1.
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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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2.
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Refining the LHC Longitudinal Impedance Model
/ Zampetakis, Michail (CERN) ; Argyropoulos, Theodoros (CERN) ; Brischetto, Ylenia (CERN) ; Calaga, Rama (CERN) ; Giacomel, Lorenzo (CERN) ; Karlsen-Bæck, Birk Emil (INFN, Rome ; Rome U. ; CERN) ; Karpov, Ivan (CERN) ; Mounet, Nicolas (CERN) ; Salvant, Benoit (CERN) ; Timko, Helga (CERN)
Modelling the longitudinal impedance for the Large Hadron Collider (LHC) has been a long-standing effort, especially in view of its High-Luminosity (HL) upgrade. The resulting impedance model is an essential input for beam dynamics studies. [...]
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 559-562
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.559-562
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3.
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Numerical methods for emittance computation from luminosity
/ Rufolo, Matteo (Dalle Molle Inst. AI Studies, Lugano) ; Fornara, Andrea (Manchester U. ; CERN) ; Lamb, Elleanor (Ecole Polytechnique, Lausanne ; CERN) ; Sterbini, Guido (CERN) ; Giacomel, Lorenzo (CERN)
The beam transverse emittances play a critical role in high-energy colliders. Various measurement techniques are employed to measure them. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) MOPC19
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.MOPC19
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4.
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Impedance analysis of deformable RF contact bridges for high luminosity LHC
/ Krkotic, P (CERN) ; Calatroni, S (CERN) ; Neroni, M (CERN) ; Völlinger, C (CERN) ; Salvant, B (CERN) ; Baglin, V (CERN) ; Garion, C (CERN) ; Bregliozzi, G (CERN)
In order to maintain the continuity of the vacuum system wall and comply with beam stability limits, radio frequency contact bridges are utilised as transitional elements in beam vacuum line interconnections. These radio frequency contact bridges must absorb and correct longitudinal, angular, and transverse misalignments brought on by mechanical motions during assembly, alignment, operating phases and thermal influences during accelerator operation. [...]
2023 - 4 p.
- Published in : JACoW IPAC 2023 (2023) WEPL153
Fulltext: PDF;
In : 14th International Particle Accelerator Conference (IPAC 2023), Venice, Italy, 7 - 12 May 2023, pp.WEPL153
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5.
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A Novel Method for Transverse Beam-Coupling Impedance Measurements in Particle Accelerator Devices Using the Bead-Pull Method
/ Antuono, Chiara (U. Rome La Sapienza (main) ; CERN) ; Sito, Leonardo (CERN ; Naples U.) ; Calzone, Eleonora (U. Rome La Sapienza (main) ; CERN) ; el Dali, D (CERN) ; Migliorati, Mauro (CERN ; U. Rome La Sapienza (main)) ; Mostacci, Andrea (CERN ; U. Rome La Sapienza (main)) ; Fienga, Francesco (CERN ; Naples U.) ; Marrazzo, Vincenzo Romano (CERN ; Naples U.) ; Breglio, Giovanni (CERN ; Naples U.) ; Rumolo, G (CERN) et al.
In high-energy particle accelerators, circulating particle beams with high intensity interact electromagnetically with their surroundings (i.e., metallic vacuum chambers of various geometries). These electromagnetic interactions, which are typically described through the concept of beam-coupling impedance, can represent a serious issue in terms of stability of the particle beam and heating on the accelerator structures. [...]
2024 - 9 p.
- Published in : IEEE Trans. Instrum. Meas. 73 (2024) 8005209
Fulltext: PDF;
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6.
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10.17181/CERN.4W8R.NSGX
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7.
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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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8.
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Impedance modelling and collective effects in the Future Circular e$^{+}$e$^{−}$ Collider with 4 IPs
/ Migliorati, M. (U. Rome La Sapienza (main) ; INFN, Rome) ; Antuono, C. (INFN, Rome ; U. Rome La Sapienza (main) ; CERN) ; Carideo, E. (U. Rome La Sapienza (main) ; INFN, Rome ; CERN) ; Zhang, Y. (Beijing, Inst. High Energy Phys.) ; Zobov, M. (LNF, Dafne Light)
The FCC-ee impedance model is being constantly updated closely following the vacuum chamber design and parameters evolution. In particular, at present, a thicker NEG coating of 150 nm (instead of previous 100 nm) has been suggested by the vacuum experts, and a more realistic impedance model of the bellows has been investigated. [...]
arXiv:2204.04616.-
2022-08-25 - 16 p.
- Published in : EPJ Tech. Instrum. 9 (2022) 10
Fulltext: document - PDF; 2204.04616 - PDF;
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9.
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Electron Beam Characterization of REBCO-Coated Conductors at Cryogenic Conditions
/ Haubner, Michal (CERN ; Prague, Tech. U.) ; Krkotic, Patrick (CERN) ; Serafim, Catarina (CERN ; Helsinki U.) ; Petit, Valentine (CERN) ; Baglin, Vincent (CERN) ; Calatroni, Sergio (CERN) ; Henrist, Bernard (CERN) ; Romanov, Artur (Barcelona, Autonoma U.) ; Puig, Teresa (Barcelona, Autonoma U.) ; Gutierrez, Joffre (Barcelona, Autonoma U.)
Particle accelerators with superconducting magnets operating at cryogenic temperatures use a beam screen (BS) liner that extracts heat generated by the circulating bunched charge particle beam before it can reach the magnets. The BS surface, commonly made of high-conductivity copper, provides a low impedance for beam stability reasons, low secondary electron yield (SEY)to mitigate the electron-cloud (EC) effect, and low electron-stimulated desorption yield (ESD) to limit the dynamic pressure rise due to EC. [...]
arXiv:2410.00770.-
2023-02-21 - 15 p.
- Published in : Appl. Sciences 13 (2023) 2765
Fulltext: 2410.00770 - PDF; document - PDF;
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10.
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Evaluation of the impact of REBCO-coated conductors on the resistive wall impedance of the FCC-hh
/ Tagdulang, N D (CELLS - ALBA, LLS) ; Günzel, T (CELLS - ALBA, LLS) ; Pont, M (CELLS - ALBA, LLS) ; Krkotic, P (CERN) ; O'Callaghan, J M (Barcelona, Polytechnic U.)
The beam screen for the Future Circular hadron-hadron Collider (FCC-hh) has a baseline design based on a copper (Cu) coating. Calculations have indicated that the resistive wall impedance will be the major contributor to the beam impedance for the FCC-hh at both injection and collision and that Cu might be on the limit to ensure beam stability. [...]
2023 - 4 p.
- Published in : JACoW IPAC 2023 (2023) WEPL135
Fulltext: PDF;
In : 14th International Particle Accelerator Conference (IPAC 2023), Venice, Italy, 7 - 12 May 2023, pp.WEPL135
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