IPAC2021 - List of Authors (Lechner, A.)

Paper	Title	Page
MOPAB001	Power Deposition in Superconducting Dispersion Suppressor Magnets Downstream of the Betatron Cleaning Insertion for HL-LHC	37
	A. Waets, C. Bahamonde Castro, E. Belli, R. Bruce, N. Fuster-Martínez, A. Lechner, A. Mereghetti, S. Redaelli, M. Sabaté-Gilarte, E. Skordis CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project The power deposited in dispersion suppressor magnets downstream of the Large Hadron Collider (LHC) betatron cleaning insertion is governed by off-momentum particles scattered out of the primary collimators. In order to mitigate the risk of magnet quenches during periods of short beam lifetime in future High-Luminosity (HL-LHC) operation, new dispersion suppressor (DS) collimators are considered for installation (one per beam). In this paper, we present FLUKA simulations for both protons and Pb ions at 7 TeV, predicting the power deposition in the DS magnets, including the new higher-field dipoles 11T which are needed to integrate the collimator in the cold region next to the cleaning insertion. The simulated power deposition levels for the adopted HL-LHC collimator configuration and settings are used to assess the quench margin by comparison with the present estimated quench levels.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB001
About •	paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 16 August 2021
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MOPAB002	Risk of Halo-Induced Magnet Quenches in the HL-LHC Beam Dump Insertion	41
	J.B. Potoine, A. Apollonio, E. Belli, C. Bracco, R. Bruce, M. D’Andrea, R. García Alía, A. Lechner, G. Lerner, S. Morales Vigo, S. Redaelli, V. Rizzoglio, E. Skordis, A. Waets CERN, Meyrin, Switzerland F. Wrobel IES, Montpellier, France
	Funding: Research supported by the HL-LHC project After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB002
About •	paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 22 August 2021
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WEXA06	Study of Pb-Pb and Pb-p Collision Debris in the CERN LHC in View of HL-LHC Operation	2528
	M. Sabaté-Gilarte, R. Bruce, F. Cerutti, A. Lechner CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project For the first time, a full characterization of the Pb-Pb and Pb-p collision debris as well as its impact in terms of energy deposition in the long straight section (LSS) of CERN’s Large Hadron Collider has been carried out. By means of Monte Carlo simulations with FLUKA, both inelastic nuclear interaction and electromagnetic dissociation were taken into account as source term for lead ion operation, while for Pb-p operation only nuclear interaction is of importance. The radiation exposure of detectors exclusively destined for ion beam runs is assessed, allowing drawing implications of their use. This work gave the opportunity for an unprecedented validation of simulation results against measurement of beam loss monitors (BLM) in the experimental LSS during ion operation. Pb-Pb operation refers to the 2018 ion run at 6.37 TeV per charge with a +160 microrad half crossing angle in the vertical plane at the ATLAS interaction point. Instead, Pb-p operation was benchmarked for the 2016 ion run at 6.5 TeV per charge with -140 microrad half crossing angle in the vertical plane at the same location.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA06
About •	paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021
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WEPAB361	New Generation CERN LHC Injection Dump - Assembly and Installation (TDIS)	3548
	D. Carbajo Perez, E. Berthomé, C. Bertone, N. Biancacci, C. Bracco, G. Bregliozzi, B. Bulat, C. Cadiou, M. Calviani, G. Cattenoz, A. Cherif, P. Costa Pinto, A. Dallocchio, M. Di Castro, P. Fessia, M.I. Frankl, R. Franqueira Ximenes, J.-F. Fuchs, H. Garcia Gavela, J.-M. Geisser, L. Gentini, S.S. Gilardoni, M.A. Gonzalez De La Aleja Cabana, J.L. Grenard, J.M. Heredia, S. Joly, A. Lechner, J. Lendaro, J. Maestre, E. Page, M. Perez Ornedo, A. Perillo-Marcone, D. Pugnat, E. Rigutto, B. Salvant, A. Sapountzis, K. Scibor, R. Seidenbinder, J. Sola Merino, M. Taborelli, E. Urrutia, A. Vieille, C. Vollinger, C. Yin Vallgren CERN, Geneva, Switzerland
	Funding: Work supported by the Hilumi Project During CERN’s LS2, several upgrades were performed to beam intercepting devices in the framework of the HL-LHC Project. Upgraded equipment includes two internal beam dumps (TDIS) intended for machine protection located at the injection points from the SPS to the LHC. These two devices have been assembled, tested, and installed around LHC Point 2 and Point 8 and are currently ready to get commissioned with the beam. They are 5.8m-long, three-module-segmented vacuum chambers, with large aperture to accommodate the injected and circulating beam and equipped with absorbing materials, These comprise graphite and higher Z alloys that are embedded on sub-assemblies reinforced with back-stiffeners made of TZM. The current contribution covers three main matters. First, it details the TDIS design and its key technical features. The second topic discussed is the outcome of an experiment where a prototype module was tested under high-energy beam impacts at CERN’s HiRadMat facility. To conclude it is presented the return of experience from the pre-series construction, validation and installation in the LHC tunnel.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB361
About •	paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021
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WEPAB368	Sigraflex® Studies for LHC CERN Beam Dump: Summary and Perspective	3571
	J.M. Heredia, M. Calviani, R. Franqueira Ximenes, D. Grenier, K. Kershaw, A. Lechner, P. Andreu-Muñoz, F.-X. Nuiry, A. Perillo-Marcone, V. Rizzoglio, C. Torregrosa CERN, Meyrin, Switzerland A. Alvaro SINTEF, Trondheim, Norway F. Berto, S. Solfiti NTNU, Trondheim, Norway
	The Large Hadron Collider (LHC) beam dump (TDE) is essential for safe and reliable operation of the collider. It absorbs particles extracted from the accelerator whenever required. The original design of the TDE dates from the mid 2000 and it is constituted of an eight-meter-long cylindrical stainless-steel tube, filled with low-Z carbon-based materials from different grades and densities. The Sigraflex®, an expanded low-density graphite, is employed in the middle section of the TDE core. Due to unexpected behaviour observed in the past LHC runs, several major upgrades were recently implemented in order for the TDE to be ready for LHC Run3 (2021-2024), where up to 555 MJ beam energy is expected to be dumped every few hours. According simulations, temperatures in the Sigraflex core will reach locally up to 1500°C in the regular dump cases, and above 2300°C for failure scenarios. The objective of this contribution is to summarize the LS2 hardware upgrades and the plan for the evaluation of the Sigraflex performance during LHC Run3. This work will also detail the last experimental and numerical findings applied to the Sigraflex®, and possible alternative materials for the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB368
About •	paper received ※ 18 May 2021 paper accepted ※ 11 August 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB031	Dump Line Layout and Beam Dilution Pattern Optimization of the Future Circular Collider	3815
	B. Facskó, D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary A. Lechner, E. Renner CERN, Meyrin, Switzerland
	To avoid any damage to the beam dump target in the Future Circular Collider, the beam will be swept over its surface using oscillating kickers in the x/y planes with a 90-degree phase difference, and an amplitude changing in time, creating a spiral pattern. The ideal pattern must have an increasing spiral pitch towards smaller radii to produce an even energy deposition density. We recommend the realization of the optimal pattern using two beating frequencies. This method enables a flat energy deposition density while only using simple independent damped oscillators. In this poster, we also present the study of the beamline optics and hardware that can realize the needed pattern. Two different possible hardware layouts were examined and optimized as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB031
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Power Deposition in Superconducting Dispersion Suppressor Magnets Downstream of the Betatron Cleaning Insertion for HL-LHC

37

A. Waets, C. Bahamonde Castro, E. Belli, R. Bruce, N. Fuster-Martínez, A. Lechner, A. Mereghetti, S. Redaelli, M. Sabaté-Gilarte, E. Skordis
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
The power deposited in dispersion suppressor magnets downstream of the Large Hadron Collider (LHC) betatron cleaning insertion is governed by off-momentum particles scattered out of the primary collimators. In order to mitigate the risk of magnet quenches during periods of short beam lifetime in future High-Luminosity (HL-LHC) operation, new dispersion suppressor (DS) collimators are considered for installation (one per beam). In this paper, we present FLUKA simulations for both protons and Pb ions at 7 TeV, predicting the power deposition in the DS magnets, including the new higher-field dipoles 11T which are needed to integrate the collimator in the cold region next to the cleaning insertion. The simulated power deposition levels for the adopted HL-LHC collimator configuration and settings are used to assess the quench margin by comparison with the present estimated quench levels.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB001

About •

paper received ※ 19 May 2021 paper accepted ※ 07 July 2021 issue date ※ 16 August 2021

Export •

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

MOPAB002

Risk of Halo-Induced Magnet Quenches in the HL-LHC Beam Dump Insertion

41

J.B. Potoine, A. Apollonio, E. Belli, C. Bracco, R. Bruce, M. D’Andrea, R. García Alía, A. Lechner, G. Lerner, S. Morales Vigo, S. Redaelli, V. Rizzoglio, E. Skordis, A. Waets
CERN, Meyrin, Switzerland
F. Wrobel
IES, Montpellier, France

Funding: Research supported by the HL-LHC project
After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB002

About •

paper received ※ 19 May 2021 paper accepted ※ 13 July 2021 issue date ※ 22 August 2021

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

WEXA06

Study of Pb-Pb and Pb-p Collision Debris in the CERN LHC in View of HL-LHC Operation

2528

M. Sabaté-Gilarte, R. Bruce, F. Cerutti, A. Lechner
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
For the first time, a full characterization of the Pb-Pb and Pb-p collision debris as well as its impact in terms of energy deposition in the long straight section (LSS) of CERN’s Large Hadron Collider has been carried out. By means of Monte Carlo simulations with FLUKA, both inelastic nuclear interaction and electromagnetic dissociation were taken into account as source term for lead ion operation, while for Pb-p operation only nuclear interaction is of importance. The radiation exposure of detectors exclusively destined for ion beam runs is assessed, allowing drawing implications of their use. This work gave the opportunity for an unprecedented validation of simulation results against measurement of beam loss monitors (BLM) in the experimental LSS during ion operation. Pb-Pb operation refers to the 2018 ion run at 6.37 TeV per charge with a +160 microrad half crossing angle in the vertical plane at the ATLAS interaction point. Instead, Pb-p operation was benchmarked for the 2016 ion run at 6.5 TeV per charge with -140 microrad half crossing angle in the vertical plane at the same location.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXA06

About •

paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

Export •

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

WEPAB361

New Generation CERN LHC Injection Dump - Assembly and Installation (TDIS)

3548

D. Carbajo Perez, E. Berthomé, C. Bertone, N. Biancacci, C. Bracco, G. Bregliozzi, B. Bulat, C. Cadiou, M. Calviani, G. Cattenoz, A. Cherif, P. Costa Pinto, A. Dallocchio, M. Di Castro, P. Fessia, M.I. Frankl, R. Franqueira Ximenes, J.-F. Fuchs, H. Garcia Gavela, J.-M. Geisser, L. Gentini, S.S. Gilardoni, M.A. Gonzalez De La Aleja Cabana, J.L. Grenard, J.M. Heredia, S. Joly, A. Lechner, J. Lendaro, J. Maestre, E. Page, M. Perez Ornedo, A. Perillo-Marcone, D. Pugnat, E. Rigutto, B. Salvant, A. Sapountzis, K. Scibor, R. Seidenbinder, J. Sola Merino, M. Taborelli, E. Urrutia, A. Vieille, C. Vollinger, C. Yin Vallgren
CERN, Geneva, Switzerland

Funding: Work supported by the Hilumi Project
During CERN’s LS2, several upgrades were performed to beam intercepting devices in the framework of the HL-LHC Project. Upgraded equipment includes two internal beam dumps (TDIS) intended for machine protection located at the injection points from the SPS to the LHC. These two devices have been assembled, tested, and installed around LHC Point 2 and Point 8 and are currently ready to get commissioned with the beam. They are 5.8m-long, three-module-segmented vacuum chambers, with large aperture to accommodate the injected and circulating beam and equipped with absorbing materials, These comprise graphite and higher Z alloys that are embedded on sub-assemblies reinforced with back-stiffeners made of TZM. The current contribution covers three main matters. First, it details the TDIS design and its key technical features. The second topic discussed is the outcome of an experiment where a prototype module was tested under high-energy beam impacts at CERN’s HiRadMat facility. To conclude it is presented the return of experience from the pre-series construction, validation and installation in the LHC tunnel.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB361

About •

paper received ※ 18 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021

Export •

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

WEPAB368

Sigraflex® Studies for LHC CERN Beam Dump: Summary and Perspective

3571

J.M. Heredia, M. Calviani, R. Franqueira Ximenes, D. Grenier, K. Kershaw, A. Lechner, P. Andreu-Muñoz, F.-X. Nuiry, A. Perillo-Marcone, V. Rizzoglio, C. Torregrosa
CERN, Meyrin, Switzerland
A. Alvaro
SINTEF, Trondheim, Norway
F. Berto, S. Solfiti
NTNU, Trondheim, Norway

The Large Hadron Collider (LHC) beam dump (TDE) is essential for safe and reliable operation of the collider. It absorbs particles extracted from the accelerator whenever required. The original design of the TDE dates from the mid 2000 and it is constituted of an eight-meter-long cylindrical stainless-steel tube, filled with low-Z carbon-based materials from different grades and densities. The Sigraflex®, an expanded low-density graphite, is employed in the middle section of the TDE core. Due to unexpected behaviour observed in the past LHC runs, several major upgrades were recently implemented in order for the TDE to be ready for LHC Run3 (2021-2024), where up to 555 MJ beam energy is expected to be dumped every few hours. According simulations, temperatures in the Sigraflex core will reach locally up to 1500°C in the regular dump cases, and above 2300°C for failure scenarios. The objective of this contribution is to summarize the LS2 hardware upgrades and the plan for the evaluation of the Sigraflex performance during LHC Run3. This work will also detail the last experimental and numerical findings applied to the Sigraflex®, and possible alternative materials for the future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB368

About •

paper received ※ 18 May 2021 paper accepted ※ 11 August 2021 issue date ※ 16 August 2021

Export •

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

THPAB031

Dump Line Layout and Beam Dilution Pattern Optimization of the Future Circular Collider

3815

B. Facskó, D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
A. Lechner, E. Renner
CERN, Meyrin, Switzerland

To avoid any damage to the beam dump target in the Future Circular Collider, the beam will be swept over its surface using oscillating kickers in the x/y planes with a 90-degree phase difference, and an amplitude changing in time, creating a spiral pattern. The ideal pattern must have an increasing spiral pitch towards smaller radii to produce an even energy deposition density. We recommend the realization of the optimal pattern using two beating frequencies. This method enables a flat energy deposition density while only using simple independent damped oscillators. In this poster, we also present the study of the beamline optics and hardware that can realize the needed pattern. Two different possible hardware layouts were examined and optimized as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB031

About •

paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021

Export •

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