HB2023 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
MOA4I1	Design of a Fixed-Field Accelerating Ring for High Power Applications	injection, extraction, synchrotron, lattice	38
	S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	A fixed field accelerating ring (FFA) has some advantage to achieve high beam power over conventional ring accelerators. It would be also a sustainable option as future proton drivers. We will discuss the design of an FFA taking a future upgrade plan of ISIS (ISIS-II) as an example.
	Slides MOA4I1 [14.313 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA4I1
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 15 October 2023 — Issued ※ 21 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC3I3	Laser Stripping of H⁻ Beam	laser, experiment, injection, proton	141
	T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz ORNL, Oak Ridge, Tennessee, USA N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA P.K. Saha JAEA/J-PARC, Tokai-mura, Japan
	Basic principles of laser assisted charge exchange injection for H⁻ ion andH⁰ beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.
	Slides TUC3I3 [1.790 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3
About •	Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA1I2	Analytical and Numerical Studies on Kicked Beams in the Context of Half-Integer Studies	space-charge, coupling, emittance, damping	188
	G. Franchetti GSI, Darmstadt, Germany F. Asvesta, H. Bartosik, T. Prebibaj CERN, Meyrin, Switzerland
	In the context of the half-integer studies an investigation of the dynamics of the kicked beam has revealed surprising properties. The coupling of space charge with chromatic- ity in addition to usual damping/non-damping dynamics, exhibits new properties typical of a linear coupling. This proceeding covers the status of these studies carried out with analytical and numerical approaches and the prelimi- nary results of experimental investigations in the CERN PS Booster.
	Slides WEA1I2 [24.966 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1I2
About •	Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 24 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2I1	Compensation of Third-order Resonances in the High Intensity Regime	sextupole, space-charge, operation, experiment	215
	C.E. Gonzalez-Ortiz MSU, East Lansing, Michigan, USA R. Ainsworth Fermilab, Batavia, Illinois, USA P.N. Ostroumov FRIB, East Lansing, Michigan, USA
	As the Fermilab Accelerator Complex enters the high-intensity era, the Recycler Ring (RR) needs to mitigate the detrimental effect of third-order resonance crossing. Third-order resonance lines can be compensated to first order by cancelling out the global Resonance Driving Terms (RDTs) using the response matrix method. This compensation scheme has been proven to work at low intensities, i.e., in the single-particle regime. In order to evaluate the effectiveness of this compensation scheme at higher intensities, this study looks at dynamic and static tune scans, with and without resonance compensation, and different space charge tune shifts. Special care was taken in order to disentangle effects from space charge tune shift, structure resonances and space charge driven resonances.
	Slides WEA2I1 [6.714 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I1
About •	Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 09 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2I2	Space Charge Induced Resonances and Suppression in J-PARC MR	optics, space-charge, simulation, operation	222
	T. Yasui KEK, Tokai, Ibaraki, Japan
	In the main ring synchrotron (MR) of Japan Proton Accelerator Research Complex (J-PARC), space charge induced resonances are the cause of beam losses. Although we have scanned the tunes to minimize beam losses, it has been difficult to completely avoid high order structure resonances because the MR has only three super-periodicities. In the present settings for the neutrino operation, we identified that the space charge induced resonance 8ny=171 is the main source of beam losses, except for random resonances. We found that this resonance can be suppressed by beam optics modification while maintaining the tune. In this talk, we present the theoretical, simulation, and experimental results showing the advantages of the new beam optics and the reasons for them.
	Slides WEA2I2 [6.189 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I2
About •	Received ※ 07 November 2023 — Accepted ※ 18 November 2023 — Issued ※ 29 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2C1	Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS	space-charge, acceleration, ECR, simulation	228
	S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang IHEP, Beijing, People’s Republic of China
	The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.
	Slides WEA2C1 [4.710 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2C2	Measurement of Transverse Statistical Dependence for Non-Gaussian Beam Distributions via Resonances in the CERN PSB	space-charge, experiment, factory, luminosity	231
	E.R. Lamb, F. Asvesta, H. Bartosik, G. Sterbini CERN, Meyrin, Switzerland E.R. Lamb EPFL, Lausanne, Switzerland
	This work addresses the origins and the effects of the statistical dependence in non-Gaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that non-Gaussian heavy-tailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the x-y plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to non-Gaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.
	Slides WEA2C2 [1.249 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C2
About •	Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP02	Resonance Extraction Research Based on China Spallation Neutron Source	extraction, sextupole, kicker, lattice	397
	Y.W. An, L. Huang, Z.P. Li, S.Y. Xu, Y.S. Yuan IHEP, Beijing, People’s Republic of China
	Resonance extraction based on the RCS ring is an important aspect of beam applications. This article proposes a new design of resonance extraction based on the CSNS-RCS ring. By adjusting parameters such as the skew sextupole magnet, beam working point, RF-Kicker, etc., the simulation results from PyOrbit demonstrate the ability to rapidly extract a large number of protons within a few turns.
	Slides THAFP02 [1.497 MB]
	Poster THAFP02 [0.960 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP02
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
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THBP09	Pushing High Intensity and High Brightness Limits in the CERN PSB after the LIU Upgrades	brightness, space-charge, injection, emittance	458
	F. Asvesta, S.C.P. Albright, H. Bartosik, C. Bracco, G.P. Di Giovanni, T. Prebibaj CERN, Meyrin, Switzerland
	After the successful completion of the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) has produced beams with up to two times higher brightness. However, the efforts to continuously improve the beam quality for the CERN physics experiments are ongoing. In particular, the high brightness LHC beams show non-Gaussian tails in the transverse profiles that can cause losses in the downstream machines, and even at LHC injection. As a result, alternative production schemes based on triple harmonic capture are being investigated in order to preserve brightness and reduce transverse tails at the same time. In addition, in view of a possible upgrade to the ISOLDE facility that would require approximately twice the number of protons per ring, the ultimate intensity reach of the PSB is explored. In this context, injection schemes using painting both transversely and longitudinally in order to mitigate the strong space charge effects are developed.
	Poster THBP09 [0.751 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP09
About •	Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 20 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP14	LHC Optics Measurements from Transverse Damper for the High Intensity Frontier	dipole, optics, injection, operation	479
	T. Nissinen, F.S. Carlier, M. Le Garrec, E.H. Maclean, T.H.B. Persson, R. Tomás García, A. Wegscheider CERN, Meyrin, Switzerland
	Current and future accelerator projects are pushing the brightness and intensity frontier, creating new challenges for turn-by-turn based optics measurements. Transverse oscillations are limited in amplitude due to particle losses. The LHC Transverse Damper (ADT) is capable of generating low amplitude ac-dipole like transverse coherent beam oscillations. While the amplitude of such excitations is low, it is compensated by the excitation length of the ADT which, in theory, can last for up to 48h. Using the ADT, it is possible to use the maximum BPM acquisition length and improve the spectral resolution. First optics measurements have been performed using the ADT in the LHC in 2023, and the results are presented in this paper. Furthermore, some observed limitations of this method are presented and their impact on ADT studies are discussed.
	Poster THBP14 [2.632 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP14
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 25 October 2023
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THBP15	Optimizing Resonance Driving Terms Using MAD-NG Parametric Maps	optics, injection, octupole, emittance	483
	L. Deniau, S. Kostoglou, E.H. Maclean, K. Paraschou, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland
	In 2023, a review of the LHC octupolar resonance driving terms at injection was carried out, motivated by two observations: (i) unwanted losses during the injection process with strongly powered octupoles and (ii) an expected reduction in emittance growth from e-cloud effects in simulations with weaker octupolar resonances. The MAD-NG code was used to simultaneously optimise the main octupolar resonances: 4Qx, 4Qy, and 2Qx-2Qy by adjusting 16 quadrupole families and 16 octupole families, for a total of 32 parameters. These knobs were introduced as parameters in the transfer map, allowing the Jacobian required by the optimiser to be calculated in a single pass, saving 32 additional optics evaluations and avoiding finite difference approximations. Constraints on tunes, amplitude detuning and optics around the machine were also considered as part of the optimisation process. This paper reviews the parametric optimisation with MAD-NG and compares the results with MADX-PTC.
	Poster THBP15 [0.938 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP15
About •	Received ※ 02 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 October 2023
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THBP16	Emittance Growth From Electron Clouds Forming in the LHC Arc Quadrupoles	simulation, emittance, optics, electron	487
	K. Paraschou, H. Bartosik, L. Deniau, G. Iadarola, E.H. Maclean, L. Mether, Y. Papaphilippou, G. Rumolo, R. Tomás García CERN, Meyrin, Switzerland T. Pieloni, J.M.B. Potdevin EPFL, Lausanne, Switzerland
	Operation of the Large Hadron Collider with proton bunches spaced 25 ns apart favours the formation of electron clouds. In fact, a slow emittance growth is observed in proton bunches at injection energy (450 GeV), showing a bunch-by-bunch signature that is compatible with electron cloud effects. The study of these effects is particularly relevant in view of the planned HL-LHC upgrade, which relies on significantly increased beam intensity and brightness. Particle tracking simulations that take into account both electron cloud effects and the non-linear magnetic fields of the lattice suggest that the electron clouds forming in the arc quadrupoles are responsible for the observed degradation. In this work, the simulation results are studied to gain insight into the mechanism which drives the slow emittance growth. Finally, it is discussed how optimising the optics of the lattice can allow the mitigation of such effects.
	Poster THBP16 [3.432 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP16
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023
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THBP19	Experimental Investigations on the High-Intensity Effects Near the Half-Integer Resonance in the PSB	space-charge, experiment, emittance, brightness	499
	T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik CERN, Meyrin, Switzerland G. Franchetti GSI, Darmstadt, Germany
	Space charge effects are the main limitation for the brightness performance of the Proton Synchrotron Booster (PSB) at CERN. Following the upgrades of the LHC Injectors Upgrade (LIU) project, the PSB delivered unprecedented brightness even exceeding the projected target parameters. A possibility for further increasing the brightness is to operate above the half-integer resonance 2Q_y=9 in order to avoid emittance blow-up from resonances at Q_x,y=4 due to the strong space charge detuning. The half-integer resonance can be compensated to a great extent using the available quadrupole correctors in the PSB, and also deliberately excited in a controlled way. The control of the half-integer resonance and the flexibility of the PSB to create a variety of different beam and machine conditions allowed the experimental characterization of space charge effects near this resonance. This contribution reports the experimental observations of the particle trapping during the dynamic crossing of the half-integer, as well as systematic studies of the beam degradation from space charge induced resonance crossing.
	Poster THBP19 [3.077 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP19
About •	Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP20	Optics for Landau Damping with Minimized Octupolar Resonances in the LHC	optics, octupole, injection, focusing	503
	R. Tomás García, F.S. Carlier, L. Deniau, J. Dilly, J. Keintzel, S. Kostoglou, M. Le Garrec, E.H. Maclean, K. Paraschou, T.H.B. Persson, F. Soubelet, A. Wegscheider CERN, Meyrin, Switzerland
	Operation of the Large Hadron Collider (LHC) requires strong octupolar magnetic fields to suppress coherent beam instabilities. The amplitude detuning that is generated by these octupolar magnetic fields brings the tune of individual particles close to harmful resonances, which are mostly driven by the octupolar fields themselves. In 2023, new optics were deployed in the LHC at injection with optimized betatronic phase advances to minimize the resonances from the octupolar fields without affecting the amplitude detuning. This paper reports on the optics design, commissioning and the lifetime measurements performed to validate the optics.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP20
About •	Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
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THBP21	Increasing High Luminosity LHC Dynamic Aperture Using Optics Optimizations	optics, luminosity, dynamic-aperture, octupole	507
	R. De Maria, Y. Angelis, C.N. Droin, S. Kostoglou, F. Plassard, G. Sterbini, R. Tomás García CERN, Meyrin, Switzerland
	Funding: Work supported by the HL-LHC project. CERN’s Large Hadron Collider (LHC) is expected to operate with unprecedented beam current and brightness from the beginning of Run 4 in 2029. In the context of the High Luminosity LHC project, the baseline operational scenarios are currently being developed. They require a large octupole current and a large chromaticity throughout the entire cycle, which drives a strong reduction of dynamic aperture, in particular at injection and during the luminosity production phase. Despite being highly constrained, the LHC optics and sextupole and octupole corrector circuits still offer a few degrees of freedom that can be used to reduce resonances and the extent of the tune footprint at constant Landau damping, thereby leading to an improvement of the dynamic aperture. This contribution presents the status of the analysis that will be used to prepare the optics baseline for LHC Run 4.
	Poster THBP21 [1.286 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP21
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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THBP27	Experimental Investigation of Nonlinear Integrable Optics in a Paul Trap	lattice, octupole, experiment, space-charge	523
	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
	Funding: Work supported by Royal Society grants Octupoles are often used to damp beam instabilities caused by space charge. However, in general the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution to this problem is Quasi-Integrable Optics (QIO), where the octupoles are inserted between a specially designed lattice called a T-insert. An octupole with a strength that scales as 1/β³(s) is applied in the drift region to create a time-independent octupole field, leading to a lattice with an invariant Hamiltonian. This means that large tune spreads can be achieved without reducing the dynamic aperture. IBEX is a Paul trap which confines low energy ions with an RF voltage, simulating the transverse dynamics of an alternating gradient accelerator. IBEX has recently undergone an upgrade to allow for octupole fields to be created in the trap in addition to quadrupole focusing. We present our first experimental results from testing QIO with the IBEX trap. jake.flowerdew@physics.ox.ac.uk
	Poster THBP27 [4.163 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP27
About •	Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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FRA2I1	Summary of the Working Group A: Beam Dynamics in Rings	space-charge, experiment, simulation, impedance	662
	H. Bartosik, G. Rumolo CERN, Meyrin, Switzerland J.-L. Vay LBNL, Berkeley, California, USA N. Wang IHEP, Beijing, People’s Republic of China
	The HB-2023 workshop at CERN from October 9 to 13, 2023 is the continuation of the series of workshops, which started in 2002 at FNAL and rotates every two years between America, Europe and Asia. This contribution summarises the main highlights from Working Group A, Beam Dynamics in Rings, in terms of progress and challenges in the achievement of ever higher intensity and brightness hadron beams in accelerator rings around the world.
	Slides FRA2I1 [4.325 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I1
About •	Received ※ 04 December 2023 — Accepted ※ 05 December 2023 — Issued ※ 01 January 2024
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Paper

Title

Other Keywords

Page

MOA4I1

Design of a Fixed-Field Accelerating Ring for High Power Applications

injection, extraction, synchrotron, lattice

38

S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A fixed field accelerating ring (FFA) has some advantage to achieve high beam power over conventional ring accelerators. It would be also a sustainable option as future proton drivers. We will discuss the design of an FFA taking a future upgrade plan of ISIS (ISIS-II) as an example.

Slides MOA4I1 [14.313 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA4I1

About •

Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 15 October 2023 — Issued ※ 21 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUC3I3

Laser Stripping of H⁻ Beam

laser, experiment, injection, proton

141

T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A.R. Oguz
ORNL, Oak Ridge, Tennessee, USA
N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA
P.K. Saha
JAEA/J-PARC, Tokai-mura, Japan

Basic principles of laser assisted charge exchange injection for H⁻ ion andH⁰ beams are presented. Theoretical aspects of electromagnetic interaction of laser with hydrogen atom and H⁻ ions are discussed. Laser excitation, photoionizatio and interaction of atoms and ions with a strong electro-magnetic field are discussed and compared. Different techniques of LACE for stripping of high current stochastic beams are presented. The optimum parameters of LACE are estimated and compared for various ion beam energies. Experimental development of laser stripping at the SNS are reviewed. Future plans of LACE at the SNS and J-PARC are discussed.

Slides TUC3I3 [1.790 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC3I3

About •

Received ※ 04 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA1I2

Analytical and Numerical Studies on Kicked Beams in the Context of Half-Integer Studies

space-charge, coupling, emittance, damping

188

G. Franchetti
GSI, Darmstadt, Germany
F. Asvesta, H. Bartosik, T. Prebibaj
CERN, Meyrin, Switzerland

In the context of the half-integer studies an investigation of the dynamics of the kicked beam has revealed surprising properties. The coupling of space charge with chromatic- ity in addition to usual damping/non-damping dynamics, exhibits new properties typical of a linear coupling. This proceeding covers the status of these studies carried out with analytical and numerical approaches and the prelimi- nary results of experimental investigations in the CERN PS Booster.

Slides WEA1I2 [24.966 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA1I2

About •

Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 24 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2I1

Compensation of Third-order Resonances in the High Intensity Regime

sextupole, space-charge, operation, experiment

215

C.E. Gonzalez-Ortiz
MSU, East Lansing, Michigan, USA
R. Ainsworth
Fermilab, Batavia, Illinois, USA
P.N. Ostroumov
FRIB, East Lansing, Michigan, USA

As the Fermilab Accelerator Complex enters the high-intensity era, the Recycler Ring (RR) needs to mitigate the detrimental effect of third-order resonance crossing. Third-order resonance lines can be compensated to first order by cancelling out the global Resonance Driving Terms (RDTs) using the response matrix method. This compensation scheme has been proven to work at low intensities, i.e., in the single-particle regime. In order to evaluate the effectiveness of this compensation scheme at higher intensities, this study looks at dynamic and static tune scans, with and without resonance compensation, and different space charge tune shifts. Special care was taken in order to disentangle effects from space charge tune shift, structure resonances and space charge driven resonances.

Slides WEA2I1 [6.714 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I1

About •

Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 09 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2I2

Space Charge Induced Resonances and Suppression in J-PARC MR

optics, space-charge, simulation, operation

222

T. Yasui
KEK, Tokai, Ibaraki, Japan

In the main ring synchrotron (MR) of Japan Proton Accelerator Research Complex (J-PARC), space charge induced resonances are the cause of beam losses. Although we have scanned the tunes to minimize beam losses, it has been difficult to completely avoid high order structure resonances because the MR has only three super-periodicities. In the present settings for the neutrino operation, we identified that the space charge induced resonance 8ny=171 is the main source of beam losses, except for random resonances. We found that this resonance can be suppressed by beam optics modification while maintaining the tune. In this talk, we present the theoretical, simulation, and experimental results showing the advantages of the new beam optics and the reasons for them.

Slides WEA2I2 [6.189 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2I2

About •

Received ※ 07 November 2023 — Accepted ※ 18 November 2023 — Issued ※ 29 November 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2C1

Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS

space-charge, acceleration, ECR, simulation

228

S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang
IHEP, Beijing, People’s Republic of China

The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.

Slides WEA2C1 [4.710 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1

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Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023

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WEA2C2

Measurement of Transverse Statistical Dependence for Non-Gaussian Beam Distributions via Resonances in the CERN PSB

space-charge, experiment, factory, luminosity

231

E.R. Lamb, F. Asvesta, H. Bartosik, G. Sterbini
CERN, Meyrin, Switzerland
E.R. Lamb
EPFL, Lausanne, Switzerland

This work addresses the origins and the effects of the statistical dependence in non-Gaussian beam distributions with the ultimate goal to identify the most representative case for tracking simulations across the CERN accelerator complex. Starting from the observation that non-Gaussian heavy-tailed transverse beam profiles can be reconstructed from 4D phase space distributions under two different conditions (statistical independence or dependence in the x-y plane), we consider space charge dominated beams interacting with the lattice nonlinear resonances to perform measurements to study the mechanisms that lead to non-Gaussian distributions. Finally, we explore the beam dynamics implications of the above hypotheses in terms of dependent loss processes across the transverse planes.

Slides WEA2C2 [1.249 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C2

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Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

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THAFP02

Resonance Extraction Research Based on China Spallation Neutron Source

extraction, sextupole, kicker, lattice

397

Y.W. An, L. Huang, Z.P. Li, S.Y. Xu, Y.S. Yuan
IHEP, Beijing, People’s Republic of China

Resonance extraction based on the RCS ring is an important aspect of beam applications. This article proposes a new design of resonance extraction based on the CSNS-RCS ring. By adjusting parameters such as the skew sextupole magnet, beam working point, RF-Kicker, etc., the simulation results from PyOrbit demonstrate the ability to rapidly extract a large number of protons within a few turns.

Slides THAFP02 [1.497 MB]

Poster THAFP02 [0.960 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP02

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023

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THBP09

Pushing High Intensity and High Brightness Limits in the CERN PSB after the LIU Upgrades

brightness, space-charge, injection, emittance

458

F. Asvesta, S.C.P. Albright, H. Bartosik, C. Bracco, G.P. Di Giovanni, T. Prebibaj
CERN, Meyrin, Switzerland

After the successful completion of the LHC Injectors Upgrade (LIU) project, the CERN Proton Synchrotron Booster (PSB) has produced beams with up to two times higher brightness. However, the efforts to continuously improve the beam quality for the CERN physics experiments are ongoing. In particular, the high brightness LHC beams show non-Gaussian tails in the transverse profiles that can cause losses in the downstream machines, and even at LHC injection. As a result, alternative production schemes based on triple harmonic capture are being investigated in order to preserve brightness and reduce transverse tails at the same time. In addition, in view of a possible upgrade to the ISOLDE facility that would require approximately twice the number of protons per ring, the ultimate intensity reach of the PSB is explored. In this context, injection schemes using painting both transversely and longitudinally in order to mitigate the strong space charge effects are developed.

Poster THBP09 [0.751 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP09

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Received ※ 28 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 20 October 2023

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THBP14

LHC Optics Measurements from Transverse Damper for the High Intensity Frontier

dipole, optics, injection, operation

479

T. Nissinen, F.S. Carlier, M. Le Garrec, E.H. Maclean, T.H.B. Persson, R. Tomás García, A. Wegscheider
CERN, Meyrin, Switzerland

Current and future accelerator projects are pushing the brightness and intensity frontier, creating new challenges for turn-by-turn based optics measurements. Transverse oscillations are limited in amplitude due to particle losses. The LHC Transverse Damper (ADT) is capable of generating low amplitude ac-dipole like transverse coherent beam oscillations. While the amplitude of such excitations is low, it is compensated by the excitation length of the ADT which, in theory, can last for up to 48h. Using the ADT, it is possible to use the maximum BPM acquisition length and improve the spectral resolution. First optics measurements have been performed using the ADT in the LHC in 2023, and the results are presented in this paper. Furthermore, some observed limitations of this method are presented and their impact on ADT studies are discussed.

Poster THBP14 [2.632 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP14

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Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 25 October 2023

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THBP15

Optimizing Resonance Driving Terms Using MAD-NG Parametric Maps

optics, injection, octupole, emittance

483

L. Deniau, S. Kostoglou, E.H. Maclean, K. Paraschou, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland

In 2023, a review of the LHC octupolar resonance driving terms at injection was carried out, motivated by two observations: (i) unwanted losses during the injection process with strongly powered octupoles and (ii) an expected reduction in emittance growth from e-cloud effects in simulations with weaker octupolar resonances. The MAD-NG code was used to simultaneously optimise the main octupolar resonances: 4Qx, 4Qy, and 2Qx-2Qy by adjusting 16 quadrupole families and 16 octupole families, for a total of 32 parameters. These knobs were introduced as parameters in the transfer map, allowing the Jacobian required by the optimiser to be calculated in a single pass, saving 32 additional optics evaluations and avoiding finite difference approximations. Constraints on tunes, amplitude detuning and optics around the machine were also considered as part of the optimisation process. This paper reviews the parametric optimisation with MAD-NG and compares the results with MADX-PTC.

Poster THBP15 [0.938 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP15

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Received ※ 02 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 October 2023

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THBP16

Emittance Growth From Electron Clouds Forming in the LHC Arc Quadrupoles

simulation, emittance, optics, electron

487

K. Paraschou, H. Bartosik, L. Deniau, G. Iadarola, E.H. Maclean, L. Mether, Y. Papaphilippou, G. Rumolo, R. Tomás García
CERN, Meyrin, Switzerland
T. Pieloni, J.M.B. Potdevin
EPFL, Lausanne, Switzerland

Operation of the Large Hadron Collider with proton bunches spaced 25 ns apart favours the formation of electron clouds. In fact, a slow emittance growth is observed in proton bunches at injection energy (450 GeV), showing a bunch-by-bunch signature that is compatible with electron cloud effects. The study of these effects is particularly relevant in view of the planned HL-LHC upgrade, which relies on significantly increased beam intensity and brightness. Particle tracking simulations that take into account both electron cloud effects and the non-linear magnetic fields of the lattice suggest that the electron clouds forming in the arc quadrupoles are responsible for the observed degradation. In this work, the simulation results are studied to gain insight into the mechanism which drives the slow emittance growth. Finally, it is discussed how optimising the optics of the lattice can allow the mitigation of such effects.

Poster THBP16 [3.432 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP16

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 11 October 2023

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THBP19

Experimental Investigations on the High-Intensity Effects Near the Half-Integer Resonance in the PSB

space-charge, experiment, emittance, brightness

499

T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik
CERN, Meyrin, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Space charge effects are the main limitation for the brightness performance of the Proton Synchrotron Booster (PSB) at CERN. Following the upgrades of the LHC Injectors Upgrade (LIU) project, the PSB delivered unprecedented brightness even exceeding the projected target parameters. A possibility for further increasing the brightness is to operate above the half-integer resonance 2Q_y=9 in order to avoid emittance blow-up from resonances at Q_x,y=4 due to the strong space charge detuning. The half-integer resonance can be compensated to a great extent using the available quadrupole correctors in the PSB, and also deliberately excited in a controlled way. The control of the half-integer resonance and the flexibility of the PSB to create a variety of different beam and machine conditions allowed the experimental characterization of space charge effects near this resonance. This contribution reports the experimental observations of the particle trapping during the dynamic crossing of the half-integer, as well as systematic studies of the beam degradation from space charge induced resonance crossing.

Poster THBP19 [3.077 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP19

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Received ※ 30 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023

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THBP20

Optics for Landau Damping with Minimized Octupolar Resonances in the LHC

optics, octupole, injection, focusing

503

R. Tomás García, F.S. Carlier, L. Deniau, J. Dilly, J. Keintzel, S. Kostoglou, M. Le Garrec, E.H. Maclean, K. Paraschou, T.H.B. Persson, F. Soubelet, A. Wegscheider
CERN, Meyrin, Switzerland

Operation of the Large Hadron Collider (LHC) requires strong octupolar magnetic fields to suppress coherent beam instabilities. The amplitude detuning that is generated by these octupolar magnetic fields brings the tune of individual particles close to harmful resonances, which are mostly driven by the octupolar fields themselves. In 2023, new optics were deployed in the LHC at injection with optimized betatronic phase advances to minimize the resonances from the octupolar fields without affecting the amplitude detuning. This paper reports on the optics design, commissioning and the lifetime measurements performed to validate the optics.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP20

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Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023

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THBP21

Increasing High Luminosity LHC Dynamic Aperture Using Optics Optimizations

optics, luminosity, dynamic-aperture, octupole

507

R. De Maria, Y. Angelis, C.N. Droin, S. Kostoglou, F. Plassard, G. Sterbini, R. Tomás García
CERN, Meyrin, Switzerland

Funding: Work supported by the HL-LHC project.
CERN’s Large Hadron Collider (LHC) is expected to operate with unprecedented beam current and brightness from the beginning of Run 4 in 2029. In the context of the High Luminosity LHC project, the baseline operational scenarios are currently being developed. They require a large octupole current and a large chromaticity throughout the entire cycle, which drives a strong reduction of dynamic aperture, in particular at injection and during the luminosity production phase. Despite being highly constrained, the LHC optics and sextupole and octupole corrector circuits still offer a few degrees of freedom that can be used to reduce resonances and the extent of the tune footprint at constant Landau damping, thereby leading to an improvement of the dynamic aperture. This contribution presents the status of the analysis that will be used to prepare the optics baseline for LHC Run 4.

Poster THBP21 [1.286 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP21

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Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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THBP27

Experimental Investigation of Nonlinear Integrable Optics in a Paul Trap

lattice, octupole, experiment, space-charge

523

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

Funding: Work supported by Royal Society grants
Octupoles are often used to damp beam instabilities caused by space charge. However, in general the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution to this problem is Quasi-Integrable Optics (QIO), where the octupoles are inserted between a specially designed lattice called a T-insert. An octupole with a strength that scales as 1/β³(s) is applied in the drift region to create a time-independent octupole field, leading to a lattice with an invariant Hamiltonian. This means that large tune spreads can be achieved without reducing the dynamic aperture. IBEX is a Paul trap which confines low energy ions with an RF voltage, simulating the transverse dynamics of an alternating gradient accelerator. IBEX has recently undergone an upgrade to allow for octupole fields to be created in the trap in addition to quadrupole focusing. We present our first experimental results from testing QIO with the IBEX trap.
jake.flowerdew@physics.ox.ac.uk

Poster THBP27 [4.163 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP27

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Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023

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FRA2I1

Summary of the Working Group A: Beam Dynamics in Rings

space-charge, experiment, simulation, impedance

662

H. Bartosik, G. Rumolo
CERN, Meyrin, Switzerland
J.-L. Vay
LBNL, Berkeley, California, USA
N. Wang
IHEP, Beijing, People’s Republic of China

The HB-2023 workshop at CERN from October 9 to 13, 2023 is the continuation of the series of workshops, which started in 2002 at FNAL and rotates every two years between America, Europe and Asia. This contribution summarises the main highlights from Working Group A, Beam Dynamics in Rings, in terms of progress and challenges in the achievement of ever higher intensity and brightness hadron beams in accelerator rings around the world.

Slides FRA2I1 [4.325 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA2I1

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Received ※ 04 December 2023 — Accepted ※ 05 December 2023 — Issued ※ 01 January 2024

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