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Overview of beam intensity issues and mitigations in the CERN-SPS fast wire scanners
/ Veness, Raymond (CERN) ; Guerrero, Ana (CERN) ; Perez Fontenla, Ana Teresa (CERN) ; Harrison, Anthony (CERN) ; Salvant, Benoit (CERN) ; Zannini, Carlo (CERN) ; Antuono, Chiara (CERN) ; Vollinger, Christine (CERN) ; de la Fuente, Elena (CERN) ; Carra, Federico (CERN) et al.
A new design of fast wire scanner was installed in the CERN injector complex as part of the upgrades linked to the High-Luminosity LHC Project. Initial operations with these beams were good, but during the planned intensity ramp-up one early 2023, all four SPS scanners failed at the same time. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) WEPG26
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEPG26
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2.
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Impedance and thermal studies of the CERN SPS wire scanners and mitigation of wire heating
/ de la Fuente, Elena (CERN) ; Papazoglou, I (CERN) ; Sito, Leonardo (CERN) ; Andreazza, William (CERN) ; Antuono, Chiara (CERN) ; Bruchon, N (CERN) ; Calaga, Rama (CERN) ; Carra, Federico (CERN) ; Emery, J (CERN) ; Harrison, Anthony (CERN) et al.
All wires of the four CERN SPS rotational wirescanners broke when increasing the beam intensity towards the target for the LHC Injector Upgrade in 2023. Impedance and thermal studies were immediately launched, with simulations and measurements indicating that beam induced heating from resonant modes on the thin wire could be sufficient to cause these breakages. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) WEPG29
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEPG29
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Assessment of the real part of the impedance of the LHC collimators with instability growth rate measurements
/ Giacomel, Lorenzo (CERN) ; Lindstrom, Bjorn (CERN ; Royal Holloway, U. of London) ; Iadarola, Giovanni (CERN) ; Rumolo, Giovanni (CERN) ; Mounet, Nicolas (CERN) ; Bruce, Roderik (CERN) ; Buffat, Xavier (CERN)
The impedance of the Large Hadron Collider (LHC) is a source of instabilities and has to be monitored closely. It is usually assessed by measuring the tune-shift vs intensity, in particular at top energy where it is the most critical, as the collimators are the closest to the beam. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) THPC57
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.THPC57
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Understanding of the LHC warm vacuum module heating
/ Krkotic, Patrick (CERN) ; Baglin, Vincent (CERN) ; Chiggiato, Paolo (CERN) ; Papaphilippou, Yannis (CERN) ; Rumolo, Giovanni (CERN) ; Antuono, Chiara (CERN ; Rome U.) ; Bregliozzi, Giuseppe (CERN) ; Calatroni, Sergio (CERN) ; de la Fuente, Elena (CERN ; Madrid, Polytechnic U.) ; Galloro, Alessio (Calabria U. ; CERN) et al.
During the third run of the Large Hadron Collider in 2023, which had the highest intensity bunch population compared to previous runs, increased losses attributed to pressure spikes within a warm vacuum sector triggered a beam dump. Subsequent inspections revealed localised annealing and plasticisation of the tension spring in the sliding contact radio-frequency finger module, alongside traces of vapour deposition on the various module components with the stainless-steel spring material. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) TUAN3
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.TUAN3
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5.
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The electron cloud and its impact on LHC and future colliders
/ Mether, Lotta (CERN) ; Iadarola, Giovanni (CERN) ; Rumolo, Giovanni (CERN) ; Paraschou, Konstantinos (CERN) ; Sabato, Luca (Ecole Polytechnique, Lausanne) ; Johannesson, Sofia (Ecole Polytechnique, Lausanne)
The secondary emission of electrons and their interaction with the electromagnetic fields of charged particle beams can lead to the build-up of electron clouds in accelerator beam chambers. The interaction of the electrons with both the beam and the chamber walls leads to detrimental effects, such as transverse instabilities and emittance growth, beam loss, pressure rise and heat load. [...]
2024 - 6 p.
- Published in : JACoW IPAC 2024 (2024) WEZD2
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEZD2
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Understanding of the new horizontal instability at the PS Booster after LIU
/ Antuono, Chiara (Sapienza Universita e INFN, Roma I (IT)) ; Zannini, Carlo (CERN) ; Rumolo, Giovanni (CERN) ; Asvesta, Foteini (CERN) ; Migliorati, Mauro (Sapienza Universita e INFN, Roma I (IT))
Following the LHC Injectors Upgrade (LIU) project at CERN, the Proton Synchrotron Booster (PSB) has been upgraded to operate with a new injection kinetic energy of 160 MeV and an extraction energy of 2 GeV. To understand the performance of the accelerator in this new energy range, a series of measurements have been conducted, especially devoted to the beam stability to ensure the optimal operation of the machine. [...]
CERN-PBC-CONF-2024-010.-
Geneva : CERN, 2024 - 4.
- Published in : Link to proceedings
- Published in : JACoW: IPAC2024 (2024) , pp. WEPR44
pdf file: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.2594-2597
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Probing Transverse Impedances in the High Frequency Range at the CERN SPS
/ de la Fuente, Elena (CERN ; Tech. U. Madrid (main)) ; Bartosik, Hannes (CERN) ; Mases Solé, Ingrid (CERN ; Goethe U., Frankfurt (main)) ; Rumolo, Giovanni (CERN) ; Zannini, Carlo (CERN)
The SPS transverse impedance model, which includes the major impedance contributions in the machine, can be benchmarked through measurements of the Head-Tail mode zero instability. Since the SPS works above transition energy, the head tail mode zero is unstable for negative values of chromaticity. [...]
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 393-396
Fulltext: PDF;
In : 68th ICFA Advanced Beam Dynamics workshop on high-Intensity and High-Brightness Hadron Beams (HB 2023), CERN, Geneva, Switzerland, 9 - 13 Oct 2023, pp.393-396
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Electron Cloud Effects in the CERN Accelerators in Run 3
/ Mether, Lotta (CERN) ; Bartosik, Hannes (CERN) ; Giacomel, Lorenzo (CERN) ; Iadarola, Giovanni (CERN) ; Johannesson, Sofia (CERN) ; Mases Solé, Ingrid (CERN) ; Paraschou, Konstantinos (CERN) ; Rumolo, Giovanni (CERN) ; Sabato, Luca (CERN) ; Zannini, Carlo (CERN) et al.
Several of the machines in the CERN accelerator complex, in particular the Large Hadron Collider (LHC) and the Super Proton Synchrotron (SPS), are prone to the build-up of electron clouds. Electron cloud effects are observed especially when the machines are operated with a 25 ns bunch spacing, which has routinely been used in the LHC since the start of its second operational run in 2015. [...]
2024 - 5 p.
- Published in : JACoW HB 2023 (2024) 538-542
Fulltext: PDF;
In : 68th ICFA Advanced Beam Dynamics workshop on high-Intensity and High-Brightness Hadron Beams (HB 2023), CERN, Geneva, Switzerland, 9 - 13 Oct 2023, pp.538-542
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Emittance Growth From Electron Clouds Forming in the LHC Arc Quadrupoles
/ Paraschou, Konstantinos (CERN) ; Bartosik, Hannes (CERN) ; Deniau, Laurent (CERN) ; Iadarola, Giovanni (CERN) ; Maclean, Ewen (CERN) ; Mether, Lotta (CERN) ; Papaphilippou, Yannis (CERN) ; Pieloni, Tatiana (Ecole Polytechnique, Lausanne) ; Potdevin, Joséphine (Ecole Polytechnique, Lausanne) ; Rumolo, Giovanni (CERN) et al.
Operation of the Large Hadron Collider with proton bunches spaced 25 ns apart favours the formation of electron clouds. In fact, a slow emittance growth is observed in proton bunches at injection energy (450 GeV), showing a bunch-by-bunch signature that is compatible with electron cloud effects. [...]
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 487-490
Fulltext: PDF;
In : 68th ICFA Advanced Beam Dynamics workshop on high-Intensity and High-Brightness Hadron Beams (HB 2023), CERN, Geneva, Switzerland, 9 - 13 Oct 2023, pp.487-490
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Summary of the Working Group A: Beam Dynamics in Rings
/ Bartosik, Hannes (CERN) ; Rumolo, Giovanni (CERN) ; Vay, Jean-Luc (LBL, Berkeley) ; Wang, Na (Beijing, Inst. High Energy Phys.)
The HB-2023 workshop at CERN from October 9 to 13, 2023 is the continuation of the series of workshops, which started in 2002 at FNAL and rotates every two years between America, Europe and Asia. This contribution summarises the main highlights from Working Group A, Beam Dynamics in Rings, in terms of progress and challenges in the achievement of ever higher intensity and brightness hadron beams in accelerator rings around the world..
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 662-665
Fulltext: PDF;
In : 68th ICFA Advanced Beam Dynamics workshop on high-Intensity and High-Brightness Hadron Beams (HB 2023), CERN, Geneva, Switzerland, 9 - 13 Oct 2023, pp.662-665
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