IPAC2019 - List of Authors (Gobbi, G.)

Paper	Title	Page
MOPRB048	Collimation System Studies for the FCC-hh	669
	R. Bruce, A. Abramov, A. Bertarelli, M.I. Besana, F. Carra, F. Cerutti, M. Fiascaris, G. Gobbi, A.M. Krainer, A. Lechner, A. Mereghetti, D. Mirarchi, J. Molson, M. Pasquali, S. Redaelli, D. Schulte, E. Skordis, M. Varasteh Anvar CERN, Meyrin, Switzerland A. Abramov JAI, Egham, Surrey, United Kingdom A. Faus-Golfe LAL, Orsay, France M. Serluca IN2P3-LAPP, Annecy-le-Vieux, France
	The Future Circular Collider (FCC-hh) is being designed as a 100 km ring that should collide 50 TeV proton beams. At 8.3 GJ, its stored beam energy will be a factor 28 higher than what has been achieved in the Large Hadron Collider, which has the highest stored beam energy among the colliders built so far. This puts unprecedented demands on the control of beam losses and collimation, since even a tiny beam loss risks quenching superconducting magnets. We present in this article the design of the FCC-hh collimation system and study the beam cleaning through simulations of tracking, energy deposition, and thermo-mechanical response. We investigate the collimation performance for design beam loss scenarios and potential bottlenecks are highlighted.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB048
About •	paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS091	Mechanical Robustness of HL-LHC Collimator Designs	1070
	F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis CERN, Meyrin, Switzerland
	Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project. Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS099	The Development Programme of Cathodes and Electron Guns for the Hollow Electron Lenses of the High Luminosity LHC Project	1102
	D. Perini, G. Gobbi CERN, Geneva, Switzerland D.J. Crawford, J. Ruan, G. Stancari, L.R. Valerio Fermilab, Batavia, Illinois, USA J. Feng, Z. Li, W. Shao, K. Zhang BVERI, Beijing, People’s Republic of China W. Liu, J. Wang, Y. Wang, Y. Yang Beijing University of Technology, Beijing, People’s Republic of China
	Funding: Research supported by the HL-LHC project The High Luminosity LHC project (HL-LHC) foresees the construction and installation of important new equipment to increase the performance of the LHC machine. The Hollow Electron Lens (HEL) is a promising system to control the beam halo. It improves the beam collimation system of the HL-LHC and mitigates possible equipment damage in case of failure scenarios from halo losses. The halo can store up to 30 MJ energy. The specifications for this new device are quite demanding. The source, an electron gun with an annular shaped cathode, has to deliver a current up to 5 A. This is five times higher than the current in the existing electron lenses in Fermi and Brookhaven national laboratories. This note describes the programme carried out to design and test high-perveance guns equipped with two types of high-performance scandate cathodes. The size of the final gun is now considerably smaller than the one of the first prototype, allowing a reduction of diameter and cost of the superconducting magnet system used to steer the electron beam. The tests carried out at FNAL, BVERI and BJUT demonstrated that the developed cathodes fulfil the specifications and can supply a 5 A fully Space Charge Limited (SCL) current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS099
About •	paper received ※ 17 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Collimation System Studies for the FCC-hh

669

R. Bruce, A. Abramov, A. Bertarelli, M.I. Besana, F. Carra, F. Cerutti, M. Fiascaris, G. Gobbi, A.M. Krainer, A. Lechner, A. Mereghetti, D. Mirarchi, J. Molson, M. Pasquali, S. Redaelli, D. Schulte, E. Skordis, M. Varasteh Anvar
CERN, Meyrin, Switzerland
A. Abramov
JAI, Egham, Surrey, United Kingdom
A. Faus-Golfe
LAL, Orsay, France
M. Serluca
IN2P3-LAPP, Annecy-le-Vieux, France

The Future Circular Collider (FCC-hh) is being designed as a 100 km ring that should collide 50 TeV proton beams. At 8.3 GJ, its stored beam energy will be a factor 28 higher than what has been achieved in the Large Hadron Collider, which has the highest stored beam energy among the colliders built so far. This puts unprecedented demands on the control of beam losses and collimation, since even a tiny beam loss risks quenching superconducting magnets. We present in this article the design of the FCC-hh collimation system and study the beam cleaning through simulations of tracking, energy deposition, and thermo-mechanical response. We investigate the collimation performance for design beam loss scenarios and potential bottlenecks are highlighted.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB048

About •

paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

MOPTS091

Mechanical Robustness of HL-LHC Collimator Designs

1070

F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis
CERN, Meyrin, Switzerland

Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project.
Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091

About •

paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

MOPTS099

The Development Programme of Cathodes and Electron Guns for the Hollow Electron Lenses of the High Luminosity LHC Project

1102

D. Perini, G. Gobbi
CERN, Geneva, Switzerland
D.J. Crawford, J. Ruan, G. Stancari, L.R. Valerio
Fermilab, Batavia, Illinois, USA
J. Feng, Z. Li, W. Shao, K. Zhang
BVERI, Beijing, People’s Republic of China
W. Liu, J. Wang, Y. Wang, Y. Yang
Beijing University of Technology, Beijing, People’s Republic of China

Funding: Research supported by the HL-LHC project
The High Luminosity LHC project (HL-LHC) foresees the construction and installation of important new equipment to increase the performance of the LHC machine. The Hollow Electron Lens (HEL) is a promising system to control the beam halo. It improves the beam collimation system of the HL-LHC and mitigates possible equipment damage in case of failure scenarios from halo losses. The halo can store up to 30 MJ energy. The specifications for this new device are quite demanding. The source, an electron gun with an annular shaped cathode, has to deliver a current up to 5 A. This is five times higher than the current in the existing electron lenses in Fermi and Brookhaven national laboratories. This note describes the programme carried out to design and test high-perveance guns equipped with two types of high-performance scandate cathodes. The size of the final gun is now considerably smaller than the one of the first prototype, allowing a reduction of diameter and cost of the superconducting magnet system used to steer the electron beam. The tests carried out at FNAL, BVERI and BJUT demonstrated that the developed cathodes fulfil the specifications and can supply a 5 A fully Space Charge Limited (SCL) current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS099

About •

paper received ※ 17 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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