating gradient, with stable beam transport, is necessary for the next generation of particle accelerators. Dielectric wakefield accelerators are a potential solution to this problem. In these proceedings, we present simulation studies of electron bunches in the self-wake regime inside a planar dielectric structure. This is analogous to driving beams in a dielectric wakefield accelerator. The transverse and longitudinal wake fields are investigated for dielectric plate gaps, various transverse beam sizes, and longitudinal bunch profiles. The effects of these on the stability of drive bunches, and acceleration of a witness bunch, are discussed in the context of electron bunches that can be produced with conventional linac RF technology.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB151
About •	paper received ※ 13 May 2021 paper accepted ※ 07 June 2021 issue date ※ 24 August 2021
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MOPAB164	Miniature, High Strength Transport Line Design for Laser Plasma Accelerator-Driven FELs	laser, electron, plasma, undulator	561
	S. Fatehi, A. Bernhard, A.-S. Müller, M.S. Ning KIT, Karlsruhe, Germany
	Funding: This work is supported by the BMBF project 05K19VKA PlasmaFEL (Federal Ministry of Education and Research). Laser-plasma acceleration is an outstanding candidate to drive the next-generation compact light sources and FELs. To compensate large chromatic effects using novel compact beam optic elements in the beam transport line is required. We aim at designing miniature, high strength, normal conducting and superconducting transport line magnets and optics for capturing and matching LPA-generated electron bunches to given applications. Our primary application case is a demonstration experiment for transverse gradient undulator (TGU) FELs, to be performed at the JETI laser facility, Jena, Germany. In this contribution, we present the current design of the beam transport line magnets and the beam optics calculations. Laser Plasma Accelerators, FELs, Magnets, Beam Dynamics, Superconductivity, transverse gradient undulator
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB164
About •	paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 20 August 2021
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MOPAB179	Simulations of AGS Boosters Imperfection Resonances for Protons and Helions	resonance, proton, simulation, experiment	606
	K. Hock, H. Huang, F. Méot, N. Tsoupas BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. As part of the effort to increase the polarization of the proton beam for the physics experiments at RHIC, a scan of orbit harmonic corrector strengths is performed in the Booster to ensure polarization transmission through the \|G gamma\|=3 and 4 imperfection resonances is optimized. These harmonic scans have been simulated using quadrupole alignment data and accurately match experimental data. The method used to simulate polarized protons is extended to polarized helions for crossing the \|G gamma\|=5 through \|G gamma\|=10 imperfection resonances and used to determine the corrector strength required to cross each resonance.
	Poster MOPAB179 [0.437 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB179
About •	paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 02 September 2021
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MOPAB184	Unsupervised Learning Techniques for Tune Cleaning Measurement	ISOL, optics, coupling, luminosity	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	optics, 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	optics, 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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MOPAB195	Development of a Disk-and-Washer Cavity for the J-PARC Muon g-2/EDM Experiment	cavity, experiment, linac, coupling	658
	Y. Takeuchi, J. Tojo Kyushu University, Fukuoka, Japan E. Cicek, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan R. Kitamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue, K. Sumi, M. Yotsuzuka Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	At J-PARC, an experiment using muons accelerated by a linac is planned to measure the anomalous magnetic moment of muons and to search for the electric dipole moment. A 1296 MHz disk and washer (DAW) coupled cavity linac (CCL) is being developed for use in the middle beta section of the muon linac. The DAW CCL consists of 14 tanks with 11 cells each. All tanks are connected by bridge couplers and electromagnetic quadrupole doublets for focusing are installed in each bridge coupler. The basic design of the DAW cavity has already been completed, and now detailed cavity design studies and manufacturing process studies are underway. In this poster, we will report about these studies and the preparation status of manufacturing the DAW cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB195
About •	paper received ※ 20 May 2021 paper accepted ※ 01 June 2021 issue date ※ 23 August 2021
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MOPAB196	Field tuning of the 1 MeV/n RFQ at KOMAC	rfq, ion-source, dipole, solenoid	662
	H.-J. Kwon, Y.-S. Cho, J.J. Dang, W.-H. Jung, D.-H. Kim, H.S. Kim, K.H. Kim, S. Lee Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
	Funding: This work was supported by the Korea Multi-purpose Accelerator Complex (KOMAC) operation funds through Ministry of Science and ICT (MIST) of Korean Government. A 1 MeV/n Radio-frequency Quadrupole (RFQ) is under development at Korea Multi-purpose Accelerator Complex (KOMAC), the purposes of which are swift ion beam irradiation and compact neutron source. The RFQ was designed to accelerate ions with mass to charge (A/q) ratio up to 2.5. The designed peak current was 10 mA with 10% duty ratio. The RFQ is four vane structure resonated at 200 MHz. It has total 40 frequency tuners. There are no dipole rods and resonant coupling plate because the mode separation was large enough and the length of the RFQ was only two times of the wavelength. In this paper, the development status and field tuning results of the 1 MeV/n RFQ are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB196
About •	paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 20 August 2021
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MOPAB214	Linear Optics Measurement for the APS Ring with Turn-by-Turn BPM Data	optics, 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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MOPAB220	Towards Deterministic Design of MBA-Lattices	dipole, lattice, emittance, sextupole	722
	B.C. Kuske HZB, Berlin, Germany
	Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association Since the pioneering work of MAX IV , multi-bend achromat (MBA) lattices have become the standard in lattice design for 4th generation lights sources as well as upgrades of 3rd generation storage rings. The distribution of the bending angle to many weak dipoles enables to reach unprecedented low emittance and highest brightness. In their most basic form, MBA-lattices consist of a repetitive unit cell and two identical matching cells on either end of the achromatic arc. The simplicity of both cells allows for a unique determination of the linear lattice parameters in dependence on boundary conditions defined by the design goals. Those might be the emittance, momentum compaction factor, chromaticity, as well as phase advances with respect to achieving higher-order achromatic structures. A scan of optional lattice prototypes is quickly obtained. We demonstrate this concept and apply it in the design of the first candidates for the lattice of BESSY III, a green-field 4th generation storage ring being currently planned at HZB, Berlin, Germany. https://www.maxiv.lu.se/accelerators-beamlines/accelerators/accelerator-documentation/max-iv-ddr/
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB220
About •	paper received ※ 17 May 2021 paper accepted ※ 23 July 2021 issue date ※ 26 August 2021
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MOPAB230	The Optics Design for the Final Focus System of CLIC 380 GeV	optics, luminosity, sextupole, 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, optics, alignment, simulation	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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MOPAB239	Simulation and Optimization of the Spin Coherence Time of Protons in a Prototype EDM Ring	storage-ring, dipole, simulation, polarization	771
	M. Vitz, A. Lehrach FZJ, Jülich, Germany R. Shankar INFN-Ferrara, Ferrara, Italy
	The matter-antimatter asymmetry might be understood by investigating the EDM (Electric Dipole Moment) of elementary charged particles. A permanent EDM of a subatomic particle violates time-reversal and parity symmetry at the same time and would be, with the currently achievable experimental accuracy, a strong indication for physics beyond the Standard Model. The JEDI-Collaboration (Jülich Electric Dipole moment Investigations) in Jülich is preparing a direct EDM measurement for protons and deuterons: first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. A prototype EDM ring is an intermediate step before building the final storage ring to demonstrate sufficient beam lifetime and SCT (Spin Coherence Time) in a pure electrostatic ring as well as in a storage ring with combined electric and magnetic bending elements. In order to study the effect of E-B-deflectors on the orbit and the spin motion, the software library Bmad is used. The first results of the optics and spin simulations, with a focus on the optimization of the SCT, towards the prototype EDM ring will be discussed.
	Poster MOPAB239 [0.560 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB239
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 23 August 2021
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MOPAB242	A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring	lattice, storage-ring, emittance, dipole	782
	J. Li, M. Abo-Bakr, P. Goslawski HZB, Berlin, Germany Z.H. Bai USTC/NSRL, Hefei, Anhui, People’s Republic of China
	HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021
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MOPAB246	Design of the MEBT for the JAEA-ADS Project	MEBT, linac, emittance, rfq	790
	B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	The Medium Energy Beam Transport (MEBT) will transport a CW proton beam with a current of 20 mA and energy of 2.5 MeV from the exit of the normal conducting Radiofrequency Quadrupole (RFQ) to the superconducting Half-Wave resonator (HWR) section. The MEBT must provide a good matching between the RFQ and HWR, effective control of the emittance growth and the halo formation, enough space for all the beam diagnostics devices, among others. This work reports the first lattice design and the beam dynamics studies for the MEBT of the JAEA-ADS.
	Poster MOPAB246 [0.827 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB246
About •	paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 19 August 2021
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MOPAB253	Comparison of Transfer Map Derivation Methods for Static Magnetic Fields	multipole, lattice, extraction, operation	799
	J.A. Crittenden, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811. We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253
About •	paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 13 August 2021
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MOPAB254	Measurement of Horizontal Beam Size Using Sextupole Magnets	sextupole, storage-ring, positron, dipole	802
	J.A. Crittenden, K.E. Deitrick, H.X. Duan, G.H. Hoffstaetter, V. Khachatryan, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by National Science Foundation award number DMR-1829070. The quadratic dependence of sextupole fields on position results in a beam-size-dependent kick on a beam traversing a sextupole magnet. A change in sextupole strength changes the closed orbit and the tune of the beam in a storage ring. Measuring both therefore allows conclusions about the beam size in the sextupole. Here we derive the pertinent formula and discuss the applicability to storage rings. In particular we investigate the measurement accuracy that can be achieved at the Cornell High Energy Synchrotron Source. The Cornell Electron-positron Storage Ring underwent a major upgrade in 2018 with the goal of reducing the emittance by a factor of four. A variety of beam size measurement methods have been developed to monitor the positron beam size, including visible synchrotron light and interferometry. We investigate the sensitivity of the sextupole method and compare to other measurement techniques. The design horizontal emittance of the 6-GeV positron beam is about 30 nm-rad with typical beam sizes of about 1 mm, setting the scale for the required accuracy in the beam-size measurement.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB254
About •	paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 01 September 2021
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MOPAB260	Optics Corrections with LOCO on Sirius Storage Ring	optics, 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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MOPAB261	NSLS-II Storage Ring Lattice Analysis using Response Matrices	lattice, alignment, storage-ring, sextupole	829
	J. Choi BNL, Upton, New York, USA
	Funding: Work supported by the U.S. Department of Energy (DOE) under contract No. DE-SC0012704. Affected from various sources, the NSLS-II storage ring lattice is slightly changing operation to operation and, for the operational performance, we are continually optimizing the lattice and maintaining the response matrices for the feedback and lattice analysis. Because not all sources are identified, we are investing efforts to identify as many as possible. As one of such efforts, we also study the measured response matrices. In this paper, we present the results of lattice studies using a pair of recently measured response matrices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB261
About •	paper received ※ 20 May 2021 paper accepted ※ 02 June 2021 issue date ※ 19 August 2021
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MOPAB264	Commissioning of the DESIR High-Resolution Separator at CENBG	emittance, multipole, MMI, dipole	841
	J. Michaud, P. Alfaurt, A. Balana, B. Blank, L. Daudin, T. Kurtukian-Nieto, S. Leblanc, L.S. Serani CENBG, Gradignan, France F. Méot BNL, Upton, New York, USA F. Varenne GANIL, Caen, France
	DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. The high-resolution mass separator (HRS) included in DESIR is a 180 degree symmetric online separator with two 90 degree magnetic dipole sections arranged with electrostatic quadrupoles, sextupoles and a multipole on the mid plane. The HRS is now completely mounted at CENBG and under commissioning for the next 2 to 3 years before its transfer at the entrance of the DESIR facility. The objective is to test, characterise and correct all HRS elements contributing to the higher order aberration by performing experimental measurements and comparing them with the results from different simulation tools. The recently mounted pepperpot-type emittance-meter will allow us to observe the emittance figures and dynamically tune the multipole to improve the optical parameters of the HRS. We will present the first results concerning the hexapolar correction with the multipole, the associated emittance measurements and the resolution currently achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB264
About •	paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 10 August 2021
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MOPAB269	Three Approaches for Complete Measurement of the Transverse Beam Optics Along the Fermilab Muon Campus Extraction Line	extraction, dipole, optics, 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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MOPAB277	Installation, Use and Follow-Up of an Emittance-Meter at the Arronax Cyclotron 70XP	emittance, cyclotron, injection, ECR	877
	F. Poirier, R. Bellamy, F. Bulteau-Harel, C. Castel, T. Durand, X. Goiziou, F. Haddad, C. Koumeir, R. Lelièvre, G. Mechin, L. Perrigaud, J. Poudevigne, H. Trichet Cyclotron ARRONAX, Saint-Herblain, France T. Adam, P.G. Graehling, M. Heine, C. Maazouzi, F.R. Osswald, E.K. Traykov IPHC, Strasbourg Cedex 2, France A. Dinkov, S. Wurth IJCLab, ORSAY, France F. Haddad SUBATECH, Nantes, France
	Funding: This work is supported by grants from the ANR program "Investissements d’Avenir", n°ANR-11-EQPX-0004, n°ANR-11-LABX-18-01 and n°ANR-16-IDE-0007 and by a PhD scholarship from CNRS/IN2P3. The 70 MeV cyclotron group of the Arronax GIP (Interest Public Group), France, foresees to increase its beam intensity on target. For this, several beam studies are being performed in the various sections of the accelerator including the injection. Thus, an Allison-type emittance-meter has been installed in this section above the cyclotron and downstream a quadrupole triplet. Installation and the first results of a campaign of measurements are presented including high intensity runs, up to 1 mA for 40 keV H⁻ ions. The emittance-meter is expected to be used with several accelerators throughout the world. Therefore, a strategy on the follow-up of the activation of sample materials used in the equipment is being established and is described in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB277
About •	paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 12 August 2021
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MOPAB295	Simulation Study of Emittance Measurement Using a Genetic Algorithm for Space Charge Dominated Beams	emittance, space-charge, simulation, lattice	935
	H.D. Zhang, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom
	Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 under and the STFC Cockcroft core grant No. ST/G008248/1. The quadrupole scan method is one of the traditional ways to measure beam emittance in an accelerator. The required devices are simple: several quadrupole magnets and a beam profile monitor. Beam sizes are measured from the beam profile monitor with different quadrupole settings to bring the beam through its waist and then fitted to a quadratic equation to determine the Twiss parameters. measured data from a quadrupole scan taking the beam through its waist is fitted to a quadratic equation and this allows determining the Twiss parameters. However, with increasing beam intensity, the transfer function becomes non-linear and this causes a deviation of the fitted emittance from its real value, making it no longer useful. In this contribution, a genetic algorithm is applied to find the optimum quadrupole scan fit in space-charge dominated electron beams. Results from simulations using different space charge levels are presented and scenarios identified where this method can be applied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB295
About •	paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 02 September 2021
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MOPAB302	Characterization of the Full Transverse Phase Space of Electron Bunches at ARES	simulation, experiment, electron, linac	952
	S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, H. Dinter, W. Kuropka, F. Mayet, T. Vinatier DESY, Hamburg, Germany R.W. Aßmann INFN/LNF, Frascati, Italy S. Jaster-Merz University of Hamburg, Hamburg, Germany
	The ARES linear accelerator at the SINBAD facility (DESY) is dedicated to perform accelerator R&D studies with sub-fs short electron bunches to test novel acceleration techniques and diagnostics devices. Currently, the commissioning of the linac is ongoing and first experiments are being performed. For this, the knowledge of the full phase space of the particle beams is of high interest to, for example, optimize the accelerator performance and identify possible errors in the beam line. Tomographic methods can be used to gain insight into the full 4D transverse phase space and its correlations. Here, simulation results and first experimental preparations of a 4D transverse phase-space tomography of electron bunches at ARES are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB302
About •	paper received ※ 17 May 2021 paper accepted ※ 16 June 2021 issue date ※ 30 August 2021
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MOPAB304	Beam Diagnostics for Multi-Objective Bayesian Optimization at the Argonne Wakefield Accelerator Facility	emittance, diagnostics, dipole, wakefield	960
	J.P. Gonzalez-Aguilera, Y.K. Kim University of Chicago, Chicago, Illinois, USA W. Liu, P. Piot, J.G. Power, E.E. Wisniewski ANL, Lemont, Illinois, USA R.J. Roussel Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
	Particle accelerators must achieve certain beam quality objectives for use in different experiments. Usually, optimizing certain beam objectives comes at the expense of others. Additionally, there are many input parameters and a limited number of diagnostics. Therefore, accelerator tuning becomes a multi-objective optimization problem with a limited number of observations. Multi-objective Bayesian optimization was recently proposed as an efficient method to find the Pareto front for an online accelerator tuning problem with reduced number of observations. In order to experimentally test the multi-objective Bayesian optimization method, a novel accelerator diagnostic is being designed to measure multiple beam quality metrics of an electron beam at the Argonne Wakefield Accelerator Facility. Here, we present a design consisting in a pepper-pot mask, a dipole magnet and a scintillation screen, which allows a simultaneous measurement of the electron beam energy spread and vertical emittance. Additionally, a surrogate model for the vertical emittance was constructed with only 60 observations and without prior knowledge of the objective function nor diagnostics constraints.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB304
About •	paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 26 August 2021
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MOPAB353	Design of a compact Ka-Band Mode Launcher for High-gradient Accelerators	cavity, coupling, simulation, accelerating-gradient	1100
	G. Torrisi, G.S. Mauro, G. Sorbello INFN/LNS, Catania, Italy M. Behtouei, L. Faillace, B. Spataro, A. Variola INFN/LNF, Frascati, Italy V.A. Dolgashev SLAC, Menlo Park, California, USA L. Faillace, M. Migliorati Sapienza University of Rome, Rome, Italy M. Migliorati INFN-Roma1, Rome, Italy J.B. Rosenzweig UCLA, Los Angeles, California, USA G. Sorbello University of Catania, Catania, Italy
	In this work, we present the RF design of a table-top Ka-Band mode launcher operating at 35.98 GHz. The structure consists of a symmetrical 4-port WR28 rectangular-TE10-to-circular-TM01 mode converter that is used to couple a peak output RF power of 5 MW (pulse length up to 50 ns and repetition rate up to 100 Hz) in Ka-Band linear accelerator able to achieve very high accelerating gradients (up to 200 MV/m). Numerical simulations have been carried out with the 3D full-wave commercial simulator Ansys HFSS in order to obtain a preliminary tuning of the accelerating field flatness at the operating frequency f0=35.98 GHz. The main RF parameters, such as reflection coefficient, transmission losses, and conversion efficiency are given together with a verification of the field azimuthal symmetry which avoids dipole and quadrupole deflecting modes. To simplify future manufacturing, reduce fabrication costs, and also reduce the probability of RF breakdown, the proposed new geometry has "open" configuration. This geometry eliminates the flow of RF currents through critical joints and allows this device to be milled from metal blocks.
	Poster MOPAB353 [3.131 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB353
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021
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MOPAB374	Creating Exact Multipolar Fields in Accelerating RF Cavities via an Azimuthally Modulated Design	cavity, simulation, dipole, collider	1154
	L.M. Wroe, S.L. Sheehy JAI, Oxford, United Kingdom R. Apsimon Cockcroft Institute, Lancaster University, Lancaster, United Kingdom M. Dosanjh CERN, Meyrin, Switzerland S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia
	In this paper, we present a novel method for designing RF structures with specifically tailored multipolar field contributions. This has a range of applications, including the suppression of unwanted multipolar fields or the introduction of wanted terms, such as for quadrupole focusing. In this article, we outline the general design methodology and compare the expected results to 3D CST simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB374
About •	paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 23 August 2021
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MOPAB376	Design and Fabrication of a Quadrupole Resonator for SRF R&D	SRF, cavity, niobium, radio-frequency	1158
	R. Monroy-Villa, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany S. Gorgi Zadeh, P. Putek Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany R. Monroy-Villa, D. Reschke, J.H. Thie DESY, Hamburg, Germany
	As Nb superconducting radio-frequency (SRF) cavities are now approaching the theoretical limits of the material, a variety of different surface treatments have been developed to further improve their performance; although no fully understood theory is yet available. Small superconducting samples are studied to characterize their material properties and their evolution under different surface treatments. To study the RF properties of such samples under realistic SRF conditions at low temperatures, a test cavity called quadrupole resonator (QPR) is currently being fabricated. In this work we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB and its design will allow for testing samples under cavity-like conditions, i.e., at temperatures between 2K and 8 K, under magnetic fields up to 120mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with a status report on the current manufacturing process, will be presented.
	Poster MOPAB376 [1.119 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB376
About •	paper received ※ 26 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021
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TUXC07	Modified Halbach Magnets for Emerging Accelerator Applications	permanent-magnet, dipole, collider, electron	1315
	S.J. Brooks BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The original circular Halbach magnet design creates a strong pure multipole field from permanent magnet pieces without intervening iron. This design has been extended recently at the CBETA 4-turn ERL, whose return loop includes combined-function (dipole+quadrupole) Halbach-derived magnets, plus a modular system of tuning shims to improve all 216 magnets’ relative field accuracy to better than 10^-3. This paper describes further modifications of the Halbach design enable a larger range of accelerator applications in the future: (1) open-midplane designs to allow synchrotron radiation in light sources and other high-energy electron rings, ERLs or RLAs to escape. (2) Quadrupole magnets with an oval aperture allow larger gradients than a circular aperture, provided the beam is more extended in one axis than the other, as usual for a quadrupole in a focussing system. These can be used in compact hadron therapy gantries. (3) New collider complexes often require multiple rings for acceleration or top-up, accumulation, collision and cooling. Multi-aperture permanent magnets are possible to cheaply and compactly build ring systems with several stable orbits separated by a few cm.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC07
About •	paper received ※ 14 May 2021 paper accepted ※ 08 July 2021 issue date ※ 23 August 2021
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TUPAB005	Emittance Estimates for the Future Circular Collider	emittance, alignment, simulation, sextupole	1338
	L. van Riesen-Haupt, T.K. Charles, R. Tomás García, F. Zimmermann CERN, Meyrin, Switzerland T.K. Charles The University of Liverpool, Liverpool, United Kingdom
	The alignment strategy of the FCC-ee has a large impact on its luminosity. Larger alignment tolerances result in increased coupling and a subsequently higher vertical emittance. At the same time, tighter alignment tolerances around the 100 km ring are a major cost driver. This paper applies analytical emittance estimate methods to the FCC-ee and compares their predictions to data from simulations with different alignment tolerances. These methods can be used to help understand the impact of misalignments of certain magnet groups and to come up with an efficient alignment strategy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB005
About •	paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021
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TUPAB006	The Impact of Beam Position Monitor Tilts on Coupling Measurements	coupling, resonance, optics, simulation	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, emittance, alignment, optics	1346
	B. Wang, Y. Wang, Y. Wei, C.H. Yu, Y. Zhang IHEP, Beijing, People’s Republic of China
	This paper describes the error correction scheme for the CEPC CDR lattice in Higgs mode, which has a small beta function at the interaction point. The low emittance optics has an enhanced sensitivity to the magnet misalignments and field errors, especially for the final focus quadrupole misalignment. The magnet imperfection will cause the closed orbit distortion and optics distortion. The correction scheme for these magnet imperfections includes the closed orbit correction, the dispersion correction, the beta function correction and the betatron coupling correction. The resulting performance and the dynamic aperture for the corrected lattice are studied.
	Poster TUPAB007 [1.075 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB007
About •	paper received ※ 14 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021
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TUPAB008	Progress of the First-Turn Commissioning Simulations for HEPS	simulation, lattice, MMI, dipole	1349
	B. Wang, Z. Duan, D. Ji, Y. Jiao, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is 6 GeV, kilometer-scale, 4th generation storage ring light source. The lattice has an ultralow emittance and strong focusing such that the beam dynamics is very sensitive to the magnet misalignments and other error sources. Getting the first turn and establishing the closed orbit is essential for accelerator commissioning. This paper describes a simulation algorithm for achieving the first turn commission based on the latest HEPS storage ring lattice. We developed a new accelerator toolbox (AT)-based program for automatic optimizing the first turn commissioning. The algorithm and simulation results will be presented in this paper.
	Poster TUPAB008 [0.646 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB008
About •	paper received ※ 14 May 2021 paper accepted ※ 11 June 2021 issue date ※ 28 August 2021
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TUPAB010	Impact of Bunch Current on Optics Measurements in SuperKEKB	optics, damping, impedance, 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	optics, 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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TUPAB016	ESS RFQ: Installation and Tuning at Lund	rfq, insertion, coupling, cavity	1372
	P. Hamel, D. Chirpaz-Cerbat, M. Desmons, A.C. France, O. Piquet CEA-IRFU, Gif-sur-Yvette, France A. Dubois, Y. Le Noa CEA-DRF-IRFU, France
	The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019. It has been provided by CEA, IRFU, Saclay/France. It consists of five sections with a total length of 4.6 m and accelerates the 70 mA proton beam from 75 keV up to 3.6 MeV. It will be fed with 900 kW peak power through two coaxial loop couplers. The installation process (alignment, vacuum test), as well as the tuning process based on bead-pull measurements, is presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB016
About •	paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 14 August 2021
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TUPAB017	Study of Conduction-Cooled Superconducting Quadrupole Magnets Combined with Dipole Correctors for the ILC Main Linac	dipole, linac, SRF, cavity	1375
	Y. Arimoto, S. Michizono, Y. Morikawa, N. Ohuchi, T. Oki, H. Shimizu, K. Umemori, X. Wang, A. Yamamoto, Y. Yamamoto, Z.G. Zong KEK, Ibaraki, Japan V.S. Kashikhin Fermilab, Batavia, Illinois, USA
	A superconducting rf (SRF) cryomodule for International Linear Collider(ILC) Main Linac equips focus/steering magnets. The magnets are "superferric" magnets with four superconducting (SC) race track coils conductively cooled from the cryomodule LHe supply pipe. The quadrupole field gradient and dipole field are 40 T/m and 0.1 T, respectively. The magnet length and iron-pole radius are 1 m and 0.045 m, respectively. It is known that dark current is generated at SRF cavities and accelerated through the following linac string. The dark current reaches and heats the SC magnets. It is estimated that the power deposition in the magnet may reach more than a few watts and temperature of the SC coils may locally reach to critical temperature of NbTi. It is important to make the magnet not reach quench with sufficient conduction cooling. We aim to realize the SC magnet which can stably operate under such condition. We plan to develop test coils made of three types of SC materials, NbTi, Nb₃Sn, and MgB₂ and study thermal characteristics and stability . We will develop a short model magnet, based on the test coil results. Here, we will present the magnet design study and the R&D plan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB017
About •	paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021
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TUPAB059	Measurement of the Advanced Photon Source Lifetime at Different Level of Beta-Beating	betatron, storage-ring, optics, 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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TUPAB083	Dual Energies in the LCLS Copper Linac	linac, feedback, klystron, betatron	1570
	F.-J. Decker, C. Bianchini Mattison, D.K. Bohler, A. Brachmann, W.S. Colocho, S. Condamoor, M.L. Gibbs, K.H. Kim, A.A. Lutman, T.J. Maxwell, J.A. Mock, H.-D. Nuhn, J.C. Sheppard, H. Smith, T.J. Smith, M. Stanek, S. Zelazny, Z. Zhang, C.M. Zimmer SLAC, Menlo Park, California, USA
	For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the superconducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.
	Poster TUPAB083 [0.479 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB083
About •	paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021
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TUPAB094	Multi-Start Foil Wound Solenoids for Multipole Suppression	solenoid, multipole, emittance, simulation	1596
	N. Majernik, A. Fukasawa, J.B. Rosenzweig, A. Suraj UCLA, Los Angeles, California, USA
	Funding: National Science Foundation Grant No. PHY-1549132 - CBB, DE-SC0020409 Solenoids for beam transport are typically wound helically, with each layer of wire being laid down on top of the previous, or as "pancakes" where the wire is wound radially in before crossing over and winding out. Both of these approaches break rotational symmetry and introduce higher-order multipole moments which can be deleterious to beam emittance. For high brightness beams, this can be particularly problematic. To this end, a solenoid employing multi-start foil windings is simulated and compared to conventional choices. With appropriate design, this approach can forbid certain multipoles by symmetry.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB094
About •	paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 15 August 2021
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TUPAB102	A New 2nd Bunch Compression Chicane for the FLASH2020+ Project	dipole, vacuum, focusing, FEL	1618
	M. Vogt, J. Zemella DESY, Hamburg, Germany
	The first stage of the FLASH2020+ project is an upgrade of the FLASH injector beamline. Within this framework, the 2nd bunch compression chicane (BCC) will be completely redesigned. The old S-chicane will be replaced with a new C-chicane which is 3.5m shorter thereby generating space a new section for re-matching the beam from the injector into the linac. The new BCC will be equipped with quad/skew-quad units in both legs of the chicane to compensate correlations of the transverse degrees of freedom with the longitudinal ones. Since quadrupoles tend to have a circular bore, the chicane is designed with movable round vacuum chambers and movable dipoles for maintaining full flexibility in choosing the compression parameters. This article describes the technical details and introduces a thin-lens model of BCCs which allows analytical estimates on the effects of powering the quad/skew-quad units on optics parameters as well as estimates on the required strengths of these magnets in order to remove correlations of the magnitudes typically observed at FLASH.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB102
About •	paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 29 August 2021
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TUPAB104	Redesign of the FLASH2 Post-SASE Undulator Beamline	undulator, electron, photon, MMI	1626
	F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt, J. Zemella DESY, Hamburg, Germany
	FLASH2 is one of the two SASE (Self-Amplified Spontaneous Emission) undulator beamlines lines comprising variable gap undulators to produce radiation in the XUV and soft X-ray regime at FLASH. Downstream of the SASE undulators the beamline is currently undergoing a major redesign. During shutdowns in summer 2020 and winter 2021 two PolariX TDSs (Polarizable X-band Transverse Deflecting Structure) were installed, as well as additional diagnostics, to monitor the longitudinal phase space density of the electron bunches. Additionally, an afterburner undulator will be integrated in the next shutdown to produce circularly polarized light with wavelengths down to 1.39 nm. In this paper, we will present the modifications that were and will be made to the electron beamline in the course of this redesign.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB104
About •	paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 23 August 2021
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TUPAB129	Beam Based Alignment in a Compact THz-FEL Facility	FEL, alignment, linac, undulator	1692
	Q.S. Chen, T. Hu, K.F. Liu, B. Qin, Y.Q. Xiong HUST, Wuhan, People’s Republic of China
	In this paper, we presented the beam based alignment results in a compact THz-FEL facility. The alignment was divided into two sections, the transport line and the optical line. In the transport line, all the five quadrupoles upstream of the undulator were adjusted one by one to fit the electron beam from the traveling wave linac. In the optical line, a set of auxiliary coils were winded on the yokes of the quadrupole downstream of the double bend achromat (DBA) to produce a vertical steering force. Another combined steering magnet, together with the auxiliary coils, corrected the beam orbit in the optical line. With the dispersion free test, the displacement between the magnetic centers of the quads and the beam orbit was less than 0.1mm.
	Poster TUPAB129 [0.673 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB129
About •	paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021
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TUPAB134	Linac-to-Booster Optimization Procedure Towards High Transmission for the Alba Injector	linac, booster, alignment, operation	1703
	R. Muñoz Horta, D. Lanaia, E. Marín, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a third generation synchrotron light source that consists of 3 accelerators (Linac, Booster and Storage ring) and two transfer lines, Linac-to-Booster (LTB) and Booster-to-Storage (BTS). The ALBA accelerators team has defined a robust procedure that optimizes the beam performance from Linac to Booster in terms of transmission and stability. The implemented beam-based alignment and global orbit correction techniques have been investigated first in simulations and afterwards successfully implemented in the machine.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB134
About •	paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021
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TUPAB172	Quadrupole Magnet Design for a Heavy-Ion IH-DTL	heavy-ion, DTL, proton, linac	1793
	P.F. Ma, C.T. Du, X. Guan, M.W. Wang, X.W. Wang, Y.L. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng TUB, Beijing, People’s Republic of China W. Chen, W.L. Liu, W. Lv, M.T. Qiu, B.C. Wang, D. Wang, M.C. Wang, Z.M. Wang, Y.H. Yan, M.T. Zhao NINT, Xi’an, People’s Republic of China
	Xi’an Proton Application Facility (XiPAF) will be upgraded to provide heavy-ion beams with a heavy-ion injector. The injector consists of an ECR heavy-ion source, a Low Energy Beam Transport line (LEBT), a Radio Frequency Quadrupole (RFQ), an Interdigital H-mode Drift Tube Linac (IH-DTL), and a Linac to Ring Beam Transport line (LRBT). The IH-DTL can accelerate the ions with mass to charge up to 6.5 from 0.4 MeV/u to 2 MeV/u. To provide transverse focusing, the electro-magnetic quadrupoles are installed inside the drift tubes of IH-DTL, thus the magnet needs to be high-gradient and compact. This paper gives the quadrupole magnet design for the heavy-ion IH-DTL. The results show that the quadrupole magnet design can meet the requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB172
About •	paper received ※ 08 May 2021 paper accepted ※ 21 June 2021 issue date ※ 23 August 2021
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TUPAB189	Design and Simulation of Beam Transport Lines of DC140 Cyclotron	cyclotron, radiation, target, heavy-ion	1845
	V.I. Lisov, N.S. Kirilkin, A.S. Zabanov JINR/FLNR, Moscow region, Russia I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, V.A. Semin JINR, Dubna, Moscow Region, Russia
	Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The beam transport system has three lines: for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The design and simulation of the beam transport system from cyclotron is presented in this report. The beam focusing in the beam lines is provided by set of quadrupole lenses. The beam diagnostics system consists of the Faraday caps, luminophores and the magnetic scanning system.
	Poster TUPAB189 [0.958 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB189
About •	paper received ※ 14 May 2021 paper accepted ※ 02 June 2021 issue date ※ 17 August 2021
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TUPAB190	Design and Simulation of the Extraction System of DC140 Cyclotron	extraction, cyclotron, focusing, septum	1849
	V.I. Lisov, A.A. Protasov, A.S. Zabanov JINR/FLNR, Moscow region, Russia K. Gikal, G.G. Gulbekyan, I.A. Ivanenko, G.N. Ivanov, I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, N.F. Osipov, V.A. Semin JINR, Dubna, Moscow Region, Russia
	Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The system based on four main elements - electrostatic deflector, focusing magnetic channel, Permanent Magnet Quadrupole lens and steering magnet is used in the DC140 cyclotron for extraction of the accelerated beam. The design and simulation of the beam extraction system from the DC140 cyclotron are presented in this report.
	Poster TUPAB190 [1.102 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB190
About •	paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 25 August 2021
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TUPAB206	Matching of Intense Beam in Six-Dimensional Phase Space	space-charge, emittance, focusing, framework	1897
	Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by US DOE under contract 89233218CNA000001 Beam matching is a common technique that is routinely employed in accelerator design to minimize beam losses. Despite being widely used, a full theoretical understanding of beam matching in 6D phase space remains elusive. Here, we present an analytical treatment of 6D beam matching of a high-intensity beam onto an RF structure. We begin our analysis within the framework of a linear model, and apply the averaging method to attain a matched solution for a set of 3D beam envelope equations. We then consider the nonlinear regime, where the beam size is comparable with the separatrix size. Starting with a Hamiltonian analysis in 6D phase space, we attain a self-consistent beam profile and show that it is significantly different from the commonly used ellipsoidal shape. Subsequently, we analyze the special case of equilibrium with equal space charge depression between all degrees of freedom. A comparison of beam dynamics for equipartitioned, equal space charge depression, and equal emittances beams is given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB206
About •	paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 24 August 2021
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TUPAB209	The Particle Tracking Code Fixfield	lattice, FFAG, acceleration, focusing	1905
	J.-B. Lagrange STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209
About •	paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021
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TUPAB215	Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment	network, lattice, focusing, operation	1920
	J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez HZB, Berlin, Germany
	With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215
About •	paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021
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TUPAB225	3D Magnetic Field Analysis of LHC Final Focus Quadrupoles with Beam Screen	octupole, focusing, HOM, database	1952
	T. Pugnat, B. Dalena, C. Lorin CEA-IRFU, Gif-sur-Yvette, France S. Bagnis CEA-DRF-IRFU, France
	During the LHC commissioning, a discrepancy in the non-linear corrector strengths between the model and the beam-based values has been observed. This has motivated the reconstruction of the 3D finite element model for the LHC final focusing MQXA type magnet. The longitudinal higher orders magnetic field pseudo-harmonics are computed taking into account ovalization of the magnet, interconnections design, and beam screens. The effect of this 3D field on the computation of the nonlinear correctors is evaluated and compared with beam-based corrector values. E. H. Maclean et al., "New approach to LHC optics commissioning for the nonlinear era", Phys. Rev. Acc. B, vol. 22, pp. 061004, June 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB225
About •	paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 12 August 2021
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TUPAB234	Exploring Accelerators for Intense Beams with the IBEX Paul Trap	octupole, lattice, experiment, simulation	1980
	J.A.D. Flowerdew University of Oxford, Oxford, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234
About •	paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 12 August 2021
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TUPAB237	Symplectic Tracking Through Field Maps	cavity, dipole, ion-source, radio-frequency	1992
	S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA B.T. Folsom, E. Laface, R. Miyamoto ESS, Lund, Sweden
	For many applications, it is necessary to track particles using field maps, instead of an analytic representation of the fields which is typically not available. These field maps come about while designing elements such as realistic magnets or radiofrequency cavities, and represent the field geometry on a mesh in space. However, simple interpolation of the fields from the field maps does not guarantee that the resulting tracking scheme satisfies the symplectic condition. Here we present a general method to decompose the field-map potential in the sum of interpolating functions that produces, by construction, a symplectic integrator.
	Poster TUPAB237 [0.307 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB237
About •	paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 22 August 2021
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TUPAB238	Algorithm to Analyze Complex Magnetic Structures Using a Tube Approach	multipole, HOM, octupole, sextupole	1995
	B. Riemann, M. Aiba PSI, Villigen PSI, Switzerland
	Modern synchrotron light sources often require sophisticated multipole field distributions that need to be realized by complex magnet structures. To pre-validate these magnet structures via simulations, the extraction procedure needs to output standard multipoles as well as fringe effects. The approach presented in this manuscript uses a volumetric grid map of the magnetic flux density as input. After computation of the reference trajectory (leapfrog integration), a large linear system is solved to compute transverse polynomial coefficients of the magnetic scalar potential in a series of interconnected thin cylinders (linear basis functions) along with that reference. The import of these coefficients into a lattice simulation is discussed using a modification of the tracking code Tracy. The shown approach is routinely used to check models of SLS 2.0 magnets for their properties.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB238
About •	paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021
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TUPAB308	Mechanical Consolidation of the LHC Inner Triplet Magnet Supporting System for Remote Alignment	alignment, vacuum, GUI, ECR	2207
	F. Micolon, N. Bourcey, J-B. Deschamps, A. Herty, S. Le Naour, T. Mikkola, V. Parma, D. Ramos, V. Rude, M. Sosin CERN, Meyrin, Switzerland
	Given the high radiation area and the tight alignment tolerances, the LHC inner triplet magnets were designed to be realigned remotely using motorized supporting jacks. However, during run 2 the LHC triplet realignment system started to show an unexpected behavior with erratic load variations on the magnet supporting jacks when operated. It was then decided to freeze any further realignment of the LHC triplet magnet for the remainder of the run. Subsequently, a project team was set up at CERN to understand better the conditions leading to such unexpected behavior and to study and propose a technical consolidation for the realignment system of the LHC triplet magnet. A fully instrumented magnet string using LHC triplet spare magnets was assembled and used at CERN to provide a realistic test bench for this study. This paper reports on the work undertaken to study the triplet magnet overall realignment kinematic, the findings on the readjustment system malfunction and details the consolidation solution implemented for the next LHC run
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB308
About •	paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 18 August 2021
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TUPAB313	Arrangement Optimization of Quadrupoles and Correctors for Beam Alignment	alignment, focusing, electron, FEL	2221
	L. Xu, Q.M. Zhang Xi’an Jiaotong University, People’s Republic of China H.X. Deng SARI-CAS, Pudong, Shanghai, People’s Republic of China N. Huang UCAS, Beijing, People’s Republic of China N. Huang SINAP, Shanghai, People’s Republic of China
	In the X-ray free-electron laser (XFEL), the alignment and stability of beam orbit have a great impact on power and qualities of the generated X-ray pulses. Currently, the beam-based alignment (BBA) is the most widely used technique in beam alignment. In order to find the best arrangement of quadrupoles and correctors, a mathematical model is established based on the transmission matrix method. With this model, several simple arrangements of quadrupoles and correctors are selected to simulate the beam alignment process. It is found that when two correctors adjust two quadrupoles, the beam can pass through the center of quadrupoles approximately collimated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB313

Paper

Title

Other Keywords

Page

MOPAB007

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

coupling, optics, 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.

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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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MOPAB008

Exploiting the Beam-Beam Wire Demonstrators in the Next LHC Run 3

octupole, luminosity, operation, experiment

65

A. Poyet
Université Grenoble Alpes, Grenoble, France
S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, A. Rossi, G. Sterbini
CERN, Geneva, Switzerland
K. Skoufaris
University of Crete, Heraklion, Crete, Greece

After the successful experiments performed during the LHC Run 2 with the Beam-Beam Wire demonstrators installed, on Beam 2, in the frame of the HL-LHC project, two of the four wire demonstrators were moved to Beam 1. The objective is to gain operational experience with the wire compensation also on that beam and therefore fully exploit the demonstrators’ potential. This paper proposes a numerical validation of the wire implementation using Run 3 scenarios and explores the optimization of those devices in that respect.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB008

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paper received ※ 17 May 2021 paper accepted ※ 24 May 2021 issue date ※ 11 August 2021

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MOPAB021

A Dispersive Quadrupole Scan Technique for Transverse Beam Characterization

SRF, emittance, optics, 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]

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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, optics, beam-losses, 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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MOPAB026

RHIC Delayed Abort Experiments

experiment, kicker, injection, dipole

126

M. Valette, D. Bruno, K.A. Drees, K.M. Hartmann, G. Heppner, K. Mernick, C. Mi, J.-L. Mi, R.J. Michnoff, J. Morris, F. Orsatti, E. Rydout, T. Samms, J. Sandberg, V. Schoefer, C. Schultheiss, T.C. Shrey, C. Theisen
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
For RHIC to operate at its top energy (100 GeV/n) while protecting the future sPHENIX detector, spontaneous and asynchronous firing of abort kicker modules (pre-fires) have to be avoided. A new triggering circuit for the abort kickers was implemented with relatively slow mechanical relays in series with the standard fast thyratron tubes. The relays prevents unwanted pre-fires during operation, but comes at the expense of a long latency - about 7 milliseconds - between the removal of beam permit and the actual firing of the abort kickers. Protection considerations of RHIC’s superconducting magnets forbid delaying energy extraction from the main dipoles and quadrupoles for too long after a quench. The beam has thus to circulate in both RHIc rings for a few milliseconds as the current in dipole and quadrupole circuit is being extracted. We present the results of delayed abort experiments conducted in July 2018 with the analysis of fast orbit and tune measurements and discuss the safety implications of this implementation for future RHIC operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB026

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paper received ※ 19 May 2021 paper accepted ※ 26 May 2021 issue date ※ 23 August 2021

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MOPAB035

Modified Lattice of the Compact Storage Ring in the cSTART Project at Karlsruhe Institute of Technology

sextupole, lattice, octupole, storage-ring

159

A.I. Papash, E. Bründermann, B. Härer, A.-S. Müller, R. Ruprecht, J. Schäfer, M. Schuh
KIT, Karlsruhe, Germany

A very large acceptance compact storage ring (VLA-cSR) is under design at the Institute for Beam Physics and Technology (IBPT) of the Karlsruhe Institute of Technology (KIT, Germany). The combination of a compact storage ring and a laser wakefield accelerator (LWFA) might be the basis for future compact light sources and advancing user facilities. Meanwhile, the post-LWFA beam should be adapted for storage and accumulation in a dedicated storage ring. Modified geometry and lattice of a VLA-cSR operating at 50 MeV energy range have been studied in detailed simulations. The main features of a new model are described here. The new design, based on 45° bending magnets, is suitable to store the post-LWFA beam with a wide momentum spread (1% to 2%) as well as ultra-short electron bunches in the fs range from the Ferninfrarot Linac- Und Test- Experiment (FLUTE). The DBA-FDF lattice with relaxed settings, split elements, and higher-order optics of tolerable strength allows improving the dynamic aperture to an acceptable level. This contribution discusses the lattice features in detail and different possible operation schemes of a VLA-cSR.

Poster MOPAB035 [1.405 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB035

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paper received ※ 10 May 2021 paper accepted ※ 27 May 2021 issue date ※ 24 August 2021

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MOPAB056

Optimization of a TBA with Stable Optics and Minimal Longitudinal Dispersion and CSR-Induced Emittance Growth

emittance, bunching, synchrotron, FEL

241

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)
In the beam transfer line which often consists of dipoles to deflect the beam trajectory, longitudinal dispersion effect and emission of coherent synchrotron radiation (CSR) will lead to beam phase space distortion, thus degrading the machine performance. In this study, optimizations of a triple-bend achromat (TBA) cell are conducted using the multi-objective particle swarm optimization (MOPSO) method to suppress the CSR-induced emittance growth and minimize the longitudinal dispersion functions up to high orders, simultaneously. For the longitudinal dispersion function, results of three optimization settings are reported, which makes the TBA design first-order, second-order, and higher-order isochronous. Furthermore, we study the shortest possible beamline length of the higher-order isochronous TBA design, which may pave the way to designing a more compact beam transfer line.

Poster MOPAB056 [0.366 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB056

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paper received ※ 12 May 2021 paper accepted ※ 28 May 2021 issue date ※ 15 August 2021

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MOPAB059

Tools for Use of Generalized Gradient Expansions in Accelerator Simulations

lattice, dipole, simulation, septum

253

M. Borland, R.R. Lindberg, R. Soliday, A. Xiao
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A common assumption in simulation of accelerators is that the magnets can be approximated using a hard-edge model, perhaps with some edge effects implemented in an impulse approximation. This is usually a good assumption but ignores details of the longitudinal variation of the magnetic fields, which makes it straightforward to implement symplectic tracking. Use of generalized gradient expansions* provides an alternative approach that can suppress numerical deficiencies that may be present in computed or measured 3D field maps. However, the computation of the expansions is not particularly straightforward. In this note, we describe several recently-developed tools that make this process fairly painless and allow tracking with such expansions in the program ELEGANT**. We show several examples of using the tools for simulations related to the Advanced Photon Source Upgrade.
* M. Venturini et al., NIM A 427, 387 (1999).
** M. Borland, Advanced Photon Source LS-287, September 2000

Poster MOPAB059 [4.311 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB059

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paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 18 August 2021

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MOPAB063

Commissioning Strategy for Diamond-II

MMI, lattice, optics, 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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MOPAB089

Effect of Different Models of Combined-function Dipoles on the HEPS Parameters

dipole, lattice, storage-ring, emittance

335

Y.Y. Guo, Y. Jiao, N. Li
IHEP, Beijing, People’s Republic of China

The high energy photon source (HEPS) is a 6 GeV, kilometer-scale storage ring light source being built in Beijing, China. In the current ring lattice, the combined-function dipoles are used and assumed to have constant dipole field. However, in the actual magnet design, an eccentrically placed quadrupole is adopted, in which the bending field along the trajectory is not constant. In this paper, we will present the effect of the two models of combined-function dipoles on the parameters of the storage ring.

Poster MOPAB089 [0.590 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB089

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paper received ※ 13 May 2021 paper accepted ※ 25 May 2021 issue date ※ 27 August 2021

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MOPAB101

Hollow and Flat Electron Beam Generation at FACET-II

electron, emittance, wakefield, experiment

376

A. Halavanau, S.J. Gessner, C.E. Mayes
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA

In this proceeding, we investigate hollow and flat electron beam generation at FACET-II facility. We focus on the case of a circular beamlet arrangement, also known as ’necklace’ beams. We study, via numerical simulations, the resulting e-beam dynamics in the FACET-II photoinjector, beam propagation through the high energy section, as well as possible experimental applications of the ’necklace’ beams. Finally, we evaluate the feasibility of high charge flat beam generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB101

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paper received ※ 23 May 2021 paper accepted ※ 27 July 2021 issue date ※ 23 August 2021

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MOPAB103

Study of Transverse Oscillation Coupling and Possibility of Its Minimization in SKIF (Novosibirsk)

coupling, emittance, sextupole, storage-ring

383

D. Leshenok
BINP, Novosibirsk, Russia
G.N. Baranov, E.B. Levichev, S.A. Nikitin
BINP SB RAS, Novosibirsk, Russia

The vertical emittance and, in general, the vertical beam size and angular divergence are of paramount importance in the SKIF (Russian acronym for Siberian Circular Photon Source) project developed in Novosibirsk. Therefore, a detailed simulation of the corresponding influence of possible errors in the storage ring was carried out with cross-validation by different methods. Variants of cross-coupling correction are proposed and modeled to obtain a vertical emittance of the order of one picometer simultaneously with minimizing vertical dispersion.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB103

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paper received ※ 18 May 2021 paper accepted ※ 17 August 2021 issue date ※ 19 August 2021

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MOPAB139

High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM

experiment, electron, focusing, target

485

G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas
RadiaBeam, Marina del Rey, California, USA
M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu
BNL, Upton, New York, USA
C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA

Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139

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paper received ※ 26 May 2021 paper accepted ※ 28 May 2021 issue date ※ 18 August 2021

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MOPAB151

A Stable Drive Beam for High Gradient Dielectric Wakefield Acceleration

focusing, wakefield, accelerating-gradient, acceleration

528

T.J. Overton, Y.M. Saveliev, G.X. Xia
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T.J. Overton, G.X. Xia
The University of Manchester, Manchester, United Kingdom
T.H. Pacey, Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Funding Council (STFC) student grant.
A high accelerating gradient, with stable beam transport, is necessary for the next generation of particle accelerators. Dielectric wakefield accelerators are a potential solution to this problem. In these proceedings, we present simulation studies of electron bunches in the self-wake regime inside a planar dielectric structure. This is analogous to driving beams in a dielectric wakefield accelerator. The transverse and longitudinal wake fields are investigated for dielectric plate gaps, various transverse beam sizes, and longitudinal bunch profiles. The effects of these on the stability of drive bunches, and acceleration of a witness bunch, are discussed in the context of electron bunches that can be produced with conventional linac RF technology.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB151

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paper received ※ 13 May 2021 paper accepted ※ 07 June 2021 issue date ※ 24 August 2021

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MOPAB164

Miniature, High Strength Transport Line Design for Laser Plasma Accelerator-Driven FELs

laser, electron, plasma, undulator

561

S. Fatehi, A. Bernhard, A.-S. Müller, M.S. Ning
KIT, Karlsruhe, Germany

Funding: This work is supported by the BMBF project 05K19VKA PlasmaFEL (Federal Ministry of Education and Research).
Laser-plasma acceleration is an outstanding candidate to drive the next-generation compact light sources and FELs. To compensate large chromatic effects using novel compact beam optic elements in the beam transport line is required. We aim at designing miniature, high strength, normal conducting and superconducting transport line magnets and optics for capturing and matching LPA-generated electron bunches to given applications. Our primary application case is a demonstration experiment for transverse gradient undulator (TGU) FELs, to be performed at the JETI laser facility, Jena, Germany. In this contribution, we present the current design of the beam transport line magnets and the beam optics calculations.
Laser Plasma Accelerators, FELs, Magnets, Beam Dynamics, Superconductivity, transverse gradient undulator

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB164

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paper received ※ 19 May 2021 paper accepted ※ 25 May 2021 issue date ※ 20 August 2021

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MOPAB179

Simulations of AGS Boosters Imperfection Resonances for Protons and Helions

resonance, proton, simulation, experiment

606

K. Hock, H. Huang, F. Méot, N. Tsoupas
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
As part of the effort to increase the polarization of the proton beam for the physics experiments at RHIC, a scan of orbit harmonic corrector strengths is performed in the Booster to ensure polarization transmission through the |G gamma|=3 and 4 imperfection resonances is optimized. These harmonic scans have been simulated using quadrupole alignment data and accurately match experimental data. The method used to simulate polarized protons is extended to polarized helions for crossing the |G gamma|=5 through |G gamma|=10 imperfection resonances and used to determine the corrector strength required to cross each resonance.

Poster MOPAB179 [0.437 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB179

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 02 September 2021

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MOPAB184

Unsupervised Learning Techniques for Tune Cleaning Measurement

ISOL, optics, coupling, luminosity

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]

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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

optics, 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

optics, 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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MOPAB195

Development of a Disk-and-Washer Cavity for the J-PARC Muon g-2/EDM Experiment

cavity, experiment, linac, coupling

658

Y. Takeuchi, J. Tojo
Kyushu University, Fukuoka, Japan
E. Cicek, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, T. Yamazaki, M. Yoshida
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R. Kitamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue, K. Sumi, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

At J-PARC, an experiment using muons accelerated by a linac is planned to measure the anomalous magnetic moment of muons and to search for the electric dipole moment. A 1296 MHz disk and washer (DAW) coupled cavity linac (CCL) is being developed for use in the middle beta section of the muon linac. The DAW CCL consists of 14 tanks with 11 cells each. All tanks are connected by bridge couplers and electromagnetic quadrupole doublets for focusing are installed in each bridge coupler. The basic design of the DAW cavity has already been completed, and now detailed cavity design studies and manufacturing process studies are underway. In this poster, we will report about these studies and the preparation status of manufacturing the DAW cavity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB195

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

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MOPAB196

Field tuning of the 1 MeV/n RFQ at KOMAC

rfq, ion-source, dipole, solenoid

662

H.-J. Kwon, Y.-S. Cho, J.J. Dang, W.-H. Jung, D.-H. Kim, H.S. Kim, K.H. Kim, S. Lee
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work was supported by the Korea Multi-purpose Accelerator Complex (KOMAC) operation funds through Ministry of Science and ICT (MIST) of Korean Government.
A 1 MeV/n Radio-frequency Quadrupole (RFQ) is under development at Korea Multi-purpose Accelerator Complex (KOMAC), the purposes of which are swift ion beam irradiation and compact neutron source. The RFQ was designed to accelerate ions with mass to charge (A/q) ratio up to 2.5. The designed peak current was 10 mA with 10% duty ratio. The RFQ is four vane structure resonated at 200 MHz. It has total 40 frequency tuners. There are no dipole rods and resonant coupling plate because the mode separation was large enough and the length of the RFQ was only two times of the wavelength. In this paper, the development status and field tuning results of the 1 MeV/n RFQ are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB196

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paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 20 August 2021

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MOPAB214

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

optics, 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.

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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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MOPAB220

Towards Deterministic Design of MBA-Lattices

dipole, lattice, emittance, sextupole

722

B.C. Kuske
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
Since the pioneering work of MAX IV *, multi-bend achromat (MBA) lattices have become the standard in lattice design for 4th generation lights sources as well as upgrades of 3rd generation storage rings. The distribution of the bending angle to many weak dipoles enables to reach unprecedented low emittance and highest brightness. In their most basic form, MBA-lattices consist of a repetitive unit cell and two identical matching cells on either end of the achromatic arc. The simplicity of both cells allows for a unique determination of the linear lattice parameters in dependence on boundary conditions defined by the design goals. Those might be the emittance, momentum compaction factor, chromaticity, as well as phase advances with respect to achieving higher-order achromatic structures. A scan of optional lattice prototypes is quickly obtained. We demonstrate this concept and apply it in the design of the first candidates for the lattice of BESSY III, a green-field 4th generation storage ring being currently planned at HZB, Berlin, Germany.
* https://www.maxiv.lu.se/accelerators-beamlines/accelerators/accelerator-documentation/max-iv-ddr/

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB220

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paper received ※ 17 May 2021 paper accepted ※ 23 July 2021 issue date ※ 26 August 2021

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MOPAB230

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

optics, luminosity, sextupole, 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, optics, alignment, simulation

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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MOPAB239

Simulation and Optimization of the Spin Coherence Time of Protons in a Prototype EDM Ring

storage-ring, dipole, simulation, polarization

771

M. Vitz, A. Lehrach
FZJ, Jülich, Germany
R. Shankar
INFN-Ferrara, Ferrara, Italy

The matter-antimatter asymmetry might be understood by investigating the EDM (Electric Dipole Moment) of elementary charged particles. A permanent EDM of a subatomic particle violates time-reversal and parity symmetry at the same time and would be, with the currently achievable experimental accuracy, a strong indication for physics beyond the Standard Model. The JEDI-Collaboration (Jülich Electric Dipole moment Investigations) in Jülich is preparing a direct EDM measurement for protons and deuterons: first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. A prototype EDM ring is an intermediate step before building the final storage ring to demonstrate sufficient beam lifetime and SCT (Spin Coherence Time) in a pure electrostatic ring as well as in a storage ring with combined electric and magnetic bending elements. In order to study the effect of E-B-deflectors on the orbit and the spin motion, the software library Bmad is used. The first results of the optics and spin simulations, with a focus on the optimization of the SCT, towards the prototype EDM ring will be discussed.

Poster MOPAB239 [0.560 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB239

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 23 August 2021

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MOPAB242

A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring

lattice, storage-ring, emittance, dipole

782

J. Li, M. Abo-Bakr, P. Goslawski
HZB, Berlin, Germany
Z.H. Bai
USTC/NSRL, Hefei, Anhui, People’s Republic of China

HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021

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MOPAB246

Design of the MEBT for the JAEA-ADS Project

MEBT, linac, emittance, rfq

790

B. Yee-Rendón, Y. Kondo, F.M. Maekawa, S.I. Meigo, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan

The Medium Energy Beam Transport (MEBT) will transport a CW proton beam with a current of 20 mA and energy of 2.5 MeV from the exit of the normal conducting Radiofrequency Quadrupole (RFQ) to the superconducting Half-Wave resonator (HWR) section. The MEBT must provide a good matching between the RFQ and HWR, effective control of the emittance growth and the halo formation, enough space for all the beam diagnostics devices, among others. This work reports the first lattice design and the beam dynamics studies for the MEBT of the JAEA-ADS.

Poster MOPAB246 [0.827 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB246

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paper received ※ 10 May 2021 paper accepted ※ 02 June 2021 issue date ※ 19 August 2021

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MOPAB253

Comparison of Transfer Map Derivation Methods for Static Magnetic Fields

multipole, lattice, extraction, operation

799

J.A. Crittenden, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation award numbers DMR-1829070 and PHY-1757811.
We compare methods for deriving transfer maps for static magnetic fields, including field-map tracking and tracking elements defined by multipole content. Building on prior work on quantitative evaluation of the accuracy of finite-element models used to produce field maps, we assess the tradeoffs between computing time and fidelity to the underlying magnetic field, including fringe fields, of the various approximate methods. We illustrate our approach using the example of electromagnets in the south arc of the 6-GeV Cornell High Energy Synchrotron Source, which have been operating since 2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB253

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 13 August 2021

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MOPAB254

Measurement of Horizontal Beam Size Using Sextupole Magnets

sextupole, storage-ring, positron, dipole

802

J.A. Crittenden, K.E. Deitrick, H.X. Duan, G.H. Hoffstaetter, V. Khachatryan, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by National Science Foundation award number DMR-1829070.
The quadratic dependence of sextupole fields on position results in a beam-size-dependent kick on a beam traversing a sextupole magnet. A change in sextupole strength changes the closed orbit and the tune of the beam in a storage ring. Measuring both therefore allows conclusions about the beam size in the sextupole. Here we derive the pertinent formula and discuss the applicability to storage rings. In particular we investigate the measurement accuracy that can be achieved at the Cornell High Energy Synchrotron Source. The Cornell Electron-positron Storage Ring underwent a major upgrade in 2018 with the goal of reducing the emittance by a factor of four. A variety of beam size measurement methods have been developed to monitor the positron beam size, including visible synchrotron light and interferometry. We investigate the sensitivity of the sextupole method and compare to other measurement techniques. The design horizontal emittance of the 6-GeV positron beam is about 30 nm-rad with typical beam sizes of about 1 mm, setting the scale for the required accuracy in the beam-size measurement.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB254

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 01 September 2021

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MOPAB260

Optics Corrections with LOCO on Sirius Storage Ring

optics, 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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MOPAB261

NSLS-II Storage Ring Lattice Analysis using Response Matrices

lattice, alignment, storage-ring, sextupole

829

J. Choi
BNL, Upton, New York, USA

Funding: Work supported by the U.S. Department of Energy (DOE) under contract No. DE-SC0012704.
Affected from various sources, the NSLS-II storage ring lattice is slightly changing operation to operation and, for the operational performance, we are continually optimizing the lattice and maintaining the response matrices for the feedback and lattice analysis. Because not all sources are identified, we are investing efforts to identify as many as possible. As one of such efforts, we also study the measured response matrices. In this paper, we present the results of lattice studies using a pair of recently measured response matrices.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB261

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

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MOPAB264

Commissioning of the DESIR High-Resolution Separator at CENBG

emittance, multipole, MMI, dipole

841

J. Michaud, P. Alfaurt, A. Balana, B. Blank, L. Daudin, T. Kurtukian-Nieto, S. Leblanc, L.S. Serani
CENBG, Gradignan, France
F. Méot
BNL, Upton, New York, USA
F. Varenne
GANIL, Caen, France

DESIR is the low-energy part of the SPIRAL2 ISOL facility under construction at GANIL. The high-resolution mass separator (HRS) included in DESIR is a 180 degree symmetric online separator with two 90 degree magnetic dipole sections arranged with electrostatic quadrupoles, sextupoles and a multipole on the mid plane. The HRS is now completely mounted at CENBG and under commissioning for the next 2 to 3 years before its transfer at the entrance of the DESIR facility. The objective is to test, characterise and correct all HRS elements contributing to the higher order aberration by performing experimental measurements and comparing them with the results from different simulation tools. The recently mounted pepperpot-type emittance-meter will allow us to observe the emittance figures and dynamically tune the multipole to improve the optical parameters of the HRS. We will present the first results concerning the hexapolar correction with the multipole, the associated emittance measurements and the resolution currently achieved.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB264

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paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 10 August 2021

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MOPAB269

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

extraction, dipole, optics, 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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MOPAB277

Installation, Use and Follow-Up of an Emittance-Meter at the Arronax Cyclotron 70XP

emittance, cyclotron, injection, ECR

877

F. Poirier, R. Bellamy, F. Bulteau-Harel, C. Castel, T. Durand, X. Goiziou, F. Haddad, C. Koumeir, R. Lelièvre, G. Mechin, L. Perrigaud, J. Poudevigne, H. Trichet
Cyclotron ARRONAX, Saint-Herblain, France
T. Adam, P.G. Graehling, M. Heine, C. Maazouzi, F.R. Osswald, E.K. Traykov
IPHC, Strasbourg Cedex 2, France
A. Dinkov, S. Wurth
IJCLab, ORSAY, France
F. Haddad
SUBATECH, Nantes, France

Funding: This work is supported by grants from the ANR program "Investissements d’Avenir", n°ANR-11-EQPX-0004, n°ANR-11-LABX-18-01 and n°ANR-16-IDE-0007 and by a PhD scholarship from CNRS/IN2P3.
The 70 MeV cyclotron group of the Arronax GIP (Interest Public Group), France, foresees to increase its beam intensity on target. For this, several beam studies are being performed in the various sections of the accelerator including the injection. Thus, an Allison-type emittance-meter has been installed in this section above the cyclotron and downstream a quadrupole triplet. Installation and the first results of a campaign of measurements are presented including high intensity runs, up to 1 mA for 40 keV H⁻ ions. The emittance-meter is expected to be used with several accelerators throughout the world. Therefore, a strategy on the follow-up of the activation of sample materials used in the equipment is being established and is described in the paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB277

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paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 12 August 2021

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MOPAB295

Simulation Study of Emittance Measurement Using a Genetic Algorithm for Space Charge Dominated Beams

emittance, space-charge, simulation, lattice

935

H.D. Zhang, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 under and the STFC Cockcroft core grant No. ST/G008248/1.
The quadrupole scan method is one of the traditional ways to measure beam emittance in an accelerator. The required devices are simple: several quadrupole magnets and a beam profile monitor. Beam sizes are measured from the beam profile monitor with different quadrupole settings to bring the beam through its waist and then fitted to a quadratic equation to determine the Twiss parameters. measured data from a quadrupole scan taking the beam through its waist is fitted to a quadratic equation and this allows determining the Twiss parameters. However, with increasing beam intensity, the transfer function becomes non-linear and this causes a deviation of the fitted emittance from its real value, making it no longer useful. In this contribution, a genetic algorithm is applied to find the optimum quadrupole scan fit in space-charge dominated electron beams. Results from simulations using different space charge levels are presented and scenarios identified where this method can be applied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB295

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

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MOPAB302

Characterization of the Full Transverse Phase Space of Electron Bunches at ARES

simulation, experiment, electron, linac

952

S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, H. Dinter, W. Kuropka, F. Mayet, T. Vinatier
DESY, Hamburg, Germany
R.W. Aßmann
INFN/LNF, Frascati, Italy
S. Jaster-Merz
University of Hamburg, Hamburg, Germany

The ARES linear accelerator at the SINBAD facility (DESY) is dedicated to perform accelerator R&D studies with sub-fs short electron bunches to test novel acceleration techniques and diagnostics devices. Currently, the commissioning of the linac is ongoing and first experiments are being performed. For this, the knowledge of the full phase space of the particle beams is of high interest to, for example, optimize the accelerator performance and identify possible errors in the beam line. Tomographic methods can be used to gain insight into the full 4D transverse phase space and its correlations. Here, simulation results and first experimental preparations of a 4D transverse phase-space tomography of electron bunches at ARES are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB302

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paper received ※ 17 May 2021 paper accepted ※ 16 June 2021 issue date ※ 30 August 2021

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MOPAB304

Beam Diagnostics for Multi-Objective Bayesian Optimization at the Argonne Wakefield Accelerator Facility

emittance, diagnostics, dipole, wakefield

960

J.P. Gonzalez-Aguilera, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
W. Liu, P. Piot, J.G. Power, E.E. Wisniewski
ANL, Lemont, Illinois, USA
R.J. Roussel
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA

Particle accelerators must achieve certain beam quality objectives for use in different experiments. Usually, optimizing certain beam objectives comes at the expense of others. Additionally, there are many input parameters and a limited number of diagnostics. Therefore, accelerator tuning becomes a multi-objective optimization problem with a limited number of observations. Multi-objective Bayesian optimization was recently proposed as an efficient method to find the Pareto front for an online accelerator tuning problem with reduced number of observations. In order to experimentally test the multi-objective Bayesian optimization method, a novel accelerator diagnostic is being designed to measure multiple beam quality metrics of an electron beam at the Argonne Wakefield Accelerator Facility. Here, we present a design consisting in a pepper-pot mask, a dipole magnet and a scintillation screen, which allows a simultaneous measurement of the electron beam energy spread and vertical emittance. Additionally, a surrogate model for the vertical emittance was constructed with only 60 observations and without prior knowledge of the objective function nor diagnostics constraints.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB304

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paper received ※ 18 May 2021 paper accepted ※ 08 June 2021 issue date ※ 26 August 2021

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MOPAB353

Design of a compact Ka-Band Mode Launcher for High-gradient Accelerators

cavity, coupling, simulation, accelerating-gradient

1100

G. Torrisi, G.S. Mauro, G. Sorbello
INFN/LNS, Catania, Italy
M. Behtouei, L. Faillace, B. Spataro, A. Variola
INFN/LNF, Frascati, Italy
V.A. Dolgashev
SLAC, Menlo Park, California, USA
L. Faillace, M. Migliorati
Sapienza University of Rome, Rome, Italy
M. Migliorati
INFN-Roma1, Rome, Italy
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
G. Sorbello
University of Catania, Catania, Italy

In this work, we present the RF design of a table-top Ka-Band mode launcher operating at 35.98 GHz. The structure consists of a symmetrical 4-port WR28 rectangular-TE10-to-circular-TM01 mode converter that is used to couple a peak output RF power of 5 MW (pulse length up to 50 ns and repetition rate up to 100 Hz) in Ka-Band linear accelerator able to achieve very high accelerating gradients (up to 200 MV/m). Numerical simulations have been carried out with the 3D full-wave commercial simulator Ansys HFSS in order to obtain a preliminary tuning of the accelerating field flatness at the operating frequency f0=35.98 GHz. The main RF parameters, such as reflection coefficient, transmission losses, and conversion efficiency are given together with a verification of the field azimuthal symmetry which avoids dipole and quadrupole deflecting modes. To simplify future manufacturing, reduce fabrication costs, and also reduce the probability of RF breakdown, the proposed new geometry has "open" configuration. This geometry eliminates the flow of RF currents through critical joints and allows this device to be milled from metal blocks.

Poster MOPAB353 [3.131 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB353

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paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 27 August 2021

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MOPAB374

Creating Exact Multipolar Fields in Accelerating RF Cavities via an Azimuthally Modulated Design

cavity, simulation, dipole, collider

1154

L.M. Wroe, S.L. Sheehy
JAI, Oxford, United Kingdom
R. Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
M. Dosanjh
CERN, Meyrin, Switzerland
S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

In this paper, we present a novel method for designing RF structures with specifically tailored multipolar field contributions. This has a range of applications, including the suppression of unwanted multipolar fields or the introduction of wanted terms, such as for quadrupole focusing. In this article, we outline the general design methodology and compare the expected results to 3D CST simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB374

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paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 23 August 2021

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MOPAB376

Design and Fabrication of a Quadrupole Resonator for SRF R&D

SRF, cavity, niobium, radio-frequency

1158

R. Monroy-Villa, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
S. Gorgi Zadeh, P. Putek
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
R. Monroy-Villa, D. Reschke, J.H. Thie
DESY, Hamburg, Germany

As Nb superconducting radio-frequency (SRF) cavities are now approaching the theoretical limits of the material, a variety of different surface treatments have been developed to further improve their performance; although no fully understood theory is yet available. Small superconducting samples are studied to characterize their material properties and their evolution under different surface treatments. To study the RF properties of such samples under realistic SRF conditions at low temperatures, a test cavity called quadrupole resonator (QPR) is currently being fabricated. In this work we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB and its design will allow for testing samples under cavity-like conditions, i.e., at temperatures between 2K and 8 K, under magnetic fields up to 120mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with a status report on the current manufacturing process, will be presented.

Poster MOPAB376 [1.119 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB376

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paper received ※ 26 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021

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TUXC07

Modified Halbach Magnets for Emerging Accelerator Applications

permanent-magnet, dipole, collider, electron

1315

S.J. Brooks
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The original circular Halbach magnet design creates a strong pure multipole field from permanent magnet pieces without intervening iron. This design has been extended recently at the CBETA 4-turn ERL, whose return loop includes combined-function (dipole+quadrupole) Halbach-derived magnets, plus a modular system of tuning shims to improve all 216 magnets’ relative field accuracy to better than 10^-3. This paper describes further modifications of the Halbach design enable a larger range of accelerator applications in the future: (1) open-midplane designs to allow synchrotron radiation in light sources and other high-energy electron rings, ERLs or RLAs to escape. (2) Quadrupole magnets with an oval aperture allow larger gradients than a circular aperture, provided the beam is more extended in one axis than the other, as usual for a quadrupole in a focussing system. These can be used in compact hadron therapy gantries. (3) New collider complexes often require multiple rings for acceleration or top-up, accumulation, collision and cooling. Multi-aperture permanent magnets are possible to cheaply and compactly build ring systems with several stable orbits separated by a few cm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC07

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paper received ※ 14 May 2021 paper accepted ※ 08 July 2021 issue date ※ 23 August 2021

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TUPAB005

Emittance Estimates for the Future Circular Collider

emittance, alignment, simulation, sextupole

1338

L. van Riesen-Haupt, T.K. Charles, R. Tomás García, F. Zimmermann
CERN, Meyrin, Switzerland
T.K. Charles
The University of Liverpool, Liverpool, United Kingdom

The alignment strategy of the FCC-ee has a large impact on its luminosity. Larger alignment tolerances result in increased coupling and a subsequently higher vertical emittance. At the same time, tighter alignment tolerances around the 100 km ring are a major cost driver. This paper applies analytical emittance estimate methods to the FCC-ee and compares their predictions to data from simulations with different alignment tolerances. These methods can be used to help understand the impact of misalignments of certain magnet groups and to come up with an efficient alignment strategy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB005

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paper received ※ 16 May 2021 paper accepted ※ 14 June 2021 issue date ※ 26 August 2021

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TUPAB006

The Impact of Beam Position Monitor Tilts on Coupling Measurements

coupling, resonance, optics, simulation

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, emittance, alignment, optics

1346

B. Wang, Y. Wang, Y. Wei, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

This paper describes the error correction scheme for the CEPC CDR lattice in Higgs mode, which has a small beta function at the interaction point. The low emittance optics has an enhanced sensitivity to the magnet misalignments and field errors, especially for the final focus quadrupole misalignment. The magnet imperfection will cause the closed orbit distortion and optics distortion. The correction scheme for these magnet imperfections includes the closed orbit correction, the dispersion correction, the beta function correction and the betatron coupling correction. The resulting performance and the dynamic aperture for the corrected lattice are studied.

Poster TUPAB007 [1.075 MB]

DOI •

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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TUPAB008

Progress of the First-Turn Commissioning Simulations for HEPS

simulation, lattice, MMI, dipole

1349

B. Wang, Z. Duan, D. Ji, Y. Jiao, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is 6 GeV, kilometer-scale, 4th generation storage ring light source. The lattice has an ultralow emittance and strong focusing such that the beam dynamics is very sensitive to the magnet misalignments and other error sources. Getting the first turn and establishing the closed orbit is essential for accelerator commissioning. This paper describes a simulation algorithm for achieving the first turn commission based on the latest HEPS storage ring lattice. We developed a new accelerator toolbox (AT)-based program for automatic optimizing the first turn commissioning. The algorithm and simulation results will be presented in this paper.

Poster TUPAB008 [0.646 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB008

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paper received ※ 14 May 2021 paper accepted ※ 11 June 2021 issue date ※ 28 August 2021

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TUPAB010

Impact of Bunch Current on Optics Measurements in SuperKEKB

optics, damping, impedance, 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

optics, 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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TUPAB016

ESS RFQ: Installation and Tuning at Lund

rfq, insertion, coupling, cavity

1372

P. Hamel, D. Chirpaz-Cerbat, M. Desmons, A.C. France, O. Piquet
CEA-IRFU, Gif-sur-Yvette, France
A. Dubois, Y. Le Noa
CEA-DRF-IRFU, France

The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) has been delivered by the end of 2019. It has been provided by CEA, IRFU, Saclay/France. It consists of five sections with a total length of 4.6 m and accelerates the 70 mA proton beam from 75 keV up to 3.6 MeV. It will be fed with 900 kW peak power through two coaxial loop couplers. The installation process (alignment, vacuum test), as well as the tuning process based on bead-pull measurements, is presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB016

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paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 14 August 2021

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TUPAB017

Study of Conduction-Cooled Superconducting Quadrupole Magnets Combined with Dipole Correctors for the ILC Main Linac

dipole, linac, SRF, cavity

1375

Y. Arimoto, S. Michizono, Y. Morikawa, N. Ohuchi, T. Oki, H. Shimizu, K. Umemori, X. Wang, A. Yamamoto, Y. Yamamoto, Z.G. Zong
KEK, Ibaraki, Japan
V.S. Kashikhin
Fermilab, Batavia, Illinois, USA

A superconducting rf (SRF) cryomodule for International Linear Collider(ILC) Main Linac equips focus/steering magnets. The magnets are "superferric" magnets with four superconducting (SC) race track coils conductively cooled from the cryomodule LHe supply pipe. The quadrupole field gradient and dipole field are 40 T/m and 0.1 T, respectively. The magnet length and iron-pole radius are 1 m and 0.045 m, respectively. It is known that dark current is generated at SRF cavities and accelerated through the following linac string. The dark current reaches and heats the SC magnets. It is estimated that the power deposition in the magnet may reach more than a few watts and temperature of the SC coils may locally reach to critical temperature of NbTi. It is important to make the magnet not reach quench with sufficient conduction cooling. We aim to realize the SC magnet which can stably operate under such condition. We plan to develop test coils made of three types of SC materials, NbTi, Nb₃Sn, and MgB₂ and study thermal characteristics and stability . We will develop a short model magnet, based on the test coil results. Here, we will present the magnet design study and the R&D plan.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB017

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paper received ※ 19 May 2021 paper accepted ※ 16 June 2021 issue date ※ 18 August 2021

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TUPAB059

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

betatron, storage-ring, optics, 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

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

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TUPAB083

Dual Energies in the LCLS Copper Linac

linac, feedback, klystron, betatron

1570

F.-J. Decker, C. Bianchini Mattison, D.K. Bohler, A. Brachmann, W.S. Colocho, S. Condamoor, M.L. Gibbs, K.H. Kim, A.A. Lutman, T.J. Maxwell, J.A. Mock, H.-D. Nuhn, J.C. Sheppard, H. Smith, T.J. Smith, M. Stanek, S. Zelazny, Z. Zhang, C.M. Zimmer
SLAC, Menlo Park, California, USA

For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the superconducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.

Poster TUPAB083 [0.479 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB083

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paper received ※ 19 May 2021 paper accepted ※ 27 May 2021 issue date ※ 21 August 2021

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TUPAB094

Multi-Start Foil Wound Solenoids for Multipole Suppression

solenoid, multipole, emittance, simulation

1596

N. Majernik, A. Fukasawa, J.B. Rosenzweig, A. Suraj
UCLA, Los Angeles, California, USA

Funding: National Science Foundation Grant No. PHY-1549132 - CBB, DE-SC0020409
Solenoids for beam transport are typically wound helically, with each layer of wire being laid down on top of the previous, or as "pancakes" where the wire is wound radially in before crossing over and winding out. Both of these approaches break rotational symmetry and introduce higher-order multipole moments which can be deleterious to beam emittance. For high brightness beams, this can be particularly problematic. To this end, a solenoid employing multi-start foil windings is simulated and compared to conventional choices. With appropriate design, this approach can forbid certain multipoles by symmetry.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB094

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paper received ※ 19 May 2021 paper accepted ※ 20 July 2021 issue date ※ 15 August 2021

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TUPAB102

A New 2nd Bunch Compression Chicane for the FLASH2020+ Project

dipole, vacuum, focusing, FEL

1618

M. Vogt, J. Zemella
DESY, Hamburg, Germany

The first stage of the FLASH2020+ project is an upgrade of the FLASH injector beamline. Within this framework, the 2nd bunch compression chicane (BCC) will be completely redesigned. The old S-chicane will be replaced with a new C-chicane which is 3.5m shorter thereby generating space a new section for re-matching the beam from the injector into the linac. The new BCC will be equipped with quad/skew-quad units in both legs of the chicane to compensate correlations of the transverse degrees of freedom with the longitudinal ones. Since quadrupoles tend to have a circular bore, the chicane is designed with movable round vacuum chambers and movable dipoles for maintaining full flexibility in choosing the compression parameters. This article describes the technical details and introduces a thin-lens model of BCCs which allows analytical estimates on the effects of powering the quad/skew-quad units on optics parameters as well as estimates on the required strengths of these magnets in order to remove correlations of the magnitudes typically observed at FLASH.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB102

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paper received ※ 19 May 2021 paper accepted ※ 14 June 2021 issue date ※ 29 August 2021

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TUPAB104

Redesign of the FLASH2 Post-SASE Undulator Beamline

undulator, electron, photon, MMI

1626

F. Christie, J. Rönsch-Schulenburg, S. Schreiber, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is one of the two SASE (Self-Amplified Spontaneous Emission) undulator beamlines lines comprising variable gap undulators to produce radiation in the XUV and soft X-ray regime at FLASH. Downstream of the SASE undulators the beamline is currently undergoing a major redesign. During shutdowns in summer 2020 and winter 2021 two PolariX TDSs (Polarizable X-band Transverse Deflecting Structure) were installed, as well as additional diagnostics, to monitor the longitudinal phase space density of the electron bunches. Additionally, an afterburner undulator will be integrated in the next shutdown to produce circularly polarized light with wavelengths down to 1.39 nm. In this paper, we will present the modifications that were and will be made to the electron beamline in the course of this redesign.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB104

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 23 August 2021

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TUPAB129

Beam Based Alignment in a Compact THz-FEL Facility

FEL, alignment, linac, undulator

1692

Q.S. Chen, T. Hu, K.F. Liu, B. Qin, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China

In this paper, we presented the beam based alignment results in a compact THz-FEL facility. The alignment was divided into two sections, the transport line and the optical line. In the transport line, all the five quadrupoles upstream of the undulator were adjusted one by one to fit the electron beam from the traveling wave linac. In the optical line, a set of auxiliary coils were winded on the yokes of the quadrupole downstream of the double bend achromat (DBA) to produce a vertical steering force. Another combined steering magnet, together with the auxiliary coils, corrected the beam orbit in the optical line. With the dispersion free test, the displacement between the magnetic centers of the quads and the beam orbit was less than 0.1mm.

Poster TUPAB129 [0.673 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB129

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021

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TUPAB134

Linac-to-Booster Optimization Procedure Towards High Transmission for the Alba Injector

linac, booster, alignment, operation

1703

R. Muñoz Horta, D. Lanaia, E. Marín, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a third generation synchrotron light source that consists of 3 accelerators (Linac, Booster and Storage ring) and two transfer lines, Linac-to-Booster (LTB) and Booster-to-Storage (BTS). The ALBA accelerators team has defined a robust procedure that optimizes the beam performance from Linac to Booster in terms of transmission and stability. The implemented beam-based alignment and global orbit correction techniques have been investigated first in simulations and afterwards successfully implemented in the machine.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB134

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paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 16 August 2021

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TUPAB172

Quadrupole Magnet Design for a Heavy-Ion IH-DTL

heavy-ion, DTL, proton, linac

1793

P.F. Ma, C.T. Du, X. Guan, M.W. Wang, X.W. Wang, Y.L. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People’s Republic of China
W. Chen, W.L. Liu, W. Lv, M.T. Qiu, B.C. Wang, D. Wang, M.C. Wang, Z.M. Wang, Y.H. Yan, M.T. Zhao
NINT, Xi’an, People’s Republic of China

Xi’an Proton Application Facility (XiPAF) will be upgraded to provide heavy-ion beams with a heavy-ion injector. The injector consists of an ECR heavy-ion source, a Low Energy Beam Transport line (LEBT), a Radio Frequency Quadrupole (RFQ), an Interdigital H-mode Drift Tube Linac (IH-DTL), and a Linac to Ring Beam Transport line (LRBT). The IH-DTL can accelerate the ions with mass to charge up to 6.5 from 0.4 MeV/u to 2 MeV/u. To provide transverse focusing, the electro-magnetic quadrupoles are installed inside the drift tubes of IH-DTL, thus the magnet needs to be high-gradient and compact. This paper gives the quadrupole magnet design for the heavy-ion IH-DTL. The results show that the quadrupole magnet design can meet the requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB172

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paper received ※ 08 May 2021 paper accepted ※ 21 June 2021 issue date ※ 23 August 2021

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TUPAB189

Design and Simulation of Beam Transport Lines of DC140 Cyclotron

cyclotron, radiation, target, heavy-ion

1845

V.I. Lisov, N.S. Kirilkin, A.S. Zabanov
JINR/FLNR, Moscow region, Russia
I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, V.A. Semin
JINR, Dubna, Moscow Region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The beam transport system has three lines: for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The design and simulation of the beam transport system from cyclotron is presented in this report. The beam focusing in the beam lines is provided by set of quadrupole lenses. The beam diagnostics system consists of the Faraday caps, luminophores and the magnetic scanning system.

Poster TUPAB189 [0.958 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB189

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paper received ※ 14 May 2021 paper accepted ※ 02 June 2021 issue date ※ 17 August 2021

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TUPAB190

Design and Simulation of the Extraction System of DC140 Cyclotron

extraction, cyclotron, focusing, septum

1849

V.I. Lisov, A.A. Protasov, A.S. Zabanov
JINR/FLNR, Moscow region, Russia
K. Gikal, G.G. Gulbekyan, I.A. Ivanenko, G.N. Ivanov, I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, N.F. Osipov, V.A. Semin
JINR, Dubna, Moscow Region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The system based on four main elements - electrostatic deflector, focusing magnetic channel, Permanent Magnet Quadrupole lens and steering magnet is used in the DC140 cyclotron for extraction of the accelerated beam. The design and simulation of the beam extraction system from the DC140 cyclotron are presented in this report.

Poster TUPAB190 [1.102 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB190

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 25 August 2021

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TUPAB206

Matching of Intense Beam in Six-Dimensional Phase Space

space-charge, emittance, focusing, framework

1897

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract 89233218CNA000001
Beam matching is a common technique that is routinely employed in accelerator design to minimize beam losses. Despite being widely used, a full theoretical understanding of beam matching in 6D phase space remains elusive. Here, we present an analytical treatment of 6D beam matching of a high-intensity beam onto an RF structure. We begin our analysis within the framework of a linear model, and apply the averaging method to attain a matched solution for a set of 3D beam envelope equations. We then consider the nonlinear regime, where the beam size is comparable with the separatrix size. Starting with a Hamiltonian analysis in 6D phase space, we attain a self-consistent beam profile and show that it is significantly different from the commonly used ellipsoidal shape. Subsequently, we analyze the special case of equilibrium with equal space charge depression between all degrees of freedom. A comparison of beam dynamics for equipartitioned, equal space charge depression, and equal emittances beams is given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB206

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paper received ※ 14 May 2021 paper accepted ※ 28 May 2021 issue date ※ 24 August 2021

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TUPAB209

The Particle Tracking Code Fixfield

lattice, FFAG, acceleration, focusing

1905

J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209

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paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021

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TUPAB215

Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment

network, lattice, focusing, operation

1920

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
HZB, Berlin, Germany

With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215

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paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021

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TUPAB225

3D Magnetic Field Analysis of LHC Final Focus Quadrupoles with Beam Screen

octupole, focusing, HOM, database

1952

T. Pugnat, B. Dalena, C. Lorin
CEA-IRFU, Gif-sur-Yvette, France
S. Bagnis
CEA-DRF-IRFU, France

During the LHC commissioning, a discrepancy in the non-linear corrector strengths between the model and the beam-based values has been observed*. This has motivated the reconstruction of the 3D finite element model for the LHC final focusing MQXA type magnet. The longitudinal higher orders magnetic field pseudo-harmonics are computed taking into account ovalization of the magnet, interconnections design, and beam screens. The effect of this 3D field on the computation of the nonlinear correctors is evaluated and compared with beam-based corrector values.
*E. H. Maclean et al., "New approach to LHC optics commissioning for the nonlinear era", Phys. Rev. Acc. B, vol. 22, pp. 061004, June 2019.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB225

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paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 12 August 2021

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TUPAB234

Exploring Accelerators for Intense Beams with the IBEX Paul Trap

octupole, lattice, experiment, simulation

1980

J.A.D. Flowerdew
University of Oxford, Oxford, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 12 August 2021

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TUPAB237

Symplectic Tracking Through Field Maps

cavity, dipole, ion-source, radio-frequency

1992

S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
B.T. Folsom, E. Laface, R. Miyamoto
ESS, Lund, Sweden

For many applications, it is necessary to track particles using field maps, instead of an analytic representation of the fields which is typically not available. These field maps come about while designing elements such as realistic magnets or radiofrequency cavities, and represent the field geometry on a mesh in space. However, simple interpolation of the fields from the field maps does not guarantee that the resulting tracking scheme satisfies the symplectic condition. Here we present a general method to decompose the field-map potential in the sum of interpolating functions that produces, by construction, a symplectic integrator.

Poster TUPAB237 [0.307 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB237

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 22 August 2021

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TUPAB238

Algorithm to Analyze Complex Magnetic Structures Using a Tube Approach

multipole, HOM, octupole, sextupole

1995

B. Riemann, M. Aiba
PSI, Villigen PSI, Switzerland

Modern synchrotron light sources often require sophisticated multipole field distributions that need to be realized by complex magnet structures. To pre-validate these magnet structures via simulations, the extraction procedure needs to output standard multipoles as well as fringe effects. The approach presented in this manuscript uses a volumetric grid map of the magnetic flux density as input. After computation of the reference trajectory (leapfrog integration), a large linear system is solved to compute transverse polynomial coefficients of the magnetic scalar potential in a series of interconnected thin cylinders (linear basis functions) along with that reference. The import of these coefficients into a lattice simulation is discussed using a modification of the tracking code Tracy. The shown approach is routinely used to check models of SLS 2.0 magnets for their properties.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB238

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paper received ※ 18 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021

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TUPAB308

Mechanical Consolidation of the LHC Inner Triplet Magnet Supporting System for Remote Alignment

alignment, vacuum, GUI, ECR

2207

F. Micolon, N. Bourcey, J-B. Deschamps, A. Herty, S. Le Naour, T. Mikkola, V. Parma, D. Ramos, V. Rude, M. Sosin
CERN, Meyrin, Switzerland

Given the high radiation area and the tight alignment tolerances, the LHC inner triplet magnets were designed to be realigned remotely using motorized supporting jacks. However, during run 2 the LHC triplet realignment system started to show an unexpected behavior with erratic load variations on the magnet supporting jacks when operated. It was then decided to freeze any further realignment of the LHC triplet magnet for the remainder of the run. Subsequently, a project team was set up at CERN to understand better the conditions leading to such unexpected behavior and to study and propose a technical consolidation for the realignment system of the LHC triplet magnet. A fully instrumented magnet string using LHC triplet spare magnets was assembled and used at CERN to provide a realistic test bench for this study. This paper reports on the work undertaken to study the triplet magnet overall realignment kinematic, the findings on the readjustment system malfunction and details the consolidation solution implemented for the next LHC run

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB308

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paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 18 August 2021

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TUPAB313

Arrangement Optimization of Quadrupoles and Correctors for Beam Alignment

alignment, focusing, electron, FEL

2221

L. Xu, Q.M. Zhang
Xi’an Jiaotong University, People’s Republic of China
H.X. Deng
SARI-CAS, Pudong, Shanghai, People’s Republic of China
N. Huang
UCAS, Beijing, People’s Republic of China
N. Huang
SINAP, Shanghai, People’s Republic of China

In the X-ray free-electron laser (XFEL), the alignment and stability of beam orbit have a great impact on power and qualities of the generated X-ray pulses. Currently, the beam-based alignment (BBA) is the most widely used technique in beam alignment. In order to find the best arrangement of quadrupoles and correctors, a mathematical model is established based on the transmission matrix method. With this model, several simple arrangements of quadrupoles and correctors are selected to simulate the beam alignment process. It is found that when two correctors adjust two quadrupoles, the beam can pass through the center of quadrupoles approximately collimated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB313

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paper received ※ 16 May 2021 paper accepted ※ 31 August 2021 issue date ※ 16 August 2021

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TUPAB365

Demonstration of ‘ZEPTO’ Permanent Magnet Technology on Diamond Light Source

permanent-magnet, vacuum, lattice, radiation

2370

A.R. Bainbridge, B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Krumpa
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
I.P.S. Martin, W. Tizzano
DLS, Oxfordshire, United Kingdom

The use of permanent magnets (PM’s) in place of traditional electromagnets is becoming more common in accelerator systems around the world. This change is being driven by the desire to reduce both the energy costs and carbon footprint of accelerators. However, the problem remains that it is difficult to adjust the field strength of PM systems. STFC and CERN have a longstanding collaboration in the Zero-Power Tuneable Optics (ZEPTO) project which aims to develop PM systems that are tuneable via moving the PM blocks within a static pole structure. This collaboration has previously produced 3 prototype magnets (2 quadrupoles and 1 dipole) for the proposed CLIC accelerator and aims to expand suitability to a variety of accelerators. We are now demonstrating this technology on a real machine by installing a ZEPTO magnet on Diamond Light Source. We outline the design, construction, and improvement of this technology demonstrator, highlighting the innovations over previous generations of ZEPTO technology that account for previously observed drawbacks.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB365

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paper received ※ 18 May 2021 paper accepted ※ 22 June 2021 issue date ※ 12 August 2021

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TUPAB369

A Fast Non-Linear Model for the EBS Combined Sextupole-Corrector Magnets

sextupole, SRF, dipole, multipole

2381

G. Le Bec
ESRF, Grenoble, France

Corrector are often integrated in higher order accelerator magnets. In the new ESRF-EBS storage ring, the sextupoles include additional windings allowing for dipole and skew quadrupole corrections. The accurate modelization of such magnets is not as trivial as it may appear, due to their non-linearities and to the crosstalk between their channels. Changing any corrector current induce non-linear errors in the other corrector channels and in the main sextupole strength, making difficult the trimming of the magnets. A model based on a non-linear excitation curve and quadratic contributions from corrector currents was developed. This model is very fast and was included in the accelerator control system to compute the corrector currents in real-time. It was tested against 3D magnetic simulations and magnetic measurements and compared to a simpler matrix-based model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB369

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paper received ※ 17 May 2021 paper accepted ※ 31 August 2021 issue date ※ 22 August 2021

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TUPAB372

Status of the Quadrupole Doublet Module Series Manfacturing

alignment, cryogenics, site, synchrotron

2388

T. Winkler, A. Bleile, L.H.J. Bozyk, V.I. Datskov, J. Ketter, P. Kowina, J.P. Meier, N. Pyka, C. Roux, P.J. Spiller, K. Sugita, A. Waldt, St. Wilfert
GSI, Darmstadt, Germany

The 83 Quadrupole Doublet Modules (QDM) for the heavy-ion-synchrotron SIS100 of the FAIR project at GSI are highly integrated cryogenic modules containing multiple magnets. Each of eleven different QDM types consists of two units, where one unit consists of one quadrupole magnet as well as corrector magnets depending on the modules position in the accelerator Ion-Optical Lattice. Additionally, the QDMs contain cryogenic collimators, beam diagnostics, as well as cryogenic UHV beam pipes. The modules contain parts from multiple suppliers increasing the logistics behinds the QDMs design further. We present the process of the module integration, give details on the current integration status and present an outlook on the timeline for the QDM integration planning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB372

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paper received ※ 18 May 2021 paper accepted ※ 02 June 2021 issue date ※ 21 August 2021

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TUPAB374

Development of a Quench Detection System for the FAIR Superconducting Devices

controls, superconducting-magnet, electron, interface

2394

V. Raginel, M. Dziewiecki, W. Freisleben, P.B. Szwangruber, L. Theiner
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR), which is presently under construction in Darmstadt (Germany), will incorporate a large variety of superconducting devices like magnets, currents leads and bus bars. These components depend on an active protection in case of a transition from superconducting to the resistive state, so-called quench. In this framework, a FAIR Quench Detection System (F-QDS) is being developed based on analog and digital electronics and will be implemented in several machines of the FAIR complex. This paper describes the development of the F-QDS. An overview of the F-QDS electronics is given followed by a description of the system integration to the infrastructure of various machines. Initial test results of the F-QDS prototype system are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB374

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paper received ※ 25 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

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TUPAB379

Superconducting Magnets for Super-FRS: Production and Testing Status

dipole, superconductivity, sextupole, superconducting-magnet

2405

H. Müller, A. Chiuchiolo, E.J. Cho, G. Golluccio, F. Greiner, P. Kosek, M. Michels, C. Roux, K. Sugita, V.V. Velonas, M. Winkler
GSI, Darmstadt, Germany
H. Allain, A. Madur
CEA-IRFU, Gif-sur-Yvette, France
A. Borceto, G. Drago, G. Valesi
ASG, Genova, Italy
M. Garcia Escudero, M. Lopez, J. Lucas
Elytt Energy, Madrid, Spain
G. Riddone, S. Russenschuck
CERN, Geneva, Switzerland

The Super FRS is a two-stage in flight separator to be built next to the site of GSI, Darmstadt, Germany as part of FAIR (Facility for Anti-proton and Ion Research). Its three branches allow to carry out a wide variety of experiments. Due to the large acceptance needed, the magnets of the Super-FRS require a large aperture and therefore only a superconducting solution is feasible. A superferric design was chosen in which the magnetic field is shaped by an iron yoke. For the dipole magnets only the superconducting coils are in a cryostat. These magnets are manufactured by Elytt Energy (Spain). The multiplets, assemblies of quadrupoles and higher order multipole magnets, are completely immersed in a liquid Helium bath. They are being built at ASG (Italy). The first of two first of series multiplets, a short assembly containing 2 magnets, was tested at a dedicated test facility at CERN (Switzerland). The 2nd FoS multiplet, containing 9 magnets, and the FoS dipole will be tested soon. Series production of the multiplets has started. In this paper we will present the status of production and testing of the different superconducting magnets for Super-FRS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB379

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paper received ※ 19 May 2021 paper accepted ※ 31 August 2021 issue date ※ 16 August 2021

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TUPAB380

Testing of the First of Series Quadrupole Doublet Module for the SIS100 Synchrotron

operation, synchrotron, superconducting-magnet, cryogenics

2409

P. Aguar Bartolome, M. Al Ghanem, M. Becker, A. Bleile, R. Bluemel, L.H.J. Bozyk, V.I. Datskov, W. Freisleben, A. Kario, P. Kowina, K.K. Kozlowski, F. Kurian, S. Lindner, J.P. Meier, T. Miertsch, S.S. Mohite, V.P. Plyusnin, I. Pongrac, C. Roux, C. Schroeder, P.J. Spiller, K. Sugita, A. Szwangruber, P.B. Szwangruber, F. Walter, H. Welker, St. Wilfert, T. Winkler, S. Zeller
GSI, Darmstadt, Germany

A new international facility for antiproton and ion research (FAIR) is currently under construction in Darmstadt, Germany. The high intensity primary beam required for different research experiments will be provided by the SIS100 heavy ion synchrotron. The synchrotron is composed of fast cycling superconducting magnets from which about 300 will be integrated in Quadrupole Doublet Modules (QDM). Each module consists of two units composed of a quadrupole and corrector magnets. The First of Series Quadrupole Doublet Module was delivered to the test facility at GSI in November 2019. The assembled doublet was subjected to a dedicated test program to verify the functionality of the module components at cryogenic temperature and operating conditions. The results obtained during the testing campaign will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB380

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paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 02 September 2021

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TUPAB383

Magnetic Field Performance of the First Serial Quadrupole Units for the SIS100 Synchrotron of FAIR

synchrotron, multipole, cryogenics, heavy-ion

2417

V.V. Borisov, O. Golubitsky, H.G. Khodzhibagiyan, B.Yu. Kondratiev, M.M. Shandov
JINR, Dubna, Moscow Region, Russia
E.S. Fischer, M.A. Kashunin, S.A. Kostromin, I. Nikolaichuk, T. Parfylo, A.V. Shemchuk, D.A. Zolotykh
JINR/VBLHEP, Dubna, Moscow region, Russia

The FAIR project is a new international accelerator complex, currently under construction in Darmstadt, Germany. The heavy-ion synchrotron SIS100 is the main accelerator of the whole complex. It will provide high-intensity primary beams with a magnetic rigidity of 100 Tm and a maximum repetition rate up to 4 Hz. The series production and testing of superconducting quadrupole units began in 2020 at JINR, Dubna. The first batch of units was delivered to Germany in September 2020. Each unit is subjected to a comprehensive testing program both at ambient temperature and under cryogenic conditions. We present the performance characteristics of the first quadrupole units (consisting of a lattice quadrupole magnet and correcting magnet mechanically and hydraulically coupled to a quadrupole). The main attention is paid to the field quality of the series of 6 quadrupoles measured by the same probe.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB383

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 01 September 2021

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TUPAB387

Superconducting Solenoid Field Measurement and Optimization

solenoid, emittance, multipole, gun

2425

S. Ma, A. Arnold, P. Murcek, A.A. Ryzhov, J. Schaber, J. Teichert, R. Xiang, P.Z. Zwartek
HZDR, Dresden, Germany
H.J. Qian
DESY Zeuthen, Zeuthen, Germany

The solenoid is a significant part of an electron injector to provide a proper focusing, and preserve the beam projected emittance. A superconducting solenoid is applied for the SRF photoinjector at HZDR. The solenoid itself can degrade electron beam quality due to magnetic field imperfections like multipole components. In order to determine the field aberrations in the solenoid, we measured the superconducting solenoid magnetic field in the cryomodule. A simple and effective method is used to analyze the multipole field components, which will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB387

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

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TUPAB388

Efficiency, Power Loss, and Power Factor Measurement of Quadrupole Magnet Power Supplies at the Spallation Neutron Source

power-supply, linac, controls, neutron

2428

S. Harave
ORNL, Oak Ridge, Tennessee, USA
B. Morris
SLAC, Menlo Park, California, USA

The linear accelerator (LINAC) quadrupole magnets are powered by 42 silicon-controlled rectifier (SCR) based power supplies at the Spallation Neutron Source (SNS) facility of Oak Ridge National Laboratory. These 35V, 525A power supplies are bulky, inefficient and require both air and water cooling. The reliability of the SNS facility is impacted due to water leaks internal to power supplies and current readback issues associated with their unique control system interface, resulting in multiple downtime events. Hence, an alternate solution is necessary for the continued reliable operation of the SNS. To mitigate the above-mentioned problems, this paper proposes the use of off-the-shelf Switch Mode Power Supplies (SMPS) rated for 20V, 500A with serial control interface. These SMPS are air-cooled, more efficient and more compact owing to their switching speeds of approximately 160 kHz. The performance enhancements of the SMPS in comparison with the existing SCR power supply are discussed in detail in this paper. The features of the SMPS, along with experimental results for both power supplies, like efficiency, power losses and stability, are presented. Ongoing work is also discussed.

Poster TUPAB388 [0.420 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB388

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paper received ※ 17 May 2021 paper accepted ※ 31 May 2021 issue date ※ 17 August 2021

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TUPAB391

Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18

simulation, vacuum, cryogenics, heavy-ion

2435

S. Aumüller, L.H.J. Bozyk, P.J. Spiller
GSI, Darmstadt, Germany
K. Blaum
MPI-K, Heidelberg, Germany

The FAIR complex at the GSI Helmholtzzentrum will generate heavy ion beams of ultimate intensities. To achieve this goal, medium charge states have to be used. However, the probability for charge exchange in collisions with residual gas particles of such ions is much higher than for higher charge states. In order to lower the residual gas density to extreme high vacuum conditions, 65% of the circumference of SIS18 are already coated with NEG, which provides high and distributed pumping speed. Nevertheless, nobel and nobel-like components, which have very high ionization cross sections, do not get pumped by this coating. A cryogenic environment at moderate temperatures, i.e. at 50-80K, provides high pumping speed for all heavy residual gas particles. The only typical residual gas species, that cannot be pumped at this temperature is hydrogen. With an additional NEG coating the pumping will be optimized for all residual gas particles. The installation of cryogenic surfaces in the existing room temperature synchrotron SIS18 at GSI has been investigated. A prototype quadrupole chamber with cryogenic surfaces, first measurements, and simulations of the adapted accelerator are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB391

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paper received ※ 19 May 2021 paper accepted ※ 31 August 2021 issue date ※ 25 August 2021

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TUPAB392

Conceptual Design of the Vacuum System for the Future Circular Collider FCC-ee Main Rings

vacuum, photon, collider, scattering

2438

R. Kersevan, C. Garion
CERN, Geneva, Switzerland

The Future Circular Collider study program comprises several machine concepts for the future of high-energy particle physics. Among them there is a twin-ring e⁻e⁺ collider capable to run at beam energies between 45.6 and 182.5 GeV, i.e. the energies corresponding to the resonances of the Z, W, H bosons and the top quark. The conceptual design of the two 100-km rings has advanced to what is believed to be a working solution, i.e. capability to deal with low-energy (45.6 GeV) high-current (1390 mA) version as well as the high-energy (182.5 GeV) low-current (5.4 mA) one, with intermediate energy and current steps for the other 2 resonances. The limit for all of the versions is given by the 50 MW/beam allotted to the synchrotron radiation (SR) losses. The paper will outline the main beam/machine parameters, the vacuum requirements, and the choices made concerning the vacuum chamber geometry, material, surface treatments, pumping system, and the related pressure profiles. The location of lumped SR photon absorbers for the generic arc cell has been determined. An outline of the studies needed and envisaged for the near future will also be given.

Poster TUPAB392 [3.036 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB392

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 25 August 2021

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TUPAB407

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

optics, proton, emittance, 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

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

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TUPAB415

Irradiation Methods and Infrastructure Concepts of New Beam Lines for NICA Applied Research

radiation, target, detector, diagnostics

2498

G.A. Filatov, A. Agapov, A.V. Butenko, K.N. Shipulin, A. Slivin, E. Syresin, A. Tuzikov, A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia
S. Antoine, W. Beeckman, X.G. Duveau, J. Guerra-Phillips, P.J. Jehanno
SIGMAPHI S.A., Vannes, France

Nowadays space exploration has faced the issue of radiation risk to microelectronics and biological objects. The new beamlines and irradiation stations of the Nuclotron-based Ion Collider fAcility (NICA) at JINR are currently under construction to study this issue. The beamline parameters, different methods for homogeneous irradiation of targets such as scanning, and beam profile shaping by octupole magnets are discussed. A short description of the building infrastructure, magnet elements, and detectors for these beamlines is also given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB415

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paper received ※ 11 May 2021 paper accepted ※ 02 June 2021 issue date ※ 13 August 2021

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WEPAB003

Overview of the Magnets Required for the Interaction Region of the Electron-Ion Collider (EIC)

electron, dipole, hadron, collider

2578

H. Witte, K. Amm, M. Anerella, J. Avronsart, A. Ben Yahia, J.P. Cozzolino, R.C. Gupta, H.M. Hocker, P. Kovach, G.J. Mahler, A. Marone, R.B. Palmer, B. Parker, S.R. Plate, C.E. Runyan, J. Schmalzle
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The planned electron-ion collider (EIC) at Brookhaven National Laboratory (BNL) is designed to deliver a peak luminosity of 1x10³⁴ cm^-2 s^-1. This paper presents an overview of the magnets required for the interaction region of the BNL EIC. To reduce risk and cost the IR is designed to employ conventional NbTi superconducting magnets. In the forward direction the magnets for the hadrons are required to pass a large neutron cone and particles with a transverse momentum of up to 1.3 GeV/c, which leads to large aperture requirements. In the rear direction the synchrotron radiation fan produced by the electron beam must not hit the magnet apertures, which determines their aperture. For the forward direction a mostly interleaved scheme is used for the optics, whereas for the rear side 2-in-1 magnets are employed. We present an overview of the EIC IR magnet design including the forward spectrometer magnet B0.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB003

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paper received ※ 18 May 2021 paper accepted ※ 01 July 2021 issue date ※ 29 August 2021

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WEPAB011

Update on the Low Emittance Tuning of the e⁺/e^- Future Circular Collider

alignment, emittance, sextupole, lattice

2601

T.K. Charles
The University of Liverpool, Liverpool, United Kingdom
B.J. Holzer, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project studies the design of a future 100 km e+/e circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2 s⁻¹. To achieve ultra-low vertical emittance a highly effective emittance tuning scheme is required. In this paper, we describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB011

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paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 02 September 2021

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WEPAB027

Optics Correction Strategy for Run 3 of the LHC

coupling, optics, dipole, MMI

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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WEPAB033

Lattice Design of the CEPC Collider Ring for a High Luminosity Scheme

luminosity, collider, lattice, dynamic-aperture

2679

Y. Wang, S. Bai, J. Gao, B. Wang, D. Wang, Y. Wei, J. Wu, C.H. Yu, J.Y. Zhai, Y. Zhang, Y.S. Zhu
IHEP, Beijing, People’s Republic of China
Y. Zhang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

A high luminosity scheme of the CEPC has been proposed aiming to increase the luminosity mainly at Higgs and Z modes. In this paper, the high luminosity scheme will be introduced briefly, including the beam parameters and RF staging. Then, the lattice design of the CEPC collider ring for the high luminosity scheme will be presented, including the bare lattice design and dynamic aperture optimization at Higgs energy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB033

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paper received ※ 20 May 2021 paper accepted ※ 05 July 2021 issue date ※ 27 August 2021

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WEPAB103

Systematic Beam Parameter Studies at the Injector Section of FLUTE

laser, emittance, cathode, electron

2837

T. Schmelzer, E. Bründermann, D. Hoffmann, I. Križnar, S. Marsching, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, N.J. Smale, P. Wesolowski, T. Windbichler
KIT, Karlsruhe, Germany

Funding: This work is supported by the DFG-funded Doctoral School "Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology (KSETA)"
FLUTE (Ferninfrarot Linac- und Test-Experiment) is a compact linac-based test facility for accelerator R&D and source of intense THz radiation for photon science. In preparation for the next experiments, the electron beam of the injector section of FLUTE has been characterized. In systematic studies the electron beam parameters, e.g., beam energy and emittance, are measured with several diagnostic systems. This knowledge allows the establishment of different operation settings and the optimization of electron beam parameters for future experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB103

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

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WEPAB128

Recent Experience with Magnet Sorting for APS-U Hybrid Undulators

undulator, photon, permanent-magnet, synchrotron

2910

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

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
The quality of permanent magnets plays a particularly important role in undulator performance. Many different types of magnet sorting to enhance undulator performance have been carried out at different facilities. Meanwhile, progress in improving magnet quality has been made by different vendors. At the Advanced Photon Source (APS) we have assembled, measured, and analyzed over 14 new undulators of the same mechanical design, some of them with sorted magnets and some unsorted. The performance differences appear to be insignificant in meeting the tight APS Upgrade (APS-U) undulator requirements.

Poster WEPAB128 [0.395 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB128

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paper received ※ 16 May 2021 paper accepted ※ 09 June 2021 issue date ※ 10 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, optics, dipole, 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]

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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, optics

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.

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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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WEPAB198

Beam Dynamics Design of a Synchrotron Injector with Laser-Accelerated Ions

laser, emittance, synchrotron, simulation

3085

M.Z. Tuo, X. Guan, W. Lu, P.F. Ma, Y. Wan, X.W. Wang, Q.Z. Xing, H.J. Yao, S.X. Zheng
TUB, Beijing, People’s Republic of China

We present, in this paper, the beam dynamics design of a linac injector with laser-accelerated carbon-ions for a medical synchrotron. In the design, the initial transverse divergence is reduced by two apertures. The beam is focused transversely through a quadrupole triplet lens downstream the apertures. The output energy spread of the extracted beam at the exit of the injector is compressed from ±6% to ±0.6% by a debuncher and a bend magnet system to meet the injection requirement for the synchrotron. By changing the width of imaging slit of the bend magnet system, the beam with energy of 4±0.024 MeV/u is extracted, and the particle number per shot and transverse emittances of the beam at the exit of the injector can be regulated through adjusting the slit height. The dynamics design can pave the way for the future concept research of the synchrotron injector.

Poster WEPAB198 [1.034 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB198

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

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WEPAB203

RFQ Beam Dynamics Optimization Using Machine Learning

rfq, simulation, focusing, network

3100

D. Koser, J.M. Conrad, L.H. Waites, D. Winklehner
MIT, Cambridge, Massachusetts, USA
A. Adelmann, M. Frey, S. Mayani
PSI, Villigen PSI, Switzerland

To efficiently inject a high-current H²⁺ beam into the 60 MeV driver cyclotron for the proposed IsoDAR project in neutrino physics, a novel direct-injection scheme is planned to be implemented using a compact radio-frequency quadrupole (RFQ) as a pre-buncher, being partially inserted into the cyclotron yoke. To optimize the RFQ beam dynamics design, machine learning approaches were investigated for creating a surrogate model of the RFQ. The required sample datasets are generated by standard beam dynamics simulation tools like PARMTEQM and RFQGen or more sophisticated PIC simulations. By reducing the computational complexity of multi-objective optimization problems, surrogate models allow to perform sensitivity studies and an optimization of the crucial RFQ beam output parameters like transmission and emittances. The time to solution might be reduced by up to several orders of magnitude. Here we discuss different methods of surrogate model creation (polynomial chaos expansion and neural networks) and identify present limitations of surrogate model accuracy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB203

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paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021

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WEPAB257

Matching of a Space-Charge Dominated Beam into the Undulator of the THz SASE FEL at PITZ

undulator, electron, experiment, FEL

3244

X. Li, Z. Aboulbanine, G.D. Adhikari, N. Aftab, Z.G. Amirkhanyan, P. Boonpornprasert, M.E. Castro Carballo, N. Chaisueb, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, O. Lishilin, A. Lueangaramwong, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany

The Photo Injector Test facility at DESY in Zeuthen (PITZ) is developing a THz SASE FEL as a prototype high repetition rate accelerator-based source for the THz-pumped, X-ray-probed experiments at the European XFEL. For the generation of THz pulses of mJ-level energy from SASE, an electron beam with a high charge (up to 4 nC) and high peak current (~200 A) will be injected into an LCLS-I undulator, which is currently being installed at the end of the photo-injector. The narrow vacuum chamber (11x5 mm) between the magnetic poles and the strong vertical focusing from the undulator, as well as the lack of beam diagnostics, have made it a challenge to match the space-charge dominated beam into the undulator without beam loss during the following transport. In this paper, boundary conditions of a matched electron beam will be discussed and the simulation and experimental study on our matching strategy will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB257

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paper received ※ 08 May 2021 paper accepted ※ 02 July 2021 issue date ※ 13 August 2021

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WEPAB303

Machine Learning Applied to Automated Tunes Control at the 1.5 GeV Synchrotron Light Source DELTA

storage-ring, simulation, controls, operation

3379

D. Schirmer
DELTA, Dortmund, Germany

Machine learning (ML) driven algorithms are finding more and more use cases in the domain of accelerator physics. Apart from correlation analysis in large data volumes, low and high level controls, like beam orbit correction, also non-linear feedback systems are possible application fields. This also includes monitoring the storage ring betatron tunes, as an important task for stable machine operation. For this purpose classical, shallow (non-deep), feed-forward neural networks (NNs) were investigated for automated adjusting the storage ring tunes. The NNs were trained with experimental machine data as well as with simulated data based on a lattice model of the DELTA storage ring. With both data sources comparable tune correction accuracies were achieved, both, in real machine operation and for the simulated storage ring model. In contrast to conventional PID methods, the trained NNs were able to approach the desired target tunes in fewer steps. The report summarizes the current status of this machine learning project and points out possible future improvements as well as other possible applications.

Poster WEPAB303 [1.575 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB303

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paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 25 August 2021

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WEPAB319

Open XAL Status Report 2021

framework, lattice, status, controls

3421

N. Milas, J.F. Esteban Müller, E. Laface, Y. Levinsen
ESS, Lund, Sweden
T.V. Gorlov, A.P. Shishlo, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

The Open XAL accelerator physics software platform is being developed through international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general-purpose accelerator applications). This paper discusses progress in beam dynamics simulation, new RF models, and updated application framework along with new generic accelerator physics applications. We present the current status of the project, a roadmap for continued development, and an overview of the project status at each participating facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB319

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paper received ※ 19 May 2021 paper accepted ※ 21 July 2021 issue date ※ 11 August 2021

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WEPAB355

Series Production of the SIS100 Cryocatchers

site, vacuum, cryogenics, heavy-ion

3529

L.H.J. Bozyk, S. Ahmed, P.J. Spiller
GSI, Darmstadt, Germany

The superconducting heavy ion synchrotron SIS100, which is the main accelerator of the FAIR-facility will be equipped with cryocatcher to suppress dynamic vacuum effects and to assure a reliable operation of high intensity heavy-ion beams. Subsequent to the successful validation of the prototype in 2011 as well as a First-of-Series cryocatcher, the series production of 60 cryocatcher modules meanwhile has been completed. It was released in 2018 after further design optimizations. Key findings from the series production and acceptance tests are presented as well. The First-of-Series cryocatcher has been integrated into the First-of-Series quadrupole module and has undergone several tests. These results are also illustrated in this report.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB355

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 16 August 2021

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WEPAB376

The Inner Triplet String Facility for HL-LHC: Design and Planning

cryogenics, operation, vacuum, MMI

3592

M.B. Bajko, S. Bertolasi, C. Bertone, S. Blanchard, D. Bozzini, O.S. Brüning, P. Cruikshank, D. De Luca, N. Dos Santos, F. Dragoni, N. Heredia Garcia, A. Herty, A. Kosmicki, S. Le Naour, W. Maan, A. Martínez Sellés, P. Martinez Urios, P. Orlandi, A. Perin, M. Pojer, F. Rodriguez-Mateos, G. Rolando, L. Rossi, H. Thiesen, E. Todesco, E. Vergara Fernandez, D. Wollmann, S. Yammine, J.J. Zawilinski, M. Zerlauth
CERN, Geneva, Switzerland

In the framework of the HL-LHC project, full-scale integration and operational tests of the superconducting magnet chain, from the inner triplet quadrupoles up to the first separation/recombination dipole, are planned in conditions as similar as possible to the final set-up in the LHC tunnel. The IT String includes all of the required systems for operation at nominal conditions, such as vacuum, cryogenics, warm and cold powering equipment, and protection systems. The IT String is intended to be both an assembly, and an integration test stand, and a full rehearsal of the systems working in unison. It will, closely reproducing the mechanical, electrical, and thermo-hydraulic interfaces of the final installation, as well as allowing a full rehearsal of the systems working in unison. This paper describes the conceptual design, the test stand’s reference configuration, and the main goals. It also summarizes the status of the main activities, including the detailed design of the test infrastructure, procurement of main equipment, the baseline installation schedule, and major milestones. The first version of the experimental program and the associated planning are also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB376

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paper received ※ 19 May 2021 paper accepted ※ 22 July 2021 issue date ※ 22 August 2021

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WEPAB383

An Evolutionary Algorithm Approach to Multi-Pass ERL Optics Design

linac, optics, 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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WEPAB398

A C-Band RF Mode Launcher with Quadrupole Field Components Cancellation for High Brightness Applications

network, GUI, brightness, linac

3638

G. Pedrocchi
SBAI, Roma, Italy
D. Alesini, F. Cardelli, A. Gallo, A. Giribono, B. Spataro
INFN/LNF, Frascati, Italy
G. Castorina
AVO-ADAM, Meyrin, Switzerland
L. Ficcadenti
INFN-Roma, Roma, Italy
M. Migliorati, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy

The R&D of high gradient radiofrequency devices is aimed to develop innovative and compact accelerating stuctures based on new manufactoring techniques and materials in order to produce devices operating with the highest accelerating gradient. Recent studies have shown a large increase in the maximum sustained RF surface electric fields in copper structure operating at cryogenic temperature. These novel approaches allow significant performance improvements of RF photoinjectors. Indeed the operation at high surface fields results in considerable increase of electron brilliance. This requires high field quality in the RF photoinjector and specifically in its poweer coupler. In this work we present a novel power coupler for the RF photoinjector. The coupler is a compact C-band TM01 mode launcher with a fourfold symmetry which minimized both the dipole and the quadrupole RF field components.

Poster WEPAB398 [1.799 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB398

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paper received ※ 13 May 2021 paper accepted ※ 06 July 2021 issue date ※ 23 August 2021

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WEPAB399

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

optics, lattice, experiment, injection

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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THXA01

Beyond RMS: Understanding the Evolution of Beam Distributions in High Intensity Linacs

simulation, rfq, MEBT, space-charge

3681

K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau, A.P. Shishlo, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: This work has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Understanding the evolution of beams with space charge is crucial to design and operation of high intensity linacs. While the community holds a broad understanding of the mechanisms leading to emittance growth and halo formation, there is outstanding discrepancy between measurements and beam evolution models that precludes prediction of halo losses. This may be due in part to insufficient information of the initial beam distribution. This talk will describe work at the SNS Beam Test Facility to directly measure the 6D beam distribution. Full-and-direct 6D measurement has revealed hidden but physically significant dependence between the longitudinal distribution and transverse coordinates. This nonlinear correlation is driven by space charge and reproduced by self-consistent simulation of the RFQ. Omission of this interplane correlation, common when bunches are reconstructed from lower-dimensional measurements, degrades downstream predictions. This talk will also describe the novel diagnostics supporting this work. This includes ongoing improvements to efficiency of the 6D phase space measurement as well as recent achievement of six orders of dynamic range in 2D phase space.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA01

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paper received ※ 20 May 2021 paper accepted ※ 23 July 2021 issue date ※ 17 August 2021

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THXB05

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

optics, 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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THPAB001

Reaching the Sub Per Mil Level Coupling Corrections in the LHC

coupling, simulation, dipole, operation

3752

E.J. Høydalsvik, T.H.B. Persson
CERN, Geneva, Switzerland

The High Luminosity LHC (HL-LHC) is requiring sub per mil coupling correction, as defined by the closest tune approach. In this article, the current coupling correction strategy is analyzed in order to understand if it can robustly correct to these very low levels. The impact of realistic errors on the coupling correction is investigated with MAD-X simulations, including the influence of local coupling on the global coupling correction. Through simulations and measurements in the LHC, the effect of BPM noise on the coupling correction is analyzed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB001

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paper received ※ 11 May 2021 paper accepted ※ 28 July 2021 issue date ※ 23 August 2021

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THPAB002

Lattice Design for BEPCII Upgrade

cavity, lattice, dynamic-aperture, electron

3756

H. Geng, W.B. Liu, J. Qiu, J. Xing, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high-energy physics study. Along with the deepening of the research, more important physics is expected in higher energy regions (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. In this paper, the lattice design for the upgrade of BEPCII is studied. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of the BEPCII beam with a reasonable margin.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB002

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paper received ※ 14 May 2021 paper accepted ※ 17 June 2021 issue date ※ 14 August 2021

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THPAB012

The Magnetic Compensation Scheme of the FCC-ee Detectors

solenoid, detector, emittance, electron

3773

M. Koratzinos, K. Oide
CERN, Meyrin, Switzerland

A crucial part of the design of an FCC-ee detector is the minimisation of the disruption of the beam due to the presence of a large and powerful detector magnet. Indeed, the emittance blow-up of the few meters around the interaction point (IP) at lower energies is comparable to the emittance introduced by the rest of the 100 km ring. Vertical emittance is the single most important factor in achieving high performance (luminosity, in this case) in a modern e⁺ e⁻ storage ring such as the FCC-ee. The design adopted is the simplest possible arrangement that can nevertheless deliver high performance: two additional coils per IP side. The performance achieved is such that vertical emittance blow-up will not be a limiting performance factor even in the case of a ring with four experiments, and even in the most demanding energy regime, that of the Z running (about 45 GeV beam energy).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB012

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paper received ※ 10 May 2021 paper accepted ※ 28 July 2021 issue date ※ 30 August 2021

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THPAB013

Magnetic Measurements at Warm of the First FCC-ee Final Focus Quadrupole Prototype

multipole, induction, simulation, factory

3777

M. Koratzinos
MIT, Cambridge, Massachusetts, USA
G. Kirby, M. Liebsch, C. Petrone
CERN, Geneva, Switzerland

The first FCC-ee final focus quadrupole prototype has been designed, manufactured, assembled and tested at warm. The prototype is a single aperture quadrupole magnet of the CCT type. One edge of the magnet was designed with local multipole cancellation, whereas the other was left with the conventional design. An optimized rotating induction-coil sensor was used. A technique was developed to take into account field distortions due to the environment of the test and distinguish them from magnet effects, demonstrating an excellent field quality for the prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB013

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paper received ※ 11 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021

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THPAB031

Dump Line Layout and Beam Dilution Pattern Optimization of the Future Circular Collider

kicker, target, extraction, hardware

3815

B. Facskó, D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
A. Lechner, E. Renner
CERN, Geneva, Switzerland

To avoid any damage to the beam dump target in the Future Circular Collider, the beam will be swept over its surface using oscillating kickers in the x/y planes with a 90-degree phase difference, and an amplitude changing in time, creating a spiral pattern. The ideal pattern must have an increasing spiral pitch towards smaller radii to produce an even energy deposition density. We recommend the realization of the optimal pattern using two beating frequencies. This method enables a flat energy deposition density while only using simple independent damped oscillators. In this poster, we also present the study of the beamline optics and hardware that can realize the needed pattern. Two different possible hardware layouts were examined and optimized as well.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB031

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021

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THPAB047

Status of Magnetic Measurement Benches for Insertion Device Characterization at MAX IV Laboratory

undulator, insertion, insertion-device, MMI

3848

M. Ebbeni, M. Gehlot, M. Holz, H. Tarawneh
MAX IV Laboratory, Lund University, Lund, Sweden

Insertion Devices (IDs) are the sole source of radiation used in all beamlines in MAX IV Laboratory with 14 IDs in operation of which 6 were built in-house. This paper shows the current capabilities and performance of the of the ID magnetic measurement systems, and the ongoing development work.

Poster THPAB047 [1.185 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB047

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paper received ※ 11 May 2021 paper accepted ※ 27 July 2021 issue date ※ 28 August 2021

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THPAB066

Ground Diffusion Measurement and Its Effect on APS-U Orbit Stability

ground-motion, electron, alignment, simulation

3907

V. Sajaev
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Spatial and temporal ground diffusion can be approximately described by the ATL law*,**. Ground diffusion can have an important effect on the long-term stability of the accelerator alignment. To estimate the possible consequences of the ground diffusion on the APS Upgrade performance, the ground diffusion constant of the existing APS tunnel was measured using historical data of the orbit correction effort and then used to estimate the ground diffusion effect on the orbit stability of the APS Upgrade. In this paper, we will describe the diffusion constant measurement and present the estimations of the expected APS-U alignment and orbit stability.
* B.A. Baklakov et. al., Technical Physics, v.38(10), pp.894-898(1993)
** V. Shiltsev, Physical Review Letters, 104(23), p.238501 (2010).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB066

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paper received ※ 12 May 2021 paper accepted ※ 13 July 2021 issue date ※ 24 August 2021

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THPAB071

Physics Goals of DWA Experiments at FACET-II

experiment, wakefield, acceleration, focusing

3922

J.B. Rosenzweig, H.S. Ancelin, G. Andonian, A. Fukasawa, C.E. Hansel, G.E. Lawler, W.J. Lynn, N. Majernik, J.I. Mann, P. Manwani, Y. Sakai, O. Williams, M. Yadav
UCLA, Los Angeles, California, USA
S.V. Baryshev
Michigan State University, East Lansing, Michigan, USA
S. Baturin
Northern Illinois University, DeKalb, Illinois, USA
M.J. Hogan, B.D. O’Shea, D.W. Storey, V. Yakimenko
SLAC, Menlo Park, California, USA

Funding: This work supported by DOE HEP Grant DE-SC0009914,
The dielectric wakefield acceleration (DWA) program at FACET produced a multitude of new physics results that range from GeV/m acceleration to the discovery of high field-induced conductivity in THz waves, and beyond, to a demonstration of positron-driven wakes. Here we review the rich program now developing in the DWA experiments at FACET-II. With increases in beam quality, a key feature of this program is extended interaction lengths, near 0.5 m, permitting GeV-class acceleration. Detailed physics studies in this context include beam breakup and its control through the exploitation of DWA structure symmetry. The next step in understanding DWA limits requires the exploration of new materials with low loss tangent, large bandgap, and improved thermal characteristics. Advanced structures with photonic features for mode confinement and exclusion of the field from the dielectric, as well as quasi-optical handling of coherent Cerenkov signals is discussed. Use of DWA for laser-based injection and advanced temporal diagnostics is examined.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB071

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paper received ※ 25 May 2021 paper accepted ※ 28 July 2021 issue date ※ 22 August 2021

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THPAB077

Magnetic Shims Studies for APS-U Hybrid Permanent Magnet Undulators

undulator, multipole, simulation, GUI

3941

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

Funding: Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357
For the newly designed and fabricated APS Upgrade (APS-U) hybrid permanent magnet undulators (HPMUs), the development of magnetic shims has been critical to successfully tuning the undulators to meet the tight APS-U physics requirements. Different types of side and surface shims have been developed and applied for this purpose. The side shims are primarily used for trajectory tuning, and the surface shims are for phase and multipole tuning as well as trajectory tuning. Current design, applications, and measurement of the shims for the newly designed and fabricated APS28 (28 mm period) undulators are presented in this paper.

Poster THPAB077 [0.531 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB077

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paper received ※ 20 May 2021 paper accepted ※ 18 June 2021 issue date ※ 27 August 2021

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THPAB089

Lattice Design for a Future Plan of UVSOR Synchrotron

emittance, dynamic-aperture, optics, lattice

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]

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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, optics

3980

J. Chen, Y. Jiao, X. Liu, S. Wang
IHEP, Beijing, People’s Republic of China
Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China

There are various magnetic errors in the actual accelerator, which will significantly affect the beam quality and machine performance. The diffraction-limited storage ring (DLSR) of Southern Advanced Photon Source (SAPS) will use a large number of ultra-high gradient quadrupoles and sextupoles, which, in turn, leads to the tight tolerance of beam parameters to magnetic errors. Based on a preliminary designed storage ring lattice of the SAPS, the influence of various magnetic errors on lattice parameters has been evaluated.

Poster THPAB104 [0.588 MB]

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

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

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THPAB124

Application of the FFA Concept to a Muon Collider Complex

collider, lattice, optics, focusing

4006

S. Machida, J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
M.E. Topp-Mugglestone
JAI, Oxford, United Kingdom

Muon collider complex is one of the places where the concept of fixed field alternating gradient (FFA) optics can be applied with great benefits. Vertical excursion FFA (vFFA) provides the isochronous condition for the ultra-relativistic muon beams after pre-acceleration. Together with the fixed transverse tune, it will be an ideal accelerator of short-lived muon beams with no time variation of magnetic fields and RF frequency. Novel collider ring optics is a design based on skew quadrupole after extracting essential functions from vFFA. That enables control of the momentum compaction factor. Neutrinos from the continuing decay of muons are spread out with orbit wiggling in the vertical direction as well as horizontal. The paper discusses the underline principle and describes some design examples.

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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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THPAB170

RF Deflector Design for Rapid Proton Therapy

proton, cavity, simulation, polarization

4086

E.J.C. Snively, G.B. Bowden, V.A. Dolgashev, Z. Li, E.A. Nanni, D.T. Palmer, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: This work is supported by US Department of Energy Contract No. DE-AC02-76SF00515.
Pencil beam scanning of charged particle beams is a key technology enabling high dose rate cancer therapy. The potential benefits of high-speed dose delivery include not only a reduction in total treatment time and improvements to motion management during treatment but also the possibility of enhanced healthy tissue sparing through the FLASH effect, a promising new treatment modality. We present here the design of an RF deflector operating at 2.856 GHz for the rapid steering of 150 MeV proton beams. The design utilizes a TE11-like mode supported by two posts protruding into a pillbox geometry to form an RF dipole. This configuration provides a significant enhancement to the efficiency of the structure, characterized by a transverse shunt impedance of 68 MOhm/m, as compared to a conventional TM11 deflector. We discuss simulations of the structure performance for several operating configurations including the addition of a permanent magnet quadrupole to amplify the RF-driven deflection. In addition to simulation studies, we will present preliminary results from a 3-cell prototype fabricated using four copper slabs to accommodate the non-axially symmetric cell geometry.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB170

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

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THPAB177

Simulation Model Improvements at the Cooler Synchrotron COSY Using the LOCO Algorithm

simulation, storage-ring, dipole, polarization

4111

V. Poncza, A. Lehrach
FZJ, Jülich, Germany
A. Lehrach, V. Poncza
RWTH, Aachen, Germany

Funding: ERC Advanced Grant (srEDM #694340) of the European Union
The JEDI (Jülich Electric Dipole moment Investigations) collaboration is searching for Electric Dipol Moments (EDMs) of charged particles in storage rings. In a stepwise approach, a first direct deuteron EDM measurement was performed at the Cooler Synchrotron COSY and design studies for a dedicated proton EDM storage ring are underway. In an experiment with a polarized beam in a storage ring, an EDM leads to a vertical polarization buildup. However, the vertical polarization component is also induced by systematic effects such as magnet misalignments. To investigate systematic effects individually and to support data analysis, a realistic simulation model of the storage ring is needed. In this paper, the development of such a model based on the Bmad software library is presented. Furthermore, various systematic effects and their impact on the spin motion in COSY are investigated and quantified by means of beam and spin tracking simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB177

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paper received ※ 19 May 2021 paper accepted ※ 27 July 2021 issue date ※ 12 August 2021

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THPAB180

Simulation of 4D Emittance Measurement at the Spallation Neutron Source

emittance, simulation, space-charge, optics

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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THPAB205

On-Line Retuning of ISAC Linac Beam with Quadrupole Scan Tomography

ISAC, MEBT, rfq, diagnostics

4187

O. Shelbaya, R.A. Baartman, P.M. Jung, O.K. Kester, S. Kiy, T. Planche, Y.-N. Rao, S.D. Rädel
TRIUMF, Vancouver, Canada

The method of tomographic reconstruction has been in use at TRIUMF and elsewhere for several years, allowing for the beam diagnostic extraction of elements of the beam matrix on-line. One of the more recent applications of the technique at ISAC consists of using the measured density distribution as the input parameters for a real-time tune re-computation. This technique is advantageous since it does not require installation of dedicated emittance meters, but can instead be carried out with existing position monitors. Instead of requiring an operator to manually re-tune quadrupoles in a matching section, which can be time consuming, the technique allows for a fast and reproducible means to precisely control the beam and can be proceduralized for use by operators tuning the machine.

Poster THPAB205 [0.468 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB205

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paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 10 August 2021

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THPAB224

The Correction of Time-Dependent Tune Shift by Harmonic Injection

focusing, injection, simulation, neutron

4234

X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China
J. Chen, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

In the Rapid Cycling Synchrotron(RCS) of China Spallation Neutron Source(CSNS), transverse painting injection is employed to suppress the space-charge effects. The beta-beating caused by edge focusing of the injection bump magnets leads to tune shift. A new method based on the harmonic injection is firstly introduced to correct the time-dependent tune shift caused by the edge focusing effect of the chicane bump magnets in RCS. The simulation study was done on the application of the new method to the CSNS/RCS, and the results show the validity and effectiveness of the method.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB224

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paper received ※ 19 May 2021 paper accepted ※ 16 July 2021 issue date ※ 10 August 2021

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THPAB230

Design of Split Permanent Magnet Quadrupoles for Small Aperture Implementation

permanent-magnet, electron, focusing, simulation

4247

I.I. Gadjev, G. Andonian, T.J. Campese, M. Ruelas
RadiaBeam, Santa Monica, California, USA
C.C. Hall
RadiaSoft LLC, Boulder, Colorado, USA

Permanent magnet quadrupoles are ideal for strong focusing in compact footprints. Recent research in the use of permanent magnet based quadrupole magnets has enabled very high-gradient uses approaching 800T/m in final focus systems. However, in order to achieve high quality field profiles with strong fields, small diameter bore magnets must be used necessitating in vacuum operation, or very small beampipes. For small beampipe geometry, we have developed a hybrid-permanent magnet quadrupole, with steel and permanent magnet wedges, that is able to maintain high quality fields but also readily machinable in a separable design. The split design allows for accurate and reproducible reconfiguration on a beam pipe. In this paper, we will discuss the design, engineering, fabrication and first measurements of the split permanent magnet quadrupole.

Poster THPAB230 [1.605 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB230

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paper received ※ 15 May 2021 paper accepted ※ 08 July 2021 issue date ※ 30 August 2021

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THPAB232

Study of Nonlinear Properties of ESR via Tune Scans

closed-orbit, optics, storage-ring, controls

4250

G. Franchetti
GSI, Darmstadt, Germany

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

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

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

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THPAB245

A Simulation Study of Beam Pipe Eddy Current Effects on Beam Optics

simulation, operation, vacuum, power-supply

4288

T. Asami, T. Koseki
The University of Tokyo, Graduate School of Science, Tokyo, Japan
S. Igarashi, T. Koseki, Y. Kurimoto, Y. Sato
KEK, Ibaraki, Japan

In synchrotrons, fast changes of magnetic field induce eddy currents at the wall of beam pipes. The eddy currents cause a phase delay between excitation currents of the magnets and the magnetic field. The undesired magnetic field affected by eddy currents might be a serious obstacle in controlling beam optics precisely. In fact, in the operation of a high-intensity proton synchrotron J-PARC MR, the largest beam loss is observed at the beginning of acceleration when the magnetic field starts to vary in time. Therefore, it is important to estimate and understand the effects of eddy currents on beam optics. In this study, we have calculated the effect of eddy currents on magnetic field for some magnets in J-PARC MR, using electromagnetic simulation software. In this paper, we would like to report the details and results of the simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB245

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paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 17 August 2021

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THPAB286

Quadrupole Focusing Lenses for Heavy Ion Linac

DTL, focusing, flattop, operation

4359

V. Skachkov, A.V. Kozlov, G. Kropachev, T. Kulevoy, D.A. Liakin, O.S. Sergeeva, V.S. Skachkov, Yu. Stasevich
ITEP, Moscow, Russia

Simulation results of pulsed current electromagnet quadrupoles with integral of the magnetic field gradient up to 7 T are presented. Magnets for the DTL and MEBT focusing channels are designing for the heavy-ion linac in Institute for Theoretical and Experimental Physics (ITEP - NRC "Kurchatov Institute"). Appropriate conditions which promise getting the magnetic lens parameters required at restrictions on the overall length <130 mm as well as on the beam aperture >45 mm are defined. It is shown that the channel acceptance to beam emittance ratio desired not less than 3 can be provided by conventional low-carbon steel up to a magnetic aperture of 50 mm in diameter while beyond this size permendur is out of competition. Some aspects of the pulsed power supply system are considered and main parameters of the pulse current generator (PCG) are given.

Poster THPAB286 [0.701 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB286

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paper received ※ 14 May 2021 paper accepted ※ 30 June 2021 issue date ※ 02 September 2021

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THPAB295

Application of CMM Technology in Accelerator Magnet Detection

software, detector, hardware, radiation

4381

S. Li, F.S. Chen, C.D. Deng, W. Kang, Y.Q. Liu, X. Wu, Y.W. Wu
IHEP, Beijing, People’s Republic of China

Accelerator magnet is one of the most difficult equipment in accelerator hardware system. With the improvement of physical requirements, more and more high technical requirements are put forward for magnets. This paper mainly introduces the new application of three coordinate measurement technology in the detection of accelerator magnet, and introduces the working process of CMM in the detection of accelerator magnet polar profile.

Poster THPAB295 [0.677 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB295

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paper received ※ 14 May 2021 paper accepted ※ 02 September 2021 issue date ※ 29 August 2021

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THPAB309

New Working Tune Feedback System for TLS

feedback, insertion, insertion-device, radiation

4394

S.J. Huang, Y.K. Lin, Y.C. Lin
NSRRC, Hsinchu, Taiwan

TLS storage ring has two sets of working tuning feedback systems: one is used to correct the working tune deviation caused by insertion device U90; another system uses a local trim coil to correct the working tune deviation caused by all insertion devices. This article describes a new working tune feedback system in TLS that can correct the working tune effectively back to the required conditions for operation; the two existing feedback systems do not cause problems. We can both avoid increasing the local radiation dose and decreasing the injection efficiency.

Poster THPAB309 [0.831 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB309

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paper received ※ 15 May 2021 paper accepted ※ 02 July 2021 issue date ※ 23 August 2021

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THPAB328

Tapered Modular Quadrupole Magnet to Reduce Higher-Order Optical Aberrations

focusing, simulation, operation, optics

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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