HB2023 - List of Authors (Bruce, R.)

Paper	Title	Page
TUC4C2	Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System	183
	B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider CERN, Meyrin, Switzerland
	Funding: Work supported by the HL-LHC project With High Luminosity Large Hadron Collider (HL-LHC) beam intensities, there are concerns that the beam losses in the dispersion suppressors around the betatron cleaning insertion might exceed the quench limits. Furthermore, to maximize the beam lifetime it is important to reduce the impedance as much as possible. The collimators constitute one of the main sources of impedance in HL-LHC, given the need to operate with small collimator gaps. To improve this, a new optics was developed which increases the beta function in the collimation area, as well as the single pass dispersion from the primary collimators to the downstream shower absorbers. Other possible improvements from orbit bumps, to further enhance the locally generated dispersion, and from asymmetric collimator settings were also studied. The new solutions were partially tested with 6.8 TeV beams at the LHC in a dedicated machine experiment in 2022. In this paper, the new performance is reviewed and prospects for future operational deployment are discussed.
	Slides TUC4C2 [2.222 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEC2C1	Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation	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	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)

THA1C1	High Intensity Beam Dynamics Challenges for HL-LHC	344
	N. Mounet, H. Bartosik, P. Baudrenghien, R. Bruce, X. Buffat, R. Calaga, R. De Maria, C.N. Droin, L. Giacomel, M. Giovannozzi, G. Iadarola, S. Kostoglou, B. Lindström, L. Mether, E. Métral, Y. Papaphilippou, K. Paraschou, S. Redaelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás García CERN, Meyrin, Switzerland
	The High Luminosity (HL-LHC) project aims to increase the integrated luminosity of CERN’s Large Hadron Collider (LHC) by an order of magnitude compared to its initial design. This requires a large increase in bunch intensity and beam brightness compared to the first LHC runs, and hence poses serious collective-effects challenges, related in particular to electron cloud, instabilities from beam-coupling impedance, and beam-beam effects. Here we present the associated constraints and the proposed mitigation measures to achieve the baseline performance of the upgraded LHC machine. We also discuss the interplay of these mitigation measures with other aspects of the accelerator, such as the physical and dynamic aperture, machine protection, magnet imperfections, optics, and the collimation system.
	Slides THA1C1 [3.385 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1C1
About •	Received ※ 01 October 2023 — Revised ※ 10 October 2023 — Accepted ※ 12 October 2023 — Issued ※ 15 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP08	Performance of the Ion Chain at the CERN Injector Complex and Transmission Studies During the 2023 Slip Stacking Commissioning	418
	M. Slupecki, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, T. Argyropoulos, H. Bartosik, P. Baudrenghien, G. Bellodi, M. Bozzolan, R. Bruce, C. Carli, J. Cenede, H. Damerau, A. Frassier, D. Gamba, G. Hagmann, A. Huschauer, V. Kain, G. Khatri, D. Küchler, A. Lasheen, K.S.B. Li, E. Mahner, G. Papotti, G. Piccinini, A. Rey, M. Schenk, R. Scrivens, A. Spierer, G. Tranquille, D. Valuch, F.M. Velotti, R. Wegner CERN, Meyrin, Switzerland E. Waagaard EPFL, Lausanne, Switzerland
	The 2023 run has been decisive for the LHC Ion Injector Complex. It demonstrated the capability of producing full trains of momentum slip stacked lead ions in the SPS. Slip stacking is a technique of interleaving particle trains, reducing the bunch spacing in SPS from 100 ns to 50 ns. It is needed to reach the total ion intensity requested by the HL-LHC project, as defined by updated common LIU/HL-LHC target beam parameters. This paper reviews the lead beam characteristics across the Ion Injector Complex, including transmission efficiencies up to the SPS extraction. It also documents the difficulties found during the commissioning and the solutions put in place.
	Slides THAFP08 [1.114 MB]
	Poster THAFP08 [1.995 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP08
About •	Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP18	Revised Collimation Configuration for the Updated FCC-hh Layout	495
	A. Abramov, R. Bruce, M. Giovannozzi, G. Pérez Segurana, S. Redaelli, T. Risselada CERN, Meyrin, Switzerland
	The collimation system for the hadron Future Circular Collider (FCC-hh) must handle proton beams with an unprecedented nominal beam energy and stored beam energy in excess of 8 GJ, and protect the superconducting magnets and other sensitive equipment while ensuring a high operational efficiency. The recent development of the 16-dipole lattice baseline for the FCC-hh, and the associated layout changes, has necessitated an adaptation of the collimation system. A revised configuration of the collimation system is presented, considering novel high-beta optics in the betatron collimation insertion. Performance is evaluated through loss map studies, with a focus on losses in critical areas, including collimation insertions and experimental interaction regions.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP18
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP49	Collimation of 400 MJ Beams at the LHC: The First Step Towards the HL-LHC Era	603
	S. Redaelli, A. Abramov, D.B. Baillard, R. Bruce, R. Cai, F. Carra, M. D’Andrea, M. Di Castro, L. Giacomel, P.D. Hermes, B. Lindström, D. Mirarchi, N. Mounet, F.-X. Nuiry, A. Perillo Marcone, F.F. Van der Veken CERN, Meyrin, Switzerland R. Cai EPFL, Lausanne, Switzerland A. Vella University of Malta, Information and Communication Technology, Msida, Malta
	Funding: Work supported by the HL-LHC project. An important upgrade programme is planned for the collimation system of the CERN Large Hadron Collider (LHC) in order to meet the challenges of the upcoming High-Luminosity LHC (HL-LHC) project. A first stage of the HL-LHC upgrade was already deployed during the last LHC Long Shutdown, offering important improvements of the collimation cleaning, a significant reduction of the impedance contribution and better cleaning of collisional debris, in particular for ion-ion collisions. This upgrade provides a critical opportunity to explore the LHC intensity limits during the LHC Run 3 and can provide crucial feedback to refine upgrade plans and operational scenarios in the HL-LHC era. This paper describes the performance of the upgraded LHC collimation system that has already enabled stored-beam energies larger than 400 MJ at the unprecedented beam energy of 6.8 TeV, and reviews further upgrade plans envisaged to reach 700 MJ beams at the HL-LHC.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP49
About •	Received ※ 03 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System

183

B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider
CERN, Meyrin, Switzerland

Funding: Work supported by the HL-LHC project
With High Luminosity Large Hadron Collider (HL-LHC) beam intensities, there are concerns that the beam losses in the dispersion suppressors around the betatron cleaning insertion might exceed the quench limits. Furthermore, to maximize the beam lifetime it is important to reduce the impedance as much as possible. The collimators constitute one of the main sources of impedance in HL-LHC, given the need to operate with small collimator gaps. To improve this, a new optics was developed which increases the beta function in the collimation area, as well as the single pass dispersion from the primary collimators to the downstream shower absorbers. Other possible improvements from orbit bumps, to further enhance the locally generated dispersion, and from asymmetric collimator settings were also studied. The new solutions were partially tested with 6.8 TeV beams at the LHC in a dedicated machine experiment in 2022. In this paper, the new performance is reviewed and prospects for future operational deployment are discussed.

Slides TUC4C2 [2.222 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2

About •

Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023

Cite •

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

WEC2C1

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

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

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)

THA1C1

High Intensity Beam Dynamics Challenges for HL-LHC

344

N. Mounet, H. Bartosik, P. Baudrenghien, R. Bruce, X. Buffat, R. Calaga, R. De Maria, C.N. Droin, L. Giacomel, M. Giovannozzi, G. Iadarola, S. Kostoglou, B. Lindström, L. Mether, E. Métral, Y. Papaphilippou, K. Paraschou, S. Redaelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás García
CERN, Meyrin, Switzerland

The High Luminosity (HL-LHC) project aims to increase the integrated luminosity of CERN’s Large Hadron Collider (LHC) by an order of magnitude compared to its initial design. This requires a large increase in bunch intensity and beam brightness compared to the first LHC runs, and hence poses serious collective-effects challenges, related in particular to electron cloud, instabilities from beam-coupling impedance, and beam-beam effects. Here we present the associated constraints and the proposed mitigation measures to achieve the baseline performance of the upgraded LHC machine. We also discuss the interplay of these mitigation measures with other aspects of the accelerator, such as the physical and dynamic aperture, machine protection, magnet imperfections, optics, and the collimation system.

Slides THA1C1 [3.385 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1C1

About •

Received ※ 01 October 2023 — Revised ※ 10 October 2023 — Accepted ※ 12 October 2023 — Issued ※ 15 October 2023

Cite •

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

THAFP08

Performance of the Ion Chain at the CERN Injector Complex and Transmission Studies During the 2023 Slip Stacking Commissioning

418

M. Slupecki, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, T. Argyropoulos, H. Bartosik, P. Baudrenghien, G. Bellodi, M. Bozzolan, R. Bruce, C. Carli, J. Cenede, H. Damerau, A. Frassier, D. Gamba, G. Hagmann, A. Huschauer, V. Kain, G. Khatri, D. Küchler, A. Lasheen, K.S.B. Li, E. Mahner, G. Papotti, G. Piccinini, A. Rey, M. Schenk, R. Scrivens, A. Spierer, G. Tranquille, D. Valuch, F.M. Velotti, R. Wegner
CERN, Meyrin, Switzerland
E. Waagaard
EPFL, Lausanne, Switzerland

The 2023 run has been decisive for the LHC Ion Injector Complex. It demonstrated the capability of producing full trains of momentum slip stacked lead ions in the SPS. Slip stacking is a technique of interleaving particle trains, reducing the bunch spacing in SPS from 100 ns to 50 ns. It is needed to reach the total ion intensity requested by the HL-LHC project, as defined by updated common LIU/HL-LHC target beam parameters. This paper reviews the lead beam characteristics across the Ion Injector Complex, including transmission efficiencies up to the SPS extraction. It also documents the difficulties found during the commissioning and the solutions put in place.

Slides THAFP08 [1.114 MB]

Poster THAFP08 [1.995 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP08

About •

Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023

Cite •

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

THBP18

Revised Collimation Configuration for the Updated FCC-hh Layout

495

A. Abramov, R. Bruce, M. Giovannozzi, G. Pérez Segurana, S. Redaelli, T. Risselada
CERN, Meyrin, Switzerland

The collimation system for the hadron Future Circular Collider (FCC-hh) must handle proton beams with an unprecedented nominal beam energy and stored beam energy in excess of 8 GJ, and protect the superconducting magnets and other sensitive equipment while ensuring a high operational efficiency. The recent development of the 16-dipole lattice baseline for the FCC-hh, and the associated layout changes, has necessitated an adaptation of the collimation system. A revised configuration of the collimation system is presented, considering novel high-beta optics in the betatron collimation insertion. Performance is evaluated through loss map studies, with a focus on losses in critical areas, including collimation insertions and experimental interaction regions.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP18

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023

Cite •

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

THBP49

Collimation of 400 MJ Beams at the LHC: The First Step Towards the HL-LHC Era

603

S. Redaelli, A. Abramov, D.B. Baillard, R. Bruce, R. Cai, F. Carra, M. D’Andrea, M. Di Castro, L. Giacomel, P.D. Hermes, B. Lindström, D. Mirarchi, N. Mounet, F.-X. Nuiry, A. Perillo Marcone, F.F. Van der Veken
CERN, Meyrin, Switzerland
R. Cai
EPFL, Lausanne, Switzerland
A. Vella
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Work supported by the HL-LHC project.
An important upgrade programme is planned for the collimation system of the CERN Large Hadron Collider (LHC) in order to meet the challenges of the upcoming High-Luminosity LHC (HL-LHC) project. A first stage of the HL-LHC upgrade was already deployed during the last LHC Long Shutdown, offering important improvements of the collimation cleaning, a significant reduction of the impedance contribution and better cleaning of collisional debris, in particular for ion-ion collisions. This upgrade provides a critical opportunity to explore the LHC intensity limits during the LHC Run 3 and can provide crucial feedback to refine upgrade plans and operational scenarios in the HL-LHC era. This paper describes the performance of the upgraded LHC collimation system that has already enabled stored-beam energies larger than 400 MJ at the unprecedented beam energy of 6.8 TeV, and reviews further upgrade plans envisaged to reach 700 MJ beams at the HL-LHC.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP49

About •

Received ※ 03 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023

Cite •

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