HB2023 - List of Authors (Lechner, A.)

Paper	Title	Page
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)

THBP17	Transverse Coherent Instability Studies for the High-Energy Part of the Muon Collider Complex	491
	D. Amorim, F. Batsch, L. Bottura, D. Calzolari, C. Carli, H. Damerau, A. Grudiev, A. Lechner, E. Métral, D. Schulte, K. Skoufaris CERN, Meyrin, Switzerland A. Chancé CEA-DRF-IRFU, France T. Pieloni EPFL, Lausanne, Switzerland
	Funding: This project has received funding from the European Union¿s Research and Innovation programme under GA No 101094300 and the Swiss Accelerator Research and Technology (CHART) program (www.chart.ch). The International Muon Collider Collaboration (IMCC) is studying a 3 TeV center-of-mass muon collider ring, as well as a possible next stage at 10 TeV. Muons being 200 times heavier than electrons, limitations from synchrotron radiation are mostly suppressed, but the muon decay drives the accelerator chain design. After the muon and anti-muon bunches are produced and 6D cooled, a series of Linac, recirculating Linac and Rapid Cycling Synchrotron (RCS) quickly accelerate the bunches before the collider ring. A large number of RF cavities are required in the RCS to ensure that over 90% of the muons survive in each ring. The effects of cavities higher-order modes on transverse coherent stability have been looked at in detail, including the one of a bunch offset in the cavities, along with possible mitigation measures. In the collider ring, the decay of high-energy muons is a challenge for heat load management and radiation shielding. A tungsten liner would protect the superconducting magnet from decay products. Impedance and related beam stability have been investigated to identify the minimum vacuum chamber radius and transverse damper properties required for stable beams.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP17
About •	Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 01 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP58	Advancing Beam Energy Absorption in the Large Hadron Collider: Evolution of Beam Dumps Design and Operation From LHC Construction to High Luminosity LHC
	M. Calviani, A.P. Bernardes, C. Bracco, E.M. Farina, R. Franqueira Ximenes, D. Grenier, E. Grenier-Boley, K. Kershaw, A. Lechner, A. Perillo, N. Solieri CERN, Meyrin, Switzerland
	Two 6-tonne beam dumps are employed to absorb the energy of the two Large Hadron Collider (LHC) intense 7 TeV/c proton beams. Originally designed to handle approximately 300 MJ of energy deposited per dump event, the capacity of these dumps has grown over the lifespan of the LHC due to upgrades aimed at enhancing the machine’s scientific potential. In the era of the High Luminosity LHC (HL-LHC), the dumps will need to withstand energy absorptions of up to 700 MJ per dump. Several upgrades and interventions, such as adjustments to the outer vessel and supporting structure as well as enhancements to online instrumentation, have been executed since the initial installation of the beam dumps. In addition, significant advancements in simulation techniques have been implemented to gain a deeper understanding of the intricate dynamics of high-energy beam absorption and the resulting thermo-mechanical repercussions. Lessons learnt have been acquired also thanks to a first-of-a-kind autopsy. This contribution will present a comprehensive overview of the design, operational experiences, and evolutionary journey of the main absorber within the Large Hadron Collider.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

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)

THBP17

Transverse Coherent Instability Studies for the High-Energy Part of the Muon Collider Complex

491

D. Amorim, F. Batsch, L. Bottura, D. Calzolari, C. Carli, H. Damerau, A. Grudiev, A. Lechner, E. Métral, D. Schulte, K. Skoufaris
CERN, Meyrin, Switzerland
A. Chancé
CEA-DRF-IRFU, France
T. Pieloni
EPFL, Lausanne, Switzerland

Funding: This project has received funding from the European Union¿s Research and Innovation programme under GA No 101094300 and the Swiss Accelerator Research and Technology (CHART) program (www.chart.ch).
The International Muon Collider Collaboration (IMCC) is studying a 3 TeV center-of-mass muon collider ring, as well as a possible next stage at 10 TeV. Muons being 200 times heavier than electrons, limitations from synchrotron radiation are mostly suppressed, but the muon decay drives the accelerator chain design. After the muon and anti-muon bunches are produced and 6D cooled, a series of Linac, recirculating Linac and Rapid Cycling Synchrotron (RCS) quickly accelerate the bunches before the collider ring. A large number of RF cavities are required in the RCS to ensure that over 90% of the muons survive in each ring. The effects of cavities higher-order modes on transverse coherent stability have been looked at in detail, including the one of a bunch offset in the cavities, along with possible mitigation measures. In the collider ring, the decay of high-energy muons is a challenge for heat load management and radiation shielding. A tungsten liner would protect the superconducting magnet from decay products. Impedance and related beam stability have been investigated to identify the minimum vacuum chamber radius and transverse damper properties required for stable beams.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP17

About •

Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 01 November 2023

Cite •

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

THBP58

Advancing Beam Energy Absorption in the Large Hadron Collider: Evolution of Beam Dumps Design and Operation From LHC Construction to High Luminosity LHC

M. Calviani, A.P. Bernardes, C. Bracco, E.M. Farina, R. Franqueira Ximenes, D. Grenier, E. Grenier-Boley, K. Kershaw, A. Lechner, A. Perillo, N. Solieri
CERN, Meyrin, Switzerland

Two 6-tonne beam dumps are employed to absorb the energy of the two Large Hadron Collider (LHC) intense 7 TeV/c proton beams. Originally designed to handle approximately 300 MJ of energy deposited per dump event, the capacity of these dumps has grown over the lifespan of the LHC due to upgrades aimed at enhancing the machine’s scientific potential. In the era of the High Luminosity LHC (HL-LHC), the dumps will need to withstand energy absorptions of up to 700 MJ per dump. Several upgrades and interventions, such as adjustments to the outer vessel and supporting structure as well as enhancements to online instrumentation, have been executed since the initial installation of the beam dumps. In addition, significant advancements in simulation techniques have been implemented to gain a deeper understanding of the intricate dynamics of high-energy beam absorption and the resulting thermo-mechanical repercussions. Lessons learnt have been acquired also thanks to a first-of-a-kind autopsy. This contribution will present a comprehensive overview of the design, operational experiences, and evolutionary journey of the main absorber within the Large Hadron Collider.

Cite •

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