IPAC2022 - List of Authors (Torregrosa, C.)

Paper	Title	Page
TUPOTK063	CERN Linac4 Chopper Dump: Operational Experience and Future Upgrades	1370
	C.J. Sharp, P. Andreu Muñoz, M. Calviani, G. Costa, L.S. Esposito, R. Franqueira Ximenes, D. Grenier, E. Grenier-Boley, J.R. Hunt, A.M. Krainer, C.Y. Mucher, C. Torregrosa CERN, Meyrin, Switzerland
	The Chopper Dump in the Linac4 accelerator at CERN is a beam-intercepting device responsible for the absorption of the 3 MeV H⁻ ion beam produced by the Linac4 source and deflected upstream by an electromagnetic chopper. It allows a portion of the beam, which would otherwise fall into the unstable region of the radiofrequency buckets in the Proton Synchrotron Booster, to be dumped at low energy with minimal induced radiation. It may also be used to absorb the entire beam. With peak currents of 25 to 45 mA and shallow penetration, this results in large deposited energy densities, thermal gradients and mechanical stresses. Additional constraints arise from geometric integration, vacuum and radiation protection requirements. Material selection, beam-matter interaction studies and thermo-structural analyses are important aspects of the design process. The Chopper Dump underwent modification in 2019 following observed material degradation in the original version of the device. The experience gained, modifications made and observations noted since then are detailed herein. Against this background, the design and analysis of an upgraded device, intended to cope with future operational conditions, is outlined and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK063
About •	Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOTK049	Irradiation of Low-Z Carbon-Based Materials with 440 GeV/c Proton Beam for High Energy & Intensity Beam Absorbers: The CERN HiRadMat-56-HED Experiment	2883
	P. Andreu Muñoz, M. Calviani, N. Charitonidis, A. Cherif, E.M. Farina, A.M. Krainer, A. Lechner, J. Maestre, F.-X. Nuiry, R. Seidenbinder, C. Torregrosa CERN, Meyrin, Switzerland P. Simon TU Darmstadt, Darmstadt, Germany
	The beam stored energy and the peak intensity of CERN Large Hadron Collider (LHC) will grow in the next few years. The former will increase from the 320 MJ values of Run2 (2015-2018) to almost 540 MJ during Run3 (2022 onwards) and 680 MJ during the HL-LHC era putting stringent requirements on beam intercepting devices, such as absorbers and dumps. The HiRadMat-56-HED (High-Energy Dumps) experiment performed in Autumn 2021 executed at CERN HiRadMat facility employed the Super Proton Synchrotron accelerator (SPS) 440 GeV/c proton beam to impact different low-density carbon-based materials targets to assess their performance to these higher energy beam conditions. The study focused on advanced grades of graphitic materials, including isostatic graphite, carbon-fiber reinforced carbon and carbon-SiC materials in addition to flexible expanded graphite. Some of them specifically tailored in collaboration with industry to very specific properties. The objectives of this experiment are: (i) to assess the performance of existing and potentially suitable advanced materials for the currently operating LHC beam dumps and (ii) to study alternative materials for the HL-LHC main dump or for the Future Circular Collider dump systems. The contribution will detail the R&D phase during design, the execution of the experiment, the pre-irradiation tests as well as the first post irradiation examination of the target materials. Lessons learnt and impact on operational devices will also be drawn.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK049
About •	Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

CERN Linac4 Chopper Dump: Operational Experience and Future Upgrades

1370

C.J. Sharp, P. Andreu Muñoz, M. Calviani, G. Costa, L.S. Esposito, R. Franqueira Ximenes, D. Grenier, E. Grenier-Boley, J.R. Hunt, A.M. Krainer, C.Y. Mucher, C. Torregrosa
CERN, Meyrin, Switzerland

The Chopper Dump in the Linac4 accelerator at CERN is a beam-intercepting device responsible for the absorption of the 3 MeV H⁻ ion beam produced by the Linac4 source and deflected upstream by an electromagnetic chopper. It allows a portion of the beam, which would otherwise fall into the unstable region of the radiofrequency buckets in the Proton Synchrotron Booster, to be dumped at low energy with minimal induced radiation. It may also be used to absorb the entire beam. With peak currents of 25 to 45 mA and shallow penetration, this results in large deposited energy densities, thermal gradients and mechanical stresses. Additional constraints arise from geometric integration, vacuum and radiation protection requirements. Material selection, beam-matter interaction studies and thermo-structural analyses are important aspects of the design process. The Chopper Dump underwent modification in 2019 following observed material degradation in the original version of the device. The experience gained, modifications made and observations noted since then are detailed herein. Against this background, the design and analysis of an upgraded device, intended to cope with future operational conditions, is outlined and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK063

About •

Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022

Cite •

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

THPOTK049

Irradiation of Low-Z Carbon-Based Materials with 440 GeV/c Proton Beam for High Energy & Intensity Beam Absorbers: The CERN HiRadMat-56-HED Experiment

2883

P. Andreu Muñoz, M. Calviani, N. Charitonidis, A. Cherif, E.M. Farina, A.M. Krainer, A. Lechner, J. Maestre, F.-X. Nuiry, R. Seidenbinder, C. Torregrosa
CERN, Meyrin, Switzerland
P. Simon
TU Darmstadt, Darmstadt, Germany

The beam stored energy and the peak intensity of CERN Large Hadron Collider (LHC) will grow in the next few years. The former will increase from the 320 MJ values of Run2 (2015-2018) to almost 540 MJ during Run3 (2022 onwards) and 680 MJ during the HL-LHC era putting stringent requirements on beam intercepting devices, such as absorbers and dumps. The HiRadMat-56-HED (High-Energy Dumps) experiment performed in Autumn 2021 executed at CERN HiRadMat facility employed the Super Proton Synchrotron accelerator (SPS) 440 GeV/c proton beam to impact different low-density carbon-based materials targets to assess their performance to these higher energy beam conditions. The study focused on advanced grades of graphitic materials, including isostatic graphite, carbon-fiber reinforced carbon and carbon-SiC materials in addition to flexible expanded graphite. Some of them specifically tailored in collaboration with industry to very specific properties. The objectives of this experiment are: (i) to assess the performance of existing and potentially suitable advanced materials for the currently operating LHC beam dumps and (ii) to study alternative materials for the HL-LHC main dump or for the Future Circular Collider dump systems. The contribution will detail the R&D phase during design, the execution of the experiment, the pre-irradiation tests as well as the first post irradiation examination of the target materials. Lessons learnt and impact on operational devices will also be drawn.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK049

About •

Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022

Cite •

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