sextupole
MOZN1
Overview of permanent magnet implementations for advanced light sources
42
The utilization of permanent magnets in the design of accelerator magnets has witnessed a surge in prominence, particularly within the realm of advanced light sources. Following pioneering initiatives at SIRIUS and ESRF-EBS, current projects are increasingly embracing permanent magnet technology. Notably, in the case of SLS2.0, over 30% of the magnets in the new storage ring are powered with permanent magnets. Permanent magnets offer manifold advantages, including compactness, much simpler requirements in terms of services (such as power supplies, cables, and cooling systems), and reduced operational costs. Nonetheless, they also present significant challenges that demand careful consideration. In this study, the author provides an overview of permanent magnet implementations across various projects and delves into a detailed analysis of the Swiss Light Source upgrade.
Paper: MOZN1
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOZN1
About: Received: 02 Jun 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPB002
An IGBT pulser for the nonlinear in-vacuum kicker at Taiwan Photon Source
72
A test unit pulser for the proposed NIK (nonlinear in-vacuum kicker) project at TPS (Taiwan Photon Source) was fabricated in order to provide uniform kick strength applying onto the injected bunch train. This newly built flattop pulser gives much improved drive current pulse shape in comparison with previously used half-sine pulser. This flattop pulser will result in high injection efficiency and provide adjustable capability in terms of bunch train filling pattern.
Paper: MOPB002
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB002
About: Received: 20 Apr 2025 — Revised: 14 Jun 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
MOPB033
A novel design of a magnetic chicane with positive R56
130
It has been attracting attention that the energy chirp, which is formed by the space-charge effect of the electron beam and the beam wake field when the beam passes through the accelerator tube, can be used to generate short-pulse XFELs. Since the energy chirp produced by this phenomenon is such that the energy of electrons in the rear of the bunch is lower than at the front, compression requires a magnetic chicane with a positive R56, which shortens the path of the lower energy electrons. On the other hand, a normal simple electromagnetic chicane would have a negative R56, not applicable to this bunch compression. In this presentation, we report on the idea of a compact R56-positive magnetic chicane that can be inserted in a straight section and the results of its design study.
Paper: MOPB033
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB033
About: Received: 27 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPB053
Preliminary beta beating correction at the Canadian Light Source
169
The Canadian Light Source does not currently correct beta beating driven by its insertions devices. However, it has been known for some time that insertion device correlated vertical beam size changes can cause large reduction in flux at the VESPERS beamline. In this work we discuss our preliminary explorations to control the vertical beam size and correct beta beating.
Paper: MOPB053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB053
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPB065
Application of fast algorithms to calculate dynamic and momentum aperture to the design of ALBA II
197
In synchrotron light sources, the non-linear magnetic fields and Touschek scattering limit the stability of electron motion, determining the dynamic aperture (DA) and the momentum acceptance (MA). Optimizing both the DA and the MA is crucial to maximize injection efficiency and the beam's lifetime, but it is numerically expensive. We implement recently developed algorithms that speed-up their calculation in CPUs: Flood Fill and Fast Touschek Tracking (FTT). Applying these to the analysis of the ALBA II lattice and comparing them to the existing methods, we obtain rigorous and faster results using Flood Fill, and ones with a slight loss of accuracy for FTT.
Paper: MOPB065
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB065
About: Received: 31 Mar 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPB072
Magnet crosstalk in highly-compact light-source storage ring
208
Electron storage rings based on multi-bend achromat (MBA) lattice can achieve very low natural emittances. Several fourth generation light sources have been built and operating, the natural emittances of which are a few 100 pm or even lower than 100 pm, providing high brightness photon beams to users. Since the lattice of MBA storage ring tends to be highly compact, the field of a magnet may be affected by the neighboring magnets. This effect turned out to be significant in the new Swiss Light Source storage ring with 7-BA lattice during its design study: the integral fields of magnets are altered by a few percent due to the magnet cross talk at locations, which is an order of magnitude larger than the field precision typically required. We present how we managed to reproduce the design magnetic fields and optics including the cross talk effects
Paper: MOPB072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB072
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
MOPB100
An alternative lattice for the ZIPS storage ring
239
Since synchrotron radiation sources have many advanced characteristics such as high radiation power, high brightness, broad spectral range, transverse coherence, and excellent time structure, they have become powerful tools for exploring microscopic material structures. With the growing demand for industrial researches, several dedicated industrial light sources are under operation or construction around the world. Zhejiang Industrial Photon Source (ZIPS) is designed to provide a scientific platform for industrial applications within the X-ray region in China. As a preliminary design, the ZIPS storage ring adopts a modified Triple-Bend Achromat (TBA) lattice with an energy of 2.6 GeV and a low emittance of 3.88 nm · rad. Details of the lattice design are presented in this paper.
Paper: MOPB100
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB100
About: Received: 10 Apr 2025 — Revised: 30 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
MOPB101
Bayesian optimization for the local bump injection in the HLS-II storage ring
242
Currently, a conventional local bump injection system with four pulsed dipole kicker magnets is adopted in the Hefei Light Source II (HLS-II) storage ring to achieve topoff operation. Due to the multipole magnets located between the kickers in the injection section, the local bump injection presents technical challenges in forming a perfect closed bump, which causes oscillation to the stored beam. In order to reduce the injection disturbance on the stored beam, the Bayesian Optimization (BO) method is employed to determine the kick angles of the four bump kickers.
Paper: MOPB101
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPB101
About: Received: 09 Apr 2025 — Revised: 31 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPM003
Lattice correction and polarization estimation for the future circular collider e+e-
267
Precise determination of the center-of-mass energy at the Future Circular Collider (FCC-ee) operating at the Z and W resonance energies relies on resonant spin depolarization techniques, which require a sufficient level of transverse beam polarization in the presence of machine imperfections. In this study, the FCC-ee lattice is modeled and simulated under a range of realistic imperfections, complemented by refined orbit correction and tune-matching procedures. The equilibrium polarization is computed within these realistic machine models to investigate the causes of polarization loss and explore potential improvements through lattice optimization. Additionally, spin tune shifts, which contribute to systematic errors, are estimated to support the precision requirements of the energy calibration experiment.
Paper: MOPM003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM003
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM010
Emittance tuning of the FCC-ee high energy booster ring
286
The Future Circular Collider (FCC), in its leptonic configuration has been chosen by CERN as main proposition for the next high-energy collider. This project aims to achieve luminosities one to two orders of magnitude higher than ever. Feasibility studies have led to the definition of tolerances on magnet imperfections and correction strategies. This is crucial for ensuring the performance of one of the main elements of the acceleration chain, the High Energy Booster (HEB) ring. The efficiency and overall performance of these strategies greatly influence new magnet specifications and tolerances, affecting main optic functions. Horizontal and vertical orbit corrections use horizontal and vertical kickers, respectively. Skew quadrupoles address vertical dispersion and transverse coupling. Normal quadrupoles correct the horizontal and vertical phase advances. This study simulates the distribution of these four corrector types to minimize the equilibrium emittance at the extraction energy of 45.6 GeV. The calculated strengths of these correctors and the associated misalignments are presented. The study also discusses the limitations and drawbacks of the proposed correction strategy.
Paper: MOPM010
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM010
About: Received: 29 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM019
Correction of Long-Range Beam-Beam Driven Normal Sextupolar Resonance Driving Terms
322
Beam-based studies at the LHC injection energy showed that compensation of the strongly driven sextupolar resonance, Qx+2Qy, improved both the dynamic aperture and lifetime of the beam, even when far from the working point and on the far side of the 3Qy resonance. Thus, a reduction of other strong normal sextupolar resonance sources was of interest. In 2024, the first measurements of resonance driving terms with long-range beam-beam (LRBB) interactions were performed. These showed that LRBB was driving the same Qx+2Qy resonance strongly when colliding, in agreement with model predictions. A correction was found for the strongest normal sextupole resonances using the existing sextupole corrector magnets in the LHC, obeying the constraints on the chromatic coupling and the maximum magnet powering. Beam-based tests to validate the response of this correction with non-colliding beams have been performed along with the testing of the LRBB resonance correction during LHC commissioning.
Paper: MOPM019
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM019
About: Received: 23 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM027
Impact of ground motion on FCC-ee performance
354
The Future Circular Collider for electron-positron collisions (FCC-ee) is a proposed next-generation particle accelerator aimed at achieving high luminosity and precision for fundamental particle physics experiments. Its performance is sensitive to environmental factors such as ground motion, which can induce vibrations and misalignments in critical accelerator components. This paper presents a detailed study on the impact of ground motion on FCC-ee performance, with a focus on beam stability, alignment tolerances, and the complex interplay between ground motion and operational parameters. Using advanced simulations and analytical modeling, we evaluate the FCC-ee's sensitivity to various ground motion scenarios, ranging from localized, uncorrelated disturbances to correlated plane waves, and analyze their effects on the beam optics, orbit distortions, and overall beam dynamics. The findings provide valuable insights into the design and operational strategies required to mitigate ground motion effects, guiding future research and engineering efforts to ensure the successful realization of the FCC-ee project.
Paper: MOPM027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM027
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM028
Interplay between sextupole settings and single particle instabilities during the FCC-ee commissioning
358
The Future Circular Collider of electrons and positrons (FCC-ee) is designed to achieve high luminosity at center-of-mass energies ranging from the Z boson peak to the top quark threshold. During the commissioning phase, specialized optics are essential to accommodate the dynamic needs of machine tuning and beam stabilization. This paper investigates the role of sextupoles in the various FCC-ee commissioning optics, focusing on their influence on nonlinear beam dynamics. Using advanced simulation tools, we analyze how sextupole configurations impact key performance indicators, including the dynamic aperture, emittance evolution and lifetime. Strategies for optimizing sextupole strengths are explored. The findings provide critical insights for the design and optimization of the commissioning optics, ensuring efficient and reliable ramp-up to nominal operation. These results are instrumental in refining the FCC-ee commissioning strategy, supporting its broader objectives for particle physics research.
Paper: MOPM028
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM028
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
MOPM029
Progress on the 10 TeV center-of-mass energy muon collider
362
A 10 TeV center-of-mass muon collider could serve as a next-generation high-energy lepton collider with substantial physics potential while offering a more compact footprint than other proposed machines. However, this collider presents unique challenges, largely due to the short lifetime of muons and their decay products. Specifically, the collider ring requires specialized designs to protect the magnets and detectors while ensuring negligible neutrino radiation at Earth's surface. The high required luminosity also imposes stringent constraints, including very small beta functions at the interaction points that lead to strong chromatic effects. To meet these challenges, high-field combined-function magnets are used to create a compact layout with minimal straight sections. Flexible momentum compaction arc cells are used to maintain short bunch lengths and local chromatic correction sections to address the chromatic aberrations from the interaction regions. This work presents recent advancements in the 10 TeV muon collider ring, including interaction region improvements to reduce beam-induced background and a study that investigates the impact of $\beta^*$ on the dynamic and momentum acceptance.
Paper: MOPM029
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM029
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPM039
Updated monochromatization Interaction Region optics design for FCC-ee GHC lattice
402
Determining Yukawa couplings of the Higgs boson is one of the most fundamental and outstanding measurements since its discovery. The FCC-ee, owing to its exceptionally high-integrated luminosity, offers the unique opportunity to measure the electron Yukawa coupling through s-channel Higgs production at 125 GeV centre-of-mass (CM) energy, provided that the CM energy spread can be reduced from 50 MeV to a level comparable to the Higgs bosons’ natural width of 4.1 MeV. To improve the energy resolution and reach the desired collision energy spread, the concept of a monochromatization mode has been proposed as a new operation mode at the FCC-ee, relying on the Interaction Region (IR) optics design with a nonzero dispersion function of opposite signs at the interaction point (IP). A first optics design and preliminary beam dynamics simulations have been carried out for V22 of the FCC-ee GHC lattice type. In response to the continuously evolving FCC-ee GHC optics, this paper presents the first updated monochromatization IR optics design based on V23 of the FCC-ee GHC optics.
Paper: MOPM039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM039
About: Received: 28 May 2025 — Revised: 05 Jun 2025 — Accepted: 06 Jun 2025 — Issue date: 10 Jul 2025
MOPM109
Beam-based alignment techniques for the FCC-ee
571
The Future electron-positron Circular Collider (FCC-ee) is a proposed lepton collider for high-energy particle physics succeeding the Large Hadron Collider (LHC). Its ambitious design goals demand excellent orbit and optics control and, therefore, set strict limits on alignment tolerances. One approach to relax the mechanical alignment tolerances is Beam-Based Alignment (BBA), where the offset between magnet and position measurement is determined and can later be used to steer the beam towards the magnetic centre using corrector magnets. One of the key challenges of the FCC-ee is developing an accurate and fast BBA strategy for quadrupoles and sextupoles. A parallel BBA technique is evaluated and compared in simulations for the baseline and an alternative lattice for FCC-ee using Xsuite and is presented in this paper.
Paper: MOPM109
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPM109
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS015
Exploring the null space of the chromaticity response matrix at the Diamond Light Source
615
Many different techniques have been investigated at Diamond for optimising sextupole strengths*. One method not previously studied is to exploit the null space of the chromaticity response matrix. By performing a singular value decomposition (SVD) of the chromaticity response matrix, combinations of sextupole strengths are identified which alter the nonlinear lattice whilst keeping the chromaticity unchanged. Applying these sextupole strength changes opens an avenue to improve the beam lifetime and the injection efficiency at fixed chromaticity, thereby preserving the instability thresholds from collective effects. The results of applying this technique are presented both for beam tracking simulations for the Diamond-II lattice, including machine errors, and for machine-based measurements on the present Diamond synchrotron.
Paper: MOPS015
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS015
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPS016
Multi-objective optimisation of the Diamond-II storage ring optics
619
The design performance of the 3.5 GeV Diamond-II low-emittance electron storage ring has been studied as a function of the linear and nonlinear lattice tuning parameters. A Multi-Objective Genetic Algorithm (MOGA) has been implemented to optimise both the beam lifetime and the injection efficiency for off-axis injection. The simulations have been run on 5 machine error seeds, including misalignment and field strength errors, to obtain a solution which is robust against machine imperfections. The results of the optimisation are presented alongside a comparison of the baseline performance.
Paper: MOPS016
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS016
About: Received: 28 May 2025 — Revised: 30 May 2025 — Accepted: 01 Jun 2025 — Issue date: 10 Jul 2025
MOPS039
Direct MOGA optimization of touschek lifetime and dynamic aperture using fast touschek tracking
694
A large momentum acceptance (MA) in 4th generation storage ring light sources is paramount to obtaining a long Touschek lifetime. However, the calculation of MA typically requires computationally expensive tracking simulations thereby complicating, or even disabling, the direct optimization of Touschek lifetime using numerical optimization algorithms. Our recent development of Fast Touschek Tracking allows obtaining the MA two orders of magnitude faster than standard MA tracking, thereby enabling direct optimization of Touschek lifetime. We present an example of a Multi-Objective Genetic Algorithm (MOGA) optimization of both on-energy dynamic aperture and direct Touschek lifetime using Fast Touschek Tracking for a 4th generation storage ring.
Paper: MOPS039
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS039
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS040
Start to end commissioning simulations for SOLEIL II storage ring
698
This paper presents comprehensive start-to-end commissioning simulations for the SOLEIL II storage ring upgrade, demonstrating the feasibility of achieving an ultra-low emittance of 84 pm-rad at 2.75 GeV. We detail a multi-step correction strategy addressing challenges posed by the dense magnet arrangement and limited number of BPMs and correctors. Our simulations encompass first turn trajectory correction, beam-based alignment (BBA), and Linear Optics from Closed Orbit (LOCO) techniques. Results demonstrate the robustness of the correction scheme in the presence of realistic errors, showing successful recovery of design emittance, suitable dynamic aperture, and expected beam lifetime. This work provides insights into an efficient commissioning strategy for SOLEIL II, supporting rapid commissioning and full performance restoration for user operations.
Paper: MOPS040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS040
About: Received: 27 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
MOPS083
Tune domain behavior of single magnet lattices
785
Single-sextupole and single-octupole lattices ``exhibit .. all the typical properties of more complicated mappings and dynamical issues'', including horizontal resonances of all orders $N$ with island tunes $Q_I$. In general both island tune response spectra and tune modulation drive spectra have multiple lines. Stable motion in transverse phase space is compromised when a pair of drive and response lines align. This vulnerability is illustrated by realistic examples from the Relativistic Heavy Ion Collider.
Paper: MOPS083
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS083
About: Received: 11 May 2025 — Revised: 31 May 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
MOPS089
The Korea-4GSR storage ring lattice design
789
We present the lattice design features and performance evaluation of the Korea-4GSR storage ring. This greenfield ring has a 4 GeV beam energy, an 800 m circumference, and 28 cells. A natural emittance of 62 pm is achieved through the implementation of four longitudinal-gradient bends and six reverse bends within the hybrid multi-bend achromat unit cell. The ring includes two high-beta straights, designed to be nearly transparent to the normal straights. Sextupole and octupole magnet strengths have been optimized to suppress major detuning parameters, enabling the ring to achieve a large dynamic aperture and momentum aperture. Commissioning simulations were performed to investigate the optics correction strategy for each commissioning stage and to estimate the performance of the ring under error conditions.
Paper: MOPS089
DOI: reference for this paper: 10.18429/JACoW-IPAC25-MOPS089
About: Received: 23 May 2025 — Revised: 01 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
TUBD3
Optimization of the Korea-4GSR storage ring for increasing the off-momentum dynamic aperture by analyzing resonance driving terms
887
The Korea-4GSR is a next-generation diffraction-limited light source designed to provide beam brightness up to 100 times greater than existing facilities. Chromatic aberrations from strong focusing fields in quadrupoles are corrected using sextupoles and octupoles. However, these sextupoles and octupoles introduce nonlinear effects, causing electrons to follow nonlinear trajectories, ultimately reducing beam lifetime. Consequently, these nonlinear elements negatively impact both the dynamic aperture and local momentum aperture. The limitations on local momentum aperture are primarily due to transverse nonlinear dynamics. Recent studies have shown that minimizing one-turn resonance driving terms, reducing their fluctuations, or controlling amplitude-dependent tune shifts (ADTS) can enhance both dynamic aperture and local momentum aperture in various storage ring configurations, including DBA, MBA, and hybrid-MBA lattices. Therefore, we aim to optimize resonance driving terms using a Multi-Objective Genetic Algorithm (MOGA) to expand on- and off-momentum dynamic apertures and improve beam lifetime by increasing local momentum aperture for the Korea-4GSR.
Paper: TUBD3
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUBD3
About: Received: 02 Jun 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPB013
Towards axion searches with polarized hadron beams at GSI/FAIR
972
Axions, originally introduced to solve the strong CP problem, are leading dark matter candidates appearing in various Standard Model extensions. At low masses, axion-like particle (ALP) dark matter behaves as a classical field, potentially detectable when its frequency resonates with a beam's spin-precession frequency. The JEDI collaboration's proof-of-principle experiment at COSY set upper limits on oscillating EDMs caused by ALPs, though no signals were observed. This presentation discusses COSY results and recent efforts to explore the feasibility of conducting axion search experiments using existing accelerators at GSI/FAIR with polarized hadron beams.
Paper: TUPB013
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPB013
About: Received: 27 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
TUPM014
Deflecting cavity-based multifunctional longitudinal manipulator for CSR-mitigated bunch compression
1192
A deflecting cavity is an interesting tool providing a coupling between transverse and longitudinal planes. Several methods employing deflecting cavities have been proposed to shape current profiles or adjust longitudinal chirp. Even, a method using deflecting cavities was recently proposed for imparting arbitrary correlation on the longitudinal phase space. In this work, we introduce an integrated deflecting cavity-based beam manipulator capable of simultaneously controlling three longitudinal properties: chirp, linearity, and current profile. This relatively compact system can provide a linearized longitudinal chirp for bunch compression without requiring linac phase control and harmonic linearizers. Also, it generates a current profile that flattens the CSR wake, thereby minimizing emittance growth caused by CSR. The presentation includes the working principle of the system and simulation results.
Paper: TUPM014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM014
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
TUPM072
Two in-vacuum undulators developed for the Sirius
1326
The Shanghai Synchrotron Radiation Facility (SSRF) project team developed two in-vacuum undulators (IVUs) with a period length of 18.5 mm and a gap of 4 mm for the SIRIUS. This paper introduces the design and magnetic field measurements. The results indicate that with a gap range of 4-20 mm, the phase error is less than 3°, the quadrupole field is less than 37 Gs, the sextupole field is less than 83 Gs/cm, and the octupole field is less than 84 Gs/cm².
Paper: TUPM072
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPM072
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 14 Jun 2025 — Issue date: 10 Jul 2025
TUPS115
Optimization of the driver energy deposition in plasma wakefield acceleration simulations by varying transverse offset of sextupole magnets
1611
Plasma Wakefield Acceleration (PWFA) is a method of accelerating charged particles using a plasma. It has the potential to produce exceptionally large accelerating gradients on the order of 10’s of GeV/m. The FACET-II test facility accelerates pairs of 10 GeV electron bunches to study the PWFA process—a drive bunch to produce a wake in the plasma in a lithium-ion oven, and a witness bunch to be accelerated by PWFA. By using arrangements of sextupole magnets, it is possible to alter the chromaticity and other energy-dependent properties of the beams prior to their entry into the plasma. The purpose of this study was to determine how the transverse offsets of the sextupole magnets could be optimized to increase the amount of energy deposited into the plasma by the drive bunch as this energy deposition is critical to maximising the efficiency of PWFA. To achieve this, a simulation of the FACET-II beamline was performed with sextupole offsets as adjustable parameters in a Bayesian Optimization procedure. The results demonstrate the value of using beam simulations as guides to improve the PWFA process, thereby reducing the need to perform costly experiments at the FACET-II facility.
Paper: TUPS115
DOI: reference for this paper: 10.18429/JACoW-IPAC25-TUPS115
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPB026
Magnetic design of the cSTART magnets
1788
The KIT project cSTART (compact STorage ring for Accelerator Research and Technology) aims to store ultra-short electron bunches in a very-large-acceptance compact storage ring. The magnetic lattice of the storage ring is laid out for a variety of beam optics, including ultra-low positive and negative alpha as well as isochronous optics. These put high demands on the magnet quality and alignment. The spatial constraints for the storage ring impose further challenges on the magnet design. In this contribution, we give an overview of both the challenges and solutions for the cSTART storage ring magnet design.
Paper: WEPB026
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB026
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPB027
Compact quadrupole-sextupole magnet units for the FLUTE-cSTART injection line
1792
One of the major goals of the cSTART project (compact STorage ring for Accelerator Research and Technology) at KIT is injecting and storing ultra-short bunches from the FLUTE linac into a very large-acceptance compact storage ring. To cope with the spatial constraints of the injection line connecting FLUTE with the storage ring three meters above, compact quadrupole-sextupole magnet units were designed, fabricated, and characterised. In this contribution, we describe the magnetic design of these units and the underlying considerations, particularly with respect to cross-talk effects and their mitigation by design. We present the results of rotating coil and Hall probe measurements validating the magnetic design.
Paper: WEPB027
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB027
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB042
Third order resonance correction using new Trim-S system in J-PARC MR
1826
In the Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), to address the issue of resonance correction for third-order resonances in both on- and off-momentum particles, an upgrade project utilizing 24 Trim-S units has been proposed based on numerical simulations. As a first step in verifying its effectiveness, four additional Trim-S (new Trim-S) power supplies, configured with a System-on-Chip (SoC) Field Programmable Gate Array (FPGA) controller, have been installed. The performance of the new system was experimentally verified by correcting the resonance using these 4 new Trim-S units. Beam loss was successfully reduced compared to that with the original Trim-S system, demonstrating the effectiveness of the new system.
Paper: WEPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB042
About: Received: 14 Apr 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB045
Performance Analysis and Stability Enhancement Plan for the Sextupole Magnet Power Supply in Storage Ring
1836
Since its official operation in 2016, the Taiwan Photon Source (TPS) has been dedicated to providing a stable and high-quality synchrotron radiation light source. The TPS storage ring is divided into 24 sections, each equipped with 7 sextupole power supply units, totaling 168 units. These power supplies are responsible for delivering precise and stable current to drive the sextupole magnets. This paper focuses on evaluating the long-term operational stability of the sextupole power supply system since its commissioning and proposes a targeted upgrade strategy to address potential reliability issues. To enhance overall system stability and yield, and to effectively reduce the frequency of beam trips caused by power supply faults, an upgrade plan involving the adoption of ultra-high-precision power supplies has been proposed. In addition, the removed high-precision power supplies will be repurposed as spares to improve system redundancy and fault response capability. The upgrade project is scheduled for full implementation by 2028. A pilot installation has already been completed in Cell 22, and successful electron beam storage was achieved at the end of 2024. Preliminary assessments suggest that, upon completion, the upgrade will reduce the number of beam trip events by approximately 2 to 3 times per year and decrease the total annual downtime by around 4 to 6 hours, thereby significantly improving the operational reliability of the TPS storage ring and the quality of service provided to users.
Paper: WEPB045
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB045
About: Received: 22 Apr 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPB048
Magnetic measurement of a decommissioned insertion device at the Canadian Light Source
1843
The Canadian Light Source has decommissioned three insertion devices in recent years, replacing each with upgraded devices. The decommissioned devices are planar undulators that have seen approximately 15 years of operation in a 2.9 GeV storage ring, two being out-of-vacuum devices with 45 mm and 185 mm periods and one being an in-vacuum 20 mm device. In this paper we present magnetic measurements of the decommissioned 185 mm device (U185) with comparisons against the original measurements from before it was put into service.
Paper: WEPB048
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPB048
About: Received: 24 May 2025 — Revised: 30 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPM001
High Luminosity LHC optics: Machine development results
1948
As the High Luminosity LHC (HL-LHC) era approaches, precise control of the accelerator becomes increasingly critical. Machine studies are essential to address the forthcoming challenges and develop correction strategies based on experimental measurements. Although the upgraded inner triplets are not yet available, key features of the HL-LHC optics can still be investigated. This includes exploring the high Achromatic Telescopic Squeeze (ATS) factors in the neighboring arcs of the high-luminosity interaction regions, particularly under flat optics configurations. A beta blow-up is also implemented in the long straight section containing most of the beam instrumentation to improve their sensitivity at top energy. This paper presents experimental measurements, evaluates arc phase errors, and discusses the implementation of local corrections. Sextupole bumps in the arcs were employed to mitigate these errors, demonstrating their effectiveness in optimizing machine performance.
Paper: WEPM001
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM001
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM006
Optics optimization and commissioning simulations for Elettra 2.0
1960
Optimization of dynamic aperture is a challenging aspect of low emittance storage ring lattice design. A large dynamic aperture is favourable for efficient injection and long beam lifetime. Several methods like simple scanning of sextupoles and octupoles strength and genetic optimization with different configurations have been successfully combined to enlarge the dynamic aperture of Elettra 2.0 and ensure high efficiency injection. Using the optimized machine we then study its commissioning via simulations including and discussing the various stages from injection to the first turn, to accumulation.
Paper: WEPM006
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM006
About: Received: 27 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM008
3Qy resonance correction at LHC injection
1964
Compensation of the 3Qy resonance at injection energy in the LHC is of significant interest, given its potential to degrade the lifetime of high-intensity beams. In the absence of dedicated corrector circuits for the 3Qy compensation of each beam at low energy, an alternative approach is needed. Using skew-sextupoles in the four common experimental insertions it has been possible to develop a scheme to independently control the 3Qy resonance of the two LHC beams. Beam-based measurements and corrections of the 3Qy resonance at injection were performed, with beneficial impacts on lifetime and emittance growth observed.
Paper: WEPM008
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM008
About: Received: 27 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM023
BESSY III orbit correction scheme layout and performance
2004
Currently in its Conceptual Design Phase (CDR), the 4th generation light source BESSY III aims to become a world-leading soft X-ray source, enabling numerous applications in metrology, life sciences, energy and catalysis materials, and many more. Its performance relies on ultra-low transverse emittances, achieved through the use of strong focusing magnetic elements that are sensitive to magnetic and alignment errors. If left uncorrected, these errors give rise to a distortion of the closed orbit, beta beating, linear coupling, and a stronger impact of resonances thus impairing the storage ring performance. In this work, we address how to devise an initial BESSY III orbit correction scheme. Two criteria were considered to find the optimal locations of Beam Position Monitor (BPM) and dipolar Corrector Magnet (CM). Different orbit correction scheme candidates are presented and their advantages and disadvantages are discussed. All calculations were performed in parallel with the Matlab toolkit Simulated Commissioning (SC) and its Python counterpart (pySC).
Paper: WEPM023
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM023
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM032
Online optimization of beam lifetime by Bayesian Optimization in TPS
2032
The beam lifetime in synchrotron light sources is critically influenced by nonlinear beam dynamics, particularly in low-emittance storage rings where the Touschek effect dominates. At the Taiwan Photon Source (TPS), a third-generation 3 GeV storage ring, optimization of harmonic sextupole magnet strengths has been conducted using Bayesian Optimization (BO) techniques to minimize beam loss monitor (BLM) readings and thereby enhance beam lifetime. This study demonstrates an integrated approach to nonlinear optics tuning using machine learning, with constraints on chromaticity correction. The experimental implementation involves tuning harmonic sextupole families. Results indicate significant improvements in lifetime while maintaining machine stability, demonstrating the potential of data-driven control in modern accelerator operations, establishing this technique as a powerful tool for synchrotron light source operation. This paper details the implementation, experimental validation, and performance analysis of BO in optimizing beam lifetime at TPS.
Paper: WEPM032
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM032
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 03 Jun 2025 — Issue date: 10 Jul 2025
WEPM035
Resonance Driving Terms characterization at VEPP-2000 collider
2044
The VEPP-2000 collider is a compact machine, which uses the round-beam concept to achieve high luminosity. Its compact size (24 m in circumference) limits the free space between the magnetic elements. Only 4 BPMs are installed in the ring with large phase advance between them (~2 pi). The key to improve its luminosity is to reduce the power of resonances. The implementing of the RDT measurement technique with our limitations is discussed. The presented experimental data gives basic information on the location of the considered magnetic perturbation causing the RDT.
Paper: WEPM035
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM035
About: Received: 28 May 2025 — Revised: 03 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM040
Improving the beam extraction efficiency from SPS to the North Area at CERN using octupole phase space folding technique
2058
The High Intensity ECN3 (HI-ECN3) project aims to increase the number of protons per pulse delivered to a new experimental facility in CERN’s North Area up to $\sim 4 \cdot 10^{19}$ per year. Such an upgrade requires the reduction of the beam loss at SPS electrostatic septum (ZS) by at least a factor of four, since the activation of this device is the main factor constraining transition to the higher beam intensity. In this work we demonstrate one of the possible solutions to this problem that relies on octupole assisted folding of the beam in phase space. Implementation of this technique allowed to significantly reduce the losses at the ZS whilst transferring the beam through the LSS2 line, which connects the SPS and the transfer lines in the North Area, without deteriorating the transmission.
Paper: WEPM040
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM040
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM052
Observation of transverse resonance island buckets at the ESRF EBS
2089
The presence of third order horizontal resonance island buckets at the ESRF EBS has been observed in simulations and in the machine. The islands appear at a few mm distance from the core with a specific horizontal tune and octupole setting. When the electrons are kicked with an injection kicker, a fraction of the beam can be captured in the island. The procedures to send the beam into the island and to measure the capture rate and the lifetime of the beam in the island are described. The dependency of the presence of stable islands with different horizontal and vertical tunes and different octupole settings are shown.
Paper: WEPM052
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM052
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPM053
On the optimization of the non-linear lattice of BESSY III
2093
Helmholtz-Zentrum Berlin plans to construct a fourth- generation greenfield synchrotron light source in the early 2030s to replace BESSY II, a 1.7 GeV machine that has been running since 1998. The optimization of the linear lattice already considers non-linear aspects, such as minimizing the necessary sextupole strength and, for the minimal case of two families of sextupoles, phase cancellation to reduce the resonant driving terms. In preparation for the final optimization of 8 sextupole families and the single octupole, different approaches are compared: multi-objective genetic optimization, for a lattice with given error sets and orbit correction on the one hand, and the minimization of the resonant driving terms and the detuning terms on the other hand. Here, analytic formulas are used, so after a single evaluation of the Twiss parameters, the driving terms can be determined for different combinations of sextupole and octupole values. The results will determine the strategy for optimizing the lattice’s non-linear behavior, i.e., dynamic aperture and momentum acceptance, taking the efficiency of the optimization into account.
Paper: WEPM053
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM053
About: Received: 26 May 2025 — Revised: 05 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
WEPM063
Symmetric double-double bend lattice for a potential EUV diffraction limited upgrade of the HLS
2113
NSRL recently proposed a future plan to further upgrade the HLS to an EUV diffraction-limited storage ring, named HLS-III. In this paper, a symmetric double-double bend lattice with long and mid-straight sections is studied as a highly promising design for the HLS-III storage ring. The design achieves an ultra-low natural emittance of 2.82 nm·rad at 800 MeV, while maintaining the current eight straight sections but with significantly reduced beta functions in these straights. By minimizing the fluctuation of resonance driving terms, the nonlinear dynamics optimization yields a large horizontal dynamic aperture of about 40 mm. Additionally, error and intra-beam scattering effects are evaluated.
Paper: WEPM063
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM063
About: Received: 08 Apr 2025 — Revised: 31 May 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPM105
Progress on the 5BA lattice studies for ALBA-II
2222
ALBA-II is progressing in the definition of an upgrade lattice that meets the requirements of the beamlines and perform well in terms of dynamics aperture and lifetime. The last changes were focused on further decreasing both the emittance (200 pm*rad) and the beta functions at the straight sections (around 2 m) for the improvement of the beamlines performances. The efforts to guarantee a good performance of such a lattice have been focused on the improvement of a horizontal dynamic aperture larger than 6 mm (needed for off-axis injection) and of a lifetime around 10 hours. Octupole magnets next to each sextupole have been introduced to correct the large tune shift with amplitude that is limiting the dynamic aperture. Simulations of the lattice commissioning and robustness with magnet, alignment and instrumentation errors are being carried out. The efficiency of the off-axis injection process including both lattice and pulsed elements errors is also under evaluation.
Paper: WEPM105
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM105
About: Received: 27 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
WEPM111
Experimental validation of parallel quadrupole beam-based alignment at KARA
2229
The Karlsruhe Research Accelerator (KARA), a synchrotron light source and test facility, at the Karlsruhe Institute of Technology (KIT), offers excellent conditions for testing different Beam-Based Alignment (BBA) approaches. Classical BBA approaches estimate the offset between the magnet and the closest BPM for one magnet at a time, and the required time for the BBA scales linearly with the number of magnets. Therefore, this approach is unsuitable for large storage rings like the Future electron-positron Circular Collider (FCC-ee). The time required is reduced using parallel BBA, where the magnet offset for several magnets is determined simultaneously. In this contribution, we compare new methods of parallel and individual BBA for quadrupoles at KARA. The measurement results are complemented with simulations using Xsuite and optics measurements.
Paper: WEPM111
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPM111
About: Received: 09 May 2025 — Revised: 04 Jun 2025 — Accepted: 04 Jun 2025 — Issue date: 10 Jul 2025
WEPS003
Study of operation above half-integer random resonance in the J-PARC RCS
2244
In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the beam power ramp-up aiming to surpass the design of 1 MW enhances the space charge effect. It pushes the beam toward the structure resonance. To mitigate the beam loss, the operating point is required to be apart from the structure resonance as the beam power ramp-up. However, large beam loss was observed when the operating point was set near the half-integer resonance. Thus, the maximum beam power of the RCS is currently limited so that the beam does not overlap the structure resonance or half-integer random resonance. To address this issue and achieve the beam power ramp-up, we experimentally studied the half-integer resonance compensation using trim quadrupole magnets. In addition, detailed numerical simulations were performed to develop a better understanding. The experimental and numerical results of the operation above half-integer random resonance are presented.
Paper: WEPS003
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS003
About: Received: 28 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
WEPS021
Simulation study on attosecond bunch generation using reversed chicane at Argonne Wakefield Accelerator (AWA)
2286
Capability for generating an attosecond bunch can provide interesting opportunities to wakefield accelerator research. We have been studying requirements and challenges in beam dynamics to produce an attosecond bunch using an existing beamline at Argonne Wakefield Accelerator (AWA) facility. One unavoidable limitation of this study is that conventional C-typed chicane is not available. Thus, a modified version of a chicane-like compressor, called a reversed chicane, is designed and running at the AWA facility. AWA’s injector and beamline were simulated using ASTRA and ELEGANT respectively. The study provided guidance toward the attosecond bunch generation. We present the simulation results and propose the modified design and operation conditions to generate the attosecond bunch at AWA facility.
Paper: WEPS021
DOI: reference for this paper: 10.18429/JACoW-IPAC25-WEPS021
About: Received: 28 May 2025 — Revised: 31 May 2025 — Accepted: 31 May 2025 — Issue date: 10 Jul 2025
THPB014
A vibrating wire system for multipole magnets alignment in TPS
2529
An auto-scanning vibrating wire system for magnets centering alignment was developed at NSRRC. It is prepared for the replacement of magnets on the girder of TPS storage ring in case of malfunction and also as a pre-study topic of the TPS upgrade. With this system, both quadrupole and sextupole magnets were tested in the laboratory. This paper presents the system configuration and testing results.
Paper: THPB014
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB014
About: Received: 29 May 2025 — Revised: 03 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPB042
Design and first prototype results of PETRA-IV permanent magnet dipole-quadrupoles
2594
Permanent magnet-based dipoles will be an essential part of the future PETRA-IV light source at DESY. The bending magnets are combined-function DQ-magnets, which provide moderate focusing with a B/G ratio of about 0.03m. Each DQ consists of several C-shaped modules, one of the three types additionally having a stepwise longitudinal gradient. Several prototype modules have recently been manufactured. The paper describes the magnet design, compares manufacturing peculiarities, and discusses first magnetic measurement results.
Paper: THPB042
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPB042
About: Received: 26 May 2025 — Revised: 02 Jun 2025 — Accepted: 02 Jun 2025 — Issue date: 10 Jul 2025
THPM017
Uncertainty-Quantified Machine Model Construction Using Physics-Informed Gaussian Processes and Bayesian Optimization
2718
To construct a closed orbit model for an accelerator ring with intrinsic uncertainty quantification from orbit measurements, a physics-informed Gaussian Process model is proposed based on a stochastic ensemble of MAD-X lattices. Key advantages compared to LOCO (Linear Optics from Closed Orbits) include (1.) uncertainty-enabled orbit prediction in between BPMs (beam position monitors), (2.) fitting of a parameter distribution (dipole-like field errors) which inherently models uncertainty, (3.) incorporation of measurement uncertainty from BPM noise, and (4.) an active learning approach which can be more sample efficient than measuring an orbit response matrix. A case study is presented for the GSI heavy ion synchrotron SIS18 with various simulated applications, in particular constructing an effective machine model with minimal orbit uncertainty around the ring, and orbit correction to achieve minimal deviation at a specific location such as, e.g., the septum to control beam loss during slow extraction. This physics-inspired Gaussian Process regression approach shows potential to be applied to optics correction and further applications beyond closed orbit correction.
Paper: THPM017
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM017
About: Received: 28 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025
THPM102
High efficiency multi-objective Bayesian algorithm for APS-U nonlinear dynamics tuning
2905
The Advanced Photon Source (APS) facility has just completed an upgrade to become one of the world’s brightest storage-ring light sources. Machine learning (ML) methods have seen extensive use during commissioning. One important application was multi-objective tuning of dynamic aperture and lifetime, a complex high-dimensionality task intractable with classic optimization methods. In this work we will discuss novel Bayesian optimization (BO) algorithmic and implementation improvements that enabled this use case. Namely, pre-training and uncertainty-aware simulation priors, dynamic parameter space and acquisition function refinement, and an adaptive wall-time convergence criteria. We will also show results of optimization runs from 10 to 24 dimensions, benchmarking scaling and efficiency as compared to standard MOGA and MGGPO. Given the promising performance, work is proceeding on tighter BO integration into the control room.
Paper: THPM102
DOI: reference for this paper: 10.18429/JACoW-IPAC25-THPM102
About: Received: 29 May 2025 — Revised: 04 Jun 2025 — Accepted: 05 Jun 2025 — Issue date: 10 Jul 2025