HB2023 - List of Keywords (betatron)

Paper	Title	Other Keywords	Page
WEC2C1	Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation	collimation, heavy-ion, operation, simulation	236
	V. Rodin, R. Bruce, R. Cai, M. D’Andrea, L.S. Esposito, A. Lechner, J.B. Potoine, S. Redaelli, J. Schoofs CERN, Meyrin, Switzerland R. Cai EPFL, Lausanne, Switzerland J.B. Potoine IES, Montpellier, France
	The future LHC heavy-ion program, utilizing 208Pb⁸²⁺ beams at up to 7 Z TeV, is anticipated to operate with substantial intensity upgrade. During periods of short beam lifetime, a potential performance limitation may arise from secondary ions produced by electromagnetic dissociation and hadronic fragmentation in the collimators of the betatron cleaning insertion. These off-rigidity fragments risk quenching superconducting magnets when they are lost in the dispersion suppressor. To address this concern, an alternative collimation scheme will be introduced for forthcoming heavy ion runs, employing bent channeling crystals as primary collimators. In this contribution, we detail a thorough study of power deposition levels in superconducting magnets through FLUKA shower simulations in the crystal-based collimation system. The study focuses on the downstream dispersion suppressor regions of the betatron cleaning insertion, where the quench risk is the highest. Based on this work, we quantify the expected quench margin in future runs with 208Pb⁸²⁺ beams, providing crucial insights for the successful execution of the upgraded heavy-ion program at the HL-LHC. Research supported by the HL-LHC project.
	Slides WEC2C1 [3.105 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC2C1
About •	Received ※ 24 November 2023 — Revised ※ 25 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 16 January 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEC3C3	Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC	simulation, collimation, injection, optics	279
	N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken CERN, Meyrin, Switzerland
	The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.
	Slides WEC3C3 [1.641 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THC2I2	Extraction of LHC Beam Parameters from Schottky Signals	synchrotron, diagnostics, simulation, octupole	382
	K. Łasocha, D. Alves, C. Lannoy, N. Mounet CERN, Meyrin, Switzerland C. Lannoy, T. Pieloni EPFL, Lausanne, Switzerland
	Analysis of Schottky signals provides rich insights into the dynamics of a hadron beam, with well-established methods of deriving the betatron tune and machine chromaticity. In this contribution, we will report on recent developments in the analysis and understanding of the signals measured at the Large Hadron Collider during proton and Pb⁸²⁺ fills. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and compared with the previous methods. As a step beyond the classical theory of Schottky spectra, certain signal modifications due to the activity of the LHC machine systems will be discussed from the perspective of the applicability of the modified signal to the beam diagnostics.
	Slides THC2I2 [9.053 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2I2
About •	Received ※ 04 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP01	Probing Transverse Impedances in the High Frequency Range at the CERN SPS	impedance, simulation, optics, coupling	393
	E. de la Fuente, H. Bartosik, I. Mases Solé, G. Rumolo, C. Zannini CERN, Meyrin, Switzerland
	Funding: CERN The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of the Head-Tail mode zero instability. Since the SPS works above transition energy, the head tail mode zero is unstable for negative values of chromaticity. The measured instability growth rate is proportional to the real part of the transverse impedance. Studies performed after the LHC Injectors Upgrade (LIU) showed a relevant impedance around 2 GHz with high-gamma transition optics (Q26). This paper presents the follow-up studies to probe the behavior of this beam coupling impedance contribution.
	Slides THAFP01 [2.262 MB]
	Poster THAFP01 [1.149 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP01
About •	Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP10	A Linearized Vlasov Method for the Study of Transverse e-Cloud Instabilities	simulation, electron, quadrupole, dipole	462
	S. Johannesson, M. Seidel EPFL, Lausanne, Switzerland G. Iadarola CERN, Meyrin, Switzerland
	Using a Vlasov approach, electron cloud driven instabilities can be modeled to study beam stability on time scales that conventional Particle In Cell simulation methods cannot access. The Vlasov approach uses a linear description of electron cloud forces that accounts for both the betatron tune modulation along the bunch and the dipolar kicks from the electron cloud. Forces from electron clouds formed in quadrupole magnets as well as dipole magnets have been expressed in this formalism. In addition, the Vlasov approach can take into account the effect of chromaticity. To benchmark the Vlasov approach, it was compared with macroparticle simulations using the same linear description of electron cloud forces. The results showed good agreement between the Vlasov approach and macroparticle simulations for strong electron clouds, with both approaches showing a stabilizing effect from positive chromaticity. This stabilizing effect is consistent with observations from the LHC.
	Poster THBP10 [4.059 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP10
About •	Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP30	Linear Modelling and Lattice Correction from Betatron Phase Measurements at the Fermilab Recycler NOvA Ring	lattice, dipole, storage-ring, quadrupole	534
	M. Xiao, R. Ainsworth, K.J. Hazelwood, M.-J. Yang Fermilab, Batavia, Illinois, USA
	Utilizing the measurement of coherent betatron oscilla-tion phase has emerged as a fast and precise approach for identifying and rectifying errors in achieving a desired lattice in CESR (Cornell Electron Storage Ring), using TAO analysis program and BMAD subroutines. One key advantage of betatron phase measurement over ¿ meas-urement is its sensitivity to phase variations between detectors. This software package has been successfully implemented for the Recycler Ring at Fermilab, with the adaptation of different hardware installations. By em-ploying this technique, a linear model of the bare Recy-cler ring was established, enabling the correction of quadrupole errors.
	Poster THBP30 [1.476 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP30
About •	Received ※ 19 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 27 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP40	Mitigation Strategies for the Instabilities Induced by the Fundamental Mode of the HL-LHC Crab Cavities	cavity, impedance, feedback, optics	571
	L. Giacomel, P. Baudrenghien, X. Buffat, R. Calaga, N. Mounet CERN, Meyrin, Switzerland
	The transverse impedance is one of the potentially limiting effects for the performance of the High-Luminosity Large Hadron Collider (HL-LHC). In the current LHC, the impedance is dominated by the resistive-wall contribution of the collimators at typical bunch-spectrum frequencies, and is of broad-band nature. Nevertheless, the fundamental mode of the crab cavities, that are a vital part of the HL-LHC baseline, adds a strong and narrow-band contribution. The resulting coupled-bunch instability, which contains a strong head-tail component, requires dedicated mitigation measures, since the efficiency of the transverse damper is limited against such instabilities, and Landau damping from octupoles would not be sufficient. The efficiency and implications of various mitigation strategies, based on RF feedbacks and optics changes, are discussed, along with first measurements using crab cavity prototypes at the Super Proton Synchrotron (SPS).
	Poster THBP40 [0.461 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP40
About •	Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 19 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRC1I3	Devices for High-Efficiency Slow Extraction at J-PARC Main Ring	septum, extraction, proton, cathode	656
	R. Muto, T. Kimura, S. Murasugi, K. Numai, K. Okamura, Y. Shirakabe, M. Tomizawa, E. Yanaoka KEK, Ibaraki, Japan A. Matsumura Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan
	J-PARC Main Ring (MR) is a synchrotron that accelerates protons up to 30 GeV and supplies them to the Neutrino Experimental Facility and the Hadron Experimental Facility (HEF). Beam extraction from MR to HEF is performed by slow extraction using third-order resonance. In the slow extraction a device called an electrostatic septum (ESS) is used to scrape out the beam, and it is important to reduce the beam loss at the septum electrode of the ESS in order to supply a high-intensity beam. So far, we have achieved a slow extraction efficiency of 99.5% by developing an ESS with a thin septum electrode and tuning the bump orbit to reduce the width of the angular distribution of protons at the ESS. In addition, a collimator is installed downstream of the ESS to absorb particles scattered by the septum electrode, thereby reducing activation of the components downstream. In order to achieve further reduction of the beam loss, we are currently considering to install beam diffusers and/or bent silicon crystals at the upstream of the ESS. In this talk, we will present the current status of the slow extraction devices and future plans to further improve the extraction efficiency.
	Slides FRC1I3 [3.167 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRC1I3
About •	Received ※ 18 October 2023 — Revised ※ 19 October 2023 — Accepted ※ 23 October 2023 — Issued ※ 01 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

WEC2C1

Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation

collimation, heavy-ion, operation, simulation

236

V. Rodin, R. Bruce, R. Cai, M. D’Andrea, L.S. Esposito, A. Lechner, J.B. Potoine, S. Redaelli, J. Schoofs
CERN, Meyrin, Switzerland
R. Cai
EPFL, Lausanne, Switzerland
J.B. Potoine
IES, Montpellier, France

The future LHC heavy-ion program, utilizing 208Pb⁸²⁺ beams at up to 7 Z TeV, is anticipated to operate with substantial intensity upgrade. During periods of short beam lifetime, a potential performance limitation may arise from secondary ions produced by electromagnetic dissociation and hadronic fragmentation in the collimators of the betatron cleaning insertion. These off-rigidity fragments risk quenching superconducting magnets when they are lost in the dispersion suppressor. To address this concern, an alternative collimation scheme will be introduced for forthcoming heavy ion runs, employing bent channeling crystals as primary collimators. In this contribution, we detail a thorough study of power deposition levels in superconducting magnets through FLUKA shower simulations in the crystal-based collimation system. The study focuses on the downstream dispersion suppressor regions of the betatron cleaning insertion, where the quench risk is the highest. Based on this work, we quantify the expected quench margin in future runs with 208Pb⁸²⁺ beams, providing crucial insights for the successful execution of the upgraded heavy-ion program at the HL-LHC.
Research supported by the HL-LHC project.

Slides WEC2C1 [3.105 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC2C1

About •

Received ※ 24 November 2023 — Revised ※ 25 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 16 January 2024

Cite •

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

WEC3C3

Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC

simulation, collimation, injection, optics

279

N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken
CERN, Meyrin, Switzerland

The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.

Slides WEC3C3 [1.641 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3

About •

Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023

Cite •

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

THC2I2

Extraction of LHC Beam Parameters from Schottky Signals

synchrotron, diagnostics, simulation, octupole

382

K. Łasocha, D. Alves, C. Lannoy, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland

Analysis of Schottky signals provides rich insights into the dynamics of a hadron beam, with well-established methods of deriving the betatron tune and machine chromaticity. In this contribution, we will report on recent developments in the analysis and understanding of the signals measured at the Large Hadron Collider during proton and Pb⁸²⁺ fills. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and compared with the previous methods. As a step beyond the classical theory of Schottky spectra, certain signal modifications due to the activity of the LHC machine systems will be discussed from the perspective of the applicability of the modified signal to the beam diagnostics.

Slides THC2I2 [9.053 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THC2I2

About •

Received ※ 04 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 12 October 2023

Cite •

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

THAFP01

Probing Transverse Impedances in the High Frequency Range at the CERN SPS

impedance, simulation, optics, coupling

393

E. de la Fuente, H. Bartosik, I. Mases Solé, G. Rumolo, C. Zannini
CERN, Meyrin, Switzerland

Funding: CERN
The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of the Head-Tail mode zero instability. Since the SPS works above transition energy, the head tail mode zero is unstable for negative values of chromaticity. The measured instability growth rate is proportional to the real part of the transverse impedance. Studies performed after the LHC Injectors Upgrade (LIU) showed a relevant impedance around 2 GHz with high-gamma transition optics (Q26). This paper presents the follow-up studies to probe the behavior of this beam coupling impedance contribution.

Slides THAFP01 [2.262 MB]

Poster THAFP01 [1.149 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP01

About •

Received ※ 29 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023

Cite •

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

THBP10

A Linearized Vlasov Method for the Study of Transverse e-Cloud Instabilities

simulation, electron, quadrupole, dipole

462

S. Johannesson, M. Seidel
EPFL, Lausanne, Switzerland
G. Iadarola
CERN, Meyrin, Switzerland

Using a Vlasov approach, electron cloud driven instabilities can be modeled to study beam stability on time scales that conventional Particle In Cell simulation methods cannot access. The Vlasov approach uses a linear description of electron cloud forces that accounts for both the betatron tune modulation along the bunch and the dipolar kicks from the electron cloud. Forces from electron clouds formed in quadrupole magnets as well as dipole magnets have been expressed in this formalism. In addition, the Vlasov approach can take into account the effect of chromaticity. To benchmark the Vlasov approach, it was compared with macroparticle simulations using the same linear description of electron cloud forces. The results showed good agreement between the Vlasov approach and macroparticle simulations for strong electron clouds, with both approaches showing a stabilizing effect from positive chromaticity. This stabilizing effect is consistent with observations from the LHC.

Poster THBP10 [4.059 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP10

About •

Received ※ 26 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 14 October 2023

Cite •

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

THBP30

Linear Modelling and Lattice Correction from Betatron Phase Measurements at the Fermilab Recycler NOvA Ring

lattice, dipole, storage-ring, quadrupole

534

M. Xiao, R. Ainsworth, K.J. Hazelwood, M.-J. Yang
Fermilab, Batavia, Illinois, USA

Utilizing the measurement of coherent betatron oscilla-tion phase has emerged as a fast and precise approach for identifying and rectifying errors in achieving a desired lattice in CESR (Cornell Electron Storage Ring), using TAO analysis program and BMAD subroutines. One key advantage of betatron phase measurement over ¿ meas-urement is its sensitivity to phase variations between detectors. This software package has been successfully implemented for the Recycler Ring at Fermilab, with the adaptation of different hardware installations. By em-ploying this technique, a linear model of the bare Recy-cler ring was established, enabling the correction of quadrupole errors.

Poster THBP30 [1.476 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP30

About •

Received ※ 19 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 27 October 2023

Cite •

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

THBP40

Mitigation Strategies for the Instabilities Induced by the Fundamental Mode of the HL-LHC Crab Cavities

cavity, impedance, feedback, optics

571

L. Giacomel, P. Baudrenghien, X. Buffat, R. Calaga, N. Mounet
CERN, Meyrin, Switzerland

The transverse impedance is one of the potentially limiting effects for the performance of the High-Luminosity Large Hadron Collider (HL-LHC). In the current LHC, the impedance is dominated by the resistive-wall contribution of the collimators at typical bunch-spectrum frequencies, and is of broad-band nature. Nevertheless, the fundamental mode of the crab cavities, that are a vital part of the HL-LHC baseline, adds a strong and narrow-band contribution. The resulting coupled-bunch instability, which contains a strong head-tail component, requires dedicated mitigation measures, since the efficiency of the transverse damper is limited against such instabilities, and Landau damping from octupoles would not be sufficient. The efficiency and implications of various mitigation strategies, based on RF feedbacks and optics changes, are discussed, along with first measurements using crab cavity prototypes at the Super Proton Synchrotron (SPS).

Poster THBP40 [0.461 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP40

About •

Received ※ 30 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 19 October 2023

Cite •

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

FRC1I3

Devices for High-Efficiency Slow Extraction at J-PARC Main Ring

septum, extraction, proton, cathode

656

R. Muto, T. Kimura, S. Murasugi, K. Numai, K. Okamura, Y. Shirakabe, M. Tomizawa, E. Yanaoka
KEK, Ibaraki, Japan
A. Matsumura
Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan

J-PARC Main Ring (MR) is a synchrotron that accelerates protons up to 30 GeV and supplies them to the Neutrino Experimental Facility and the Hadron Experimental Facility (HEF). Beam extraction from MR to HEF is performed by slow extraction using third-order resonance. In the slow extraction a device called an electrostatic septum (ESS) is used to scrape out the beam, and it is important to reduce the beam loss at the septum electrode of the ESS in order to supply a high-intensity beam. So far, we have achieved a slow extraction efficiency of 99.5% by developing an ESS with a thin septum electrode and tuning the bump orbit to reduce the width of the angular distribution of protons at the ESS. In addition, a collimator is installed downstream of the ESS to absorb particles scattered by the septum electrode, thereby reducing activation of the components downstream. In order to achieve further reduction of the beam loss, we are currently considering to install beam diffusers and/or bent silicon crystals at the upstream of the ESS. In this talk, we will present the current status of the slow extraction devices and future plans to further improve the extraction efficiency.

Slides FRC1I3 [3.167 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRC1I3

About •

Received ※ 18 October 2023 — Revised ※ 19 October 2023 — Accepted ※ 23 October 2023 — Issued ※ 01 November 2023

Cite •

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