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Theory of bunched beam transverse Schottky signals with stationary rf system and high-order chromaticity
/ Lasocha, Kacper (CERN) ; Lannoy, Christophe (CERN ; LPHE, Lausanne) ; Mounet, Nicolas (CERN) ; Alves, Diogo (CERN)
The observation of transverse Schottky spectra provides insight into intrabunch particle dynamics and serves in numerous facilities to derive important beam and machine parameters, such as the betatron tune, first-order chromaticity, and transverse emittance. The original theory confirming the validity of these observations has been, however, developed by taking strong assumptions on the particle motion in both the longitudinal and transverse planes. [...]
2024 - 13 p.
- Published in : Phys. Rev. Accel. Beams 27 (2024) 112801
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2.
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Mitigation Strategies for the Instabilities Induced by the Fundamental Mode of the HL-LHC Crab Cavities
/ Giacomel, Lorenzo (CERN) ; Baudrenghien, Philippe (CERN) ; Buffat, Xavier (CERN) ; Calaga, Rama (CERN) ; Mounet, Nicolas (CERN)
The transverse impedance is one of the potentially limiting effects for the performance of the High-Luminosity Large Hadron Collider (HL-LHC). In the current LHC, the impedance is dominated by the resistive-wall contribution of the collimators at typical bunch-spectrum frequencies, and is of broad-band nature. [...]
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 571-574
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.571-574
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3.
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Impact of second-order chromaticity on the Schottky spectra of bunched beam
/ Lasocha, Kacper (CERN) ; Alves, Diogo (CERN) ; Lannoy, Christophe (CERN ; Ecole Polytechnique, Lausanne) ; Mounet, Nicolas (CERN)
Observation of Schottky signals provides information on important beam and machine parameters, such as transverse emittance, betatron tune, and first-order chromaticity. However, the so-far developed theory of Schottky spectra does not include the impact of the higher-order chromaticity, known to be non-negligible in the case of the Large Hadron Collider (LHC). [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) WEPG30
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEPG30
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4.
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Impact of octupoles on the Schottky spectra of bunched beams
/ Lannoy, Christophe (CERN ; Ecole Polytechnique, Lausanne) ; Alves, Diogo (CERN) ; Lasocha, Kacper (CERN) ; Mounet, Nicolas (CERN) ; Pieloni, Tatiana (Ecole Polytechnique, Lausanne)
Schottky monitors serve as non-invasive tools for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. However, octupole magnets commonly used in circular storage rings to mitigate instabilities through the Landau damping mechanism, can significantly affect the Schottky spectrum. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) WEPG32
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEPG32
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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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Status of beam-beam studies for the high-luminosity LHC
/ Droin, Colas (CERN) ; Sterbini, Guido (CERN) ; Efthymiopoulos, Ilias (CERN) ; Mounet, Nicolas (CERN) ; De Maria, Riccardo (CERN) ; Tomas, Rogelio (CERN) ; Kostoglou, Sofia (CERN)
Optimizing the configuration of an operational cycle of a collider such as the LHC is a complex process, requiring various simulation studies. In particular, Dynamic Aperture (DA) simulations, based on particle tracking, serve as indispensable tools for achieving this goal. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) THPC77
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.THPC77
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7.
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Experimental and simulated LHC Schottky spectra
/ Lannoy, Christophe (CERN ; Ecole Polytechnique, Lausanne) ; Alves, Diogo (CERN) ; Lasocha, Kacper (CERN) ; Mounet, Nicolas (CERN) ; Pieloni, Tatiana (Ecole Polytechnique, Lausanne)
Schottky monitors are valuable non-invasive tools used for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. This study investigates Schottky spectra at the Large Hadron Collider (LHC) through a combination of simulations and measurements. [...]
2024 - 4 p.
- Published in : JACoW IPAC 2024 (2024) WEPG31
Fulltext: PDF;
In : 15th International Particle Accelerator Conference (IPAC 2024), Nashville, TN, United States, 19 - 24 May 2024, pp.WEPG31
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8.
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Effect of Longitudinal Beam-Coupling Impedance on the Schottky Spectrum of Bunched Beams
/ Lannoy, Christophe (CERN ; Ecole Polytechnique, Lausanne) ; Alves, Diogo (CERN) ; Łasocha, Kacper (CERN) ; Mounet, Nicolas (CERN) ; Pieloni, Tatiana (Ecole Polytechnique, Lausanne)
Schottky spectra can be strongly affected by collective effects, in particular those arising from beam-coupling impedance when a large number of bunch charges are involved. In such conditions, the direct interpretation of the measured spectra becomes difficult, which prevents the extraction of beam and machine parameters in the same way as is usually done for lower bunch charges. [...]
2023 - 5 p.
- Published in : JACoW IBIC 2023 (2023) 428-432
Fulltext: PDF;
In : 12th International Beam Instrumentation Conference (IBIC 2023), Saskatoon, Canada, 10 - 14 Sep 2023, pp.428-432
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9.
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High intensity beam dynamics assessment and challenges for HL-LHC
/ Rumolo, G (CERN) ; Salvant, B (CERN) ; Mounet, N (CERN) ; Tomás, R (CERN) ; Bartosik, H (CERN) ; Baudrenghien, P (CERN) ; Bruce, R (CERN) ; Buffat, X (CERN) ; Calaga, R (CERN) ; De Maria, R (CERN) et al.
The High Luminosity (HL-LHC) project aims to increase the integrated luminosity of CERN’s Large Hadron Collider (LHC) by an order of magnitude compared to its initial design. This requires a large increase in bunch intensity and beam brightness compared to the first LHC runs, and hence poses serious collective-effects challenges, related in particular to electron cloud, instabilities from beam-coupling impedance, and beam-beam effects. [...]
2024 - 7 p.
- Published in : JINST
- Published in : JACoW HB: 2023 (2024) , pp. 344-350
Fulltext: PublicationJACoW - PDF; PublicationIOP - 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.T05016
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10.
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Studies on the Effect of Beam-Coupling Impedance on Schottky Spectra of Bunched Beams
/ Lannoy, Christophe (CERN ; EPFL, Lausanne, FSL) ; Alves, Diogo (CERN) ; Łasocha, Kacper (CERN) ; Mounet, Nicolas (CERN) ; Pieloni, Tatiana (Ecole Polytechnique, Lausanne)
Schottky monitors can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, in particular beam-coupling impedance, can significantly affect Schottky spectra when large bunch charges are involved. [...]
2024 - 4 p.
- Published in : JACoW HB 2023 (2024) 595-598
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.595-598
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