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Articles by Ewen Hamish
Report from LHC MD 6863: Amplitude Detuning Corrections from Feed-Down
Home > Articles & Preprints > CERN Notes > Accelerators & Technology Sector Notes > Report from LHC MD 6863: Amplitude Detuning Corrections from Feed-Down Report number CERN-ACC-NOTE-2023-0028 Title Report from LHC MD 6863: Amplitude Detuning Corrections from Feed-Down If you experience any problem watching the video, click the download button below Author(s) Dilly, Joschua Werner (CERN) ; Le Garrec, Mael (Goethe University Frankfurt (DE)) ; Maclean, Ewen Hamish (CERN) ; Van Riesen-Haupt,...
MD6864 — Decapole studies at injection
Home > Articles & Preprints > CERN Notes > Accelerators & Technology Sector Notes > MD6864 — Decapole studies at injection Report number CERN-ACC-NOTE-2023-0018 Title MD6864 — Decapole studies at injection If you experience any problem watching the video, click the download button below Author(s) Le Garrec, Mael (Goethe University Frankfurt (DE)) ; Carlier, Felix Simon (CERN) ; Dilly, Joschua Werner (CERN) ; Ferrentino, Vittorio (Universita di Napoli Federico II (IT)) ; Maclean, Ewen Hamish...
LHC injection optics commissioning in 2021 and 2022
Home > Articles & Preprints > CERN Notes > Accelerators & Technology Sector Notes > LHC injection optics commissioning in 2021 and 2022 Report number CERN-ACC-NOTE-2023-0015 Title LHC injection optics commissioning in 2021 and 2022 If you experience any problem watching the video, click the download button below Author(s) Persson, Tobias Hakan Bjorn (CERN) ; Carlier, Felix Simon (CERN) ; Dilly, Joschua Werner (CERN) ; Fartoukh, Stephane (CERN) ; Fol, Elena (CERN) ; Garcia Morales, Hector ;...
Amplitude Detuning from Nonlinear-Corrector- and Triplet-Misalignments at flat-orbit in the LHC and HL-LHC
Home > Articles & Preprints > CERN Notes > Accelerators & Technology Sector Notes > Amplitude Detuning from Nonlinear-Corrector- and Triplet-Misalignments at flat-orbit in the LHC and HL-LHC Report number CERN-ACC-NOTE-2022-0078 Title Amplitude Detuning from Nonlinear-Corrector- and Triplet-Misalignments at flat-orbit in the LHC and HL-LHC If you experience any problem watching the video, click the download button below Download Embed Author(s) Dilly, Joschua Werner (CERN) ; Maclean, Ewen...
Report from LHC MD 3312: Replicating HL-LHC DA
Home > Articles & Preprints > CERN Notes > Accelerators & Technology Sector Notes > Report from LHC MD 3312: Replicating HL-LHC DA Report number CERN-ACC-NOTE-2022-0021 Title Report from LHC MD 3312: Replicating HL-LHC DA If you experience any problem watching the video, click the download button below Download Embed Author(s) Dilly, Joschua Werner (Humboldt University of Berlin (DE)) ; Albert, Markus (CERN) ; Carlier, Felix Simon (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria ;...
Prospects for beam-based study of dodecapole nonlinearities in the CERN High-Luminosity Large Hadron Collider
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Bridging mathematics and physics: models of the evolution of dynamic aperture in hadron colliders and applications to LHC
Title Bridging mathematics and physics: models of the evolution of dynamic aperture in hadron colliders and applications to LHC Author(s) Van der Veken, Frederik (CERN ; Malta U.) ; Bazzani, Armando (U. Bologna, DIFA ; INFN, Bologna) ; Giovannozzi, Massimo (CERN) ; Maclean, Ewen Hamish (CERN ; Malta U.) ; Montanari, Carlo Emiglio (U. Bologna, DIFA) ; Goethem, Wietse Van (CERN ; Antwerp U.) Imprint 7 p.
LHC 3324: Counteracting coupling decay at injection,
Report number CERN-ACC-NOTE-2021-0008 Title LHC 3324: Counteracting coupling decay at injection, Author(s) Persson, Tobias Hakan Bjorn (CERN) ; Maclean, Ewen Hamish (CERN) ; Hulpers, Fredrik ; Solfaroli Camillocci, Matteo (CERN) ; Hofer, Michael (CERN) ; Tomas Garcia, Rogelio (CERN) ; Garcia-Tabares Valdivieso, Ana (Universidad Complutense (ES)) Corporate author(s) CERN. Geneva. ATS Department Imprint 22 02 2021. - 22 p.
Strategy for Landau damping of head-tail instabilities at top energy in the HL-LHC
Report number CERN-ACC-NOTE-2020-0059 Title Strategy for Landau damping of head-tail instabilities at top energy in the HL-LHC Author(s) Buffat, Xavier (CERN) ; Antipov, Sergey ; Arduini, Gianluigi (CERN) ; De Maria, Riccardo (CERN) ; Karastathis, Nikos ; Kostoglou, Sofia (CERN) ; Koval, Adam (University of Dundee (GB)) ; Maclean, Ewen Hamish (CERN) ; Mounet, Nicolas (CERN) ; Papaphilippou, Yannis (CERN) ; Persson, Tobias Hakan Bjorn (CERN) ; Tomas Garcia, Rogelio (CERN) Corporate author(s)...
Combined ramp and telescopic squeeze: MD 3270
Report number CERN-ACC-2020-0028 Title Combined ramp and telescopic squeeze: MD 3270 If you experience any problem watching the video, click the download button below Download Embed Viewed by - users Author(s) Fartoukh, Stephane (CERN) ; Azzopardi, Gabriella (CERN) ; Bruce, Roderik (CERN) ; Buffat, Xavier (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria ; Fuster Martinez, Nuria ; Iadarola, Giovanni (CERN) ; Karastathis, Nikos ; Kostoglou, Sofia (CERN) ; Maclean, Ewen Hamish (CERN)...
MD 3603: Dynamic Aperture with uncorrected dipole b3
Report number CERN-ACC-NOTE-2020-0049 Title MD 3603: Dynamic Aperture with uncorrected dipole b3 If you experience any problem watching the video, click the download button below Download Embed Viewed by - users Author(s) Hofer, Michael (Vienna University of Technology (AT)) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Dilly, Joschua Werner (Humboldt University of Berlin (DE)) ; Fol, Elena (Goethe University Frankfurt (DE)) ; Garcia-Tabares Valdivieso, Ana (Universidad...
MD4944: Local linear coupling measurement at the IPs
Report number CERN-ACC-NOTE-2020-0013 Title MD4944: Local linear coupling measurement at the IPs Download Embed Viewed by 3 users Author(s) Persson, Tobias Hakan Bjorn (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Hofer, Michael (Vienna University of Technology (AT)) ; Maclean, Ewen Hamish (University of Malta (MT)) ; Tomas Garcia, Rogelio (CERN) ; Garcia-Tabares Valdivieso, Ana (Universidad Complutense (ES)) Corporate author(s) CERN. Geneva.
An alternative method to measure amplitude dependence of the closest tune approach
Report number CERN-ACC-NOTE-2020-0007 Title An alternative method to measure amplitude dependence of the closest tune approach Download Embed Viewed by 2 users Author(s) Maclean, Ewen Hamish (University of Malta (MT)) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Persson, Tobias Hakan Bjorn (CERN) ; Tomas Garcia, Rogelio (CERN) ; Fuchsberger, Kajetan Corporate author(s) CERN. Geneva.
Report and Analysis from LHC MD 3311: Amplitude detuning at end-of-squeeze
Report number CERN-ACC-NOTE-2019-0042 Title Report and Analysis from LHC MD 3311: Amplitude detuning at end-of-squeeze Download Embed Viewed by 12 users Author(s) Dilly, Joschua Werner (Humboldt University of Berlin (DE)) ; Albert, Markus (CERN) ; Argyropoulos, Theodoros (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Hofer, Michael (Vienna University of Technology (AT)) ; Malina, Lukas (CERN) ; Maclean, Ewen Hamish (University of Malta (MT)) ; Solfaroli Camillocci, Elena...
First High-Intensity Beam Tests with Telescopic Flat Optics at the LHC
Report number CERN-ACC-2019-0052 Title First High-Intensity Beam Tests with Telescopic Flat Optics at the LHC Download Embed Viewed by 1 users Author(s) Fartoukh, Stephane (CERN) ; Azzopardi, Gabriella (University of Malta (MT)) ; Bruce, Roderik (CERN) ; Buffat, Xavier (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria ; Dilly, Joschua Werner (Ministere des affaires etrangeres et europeennes (FR)) ; Fol, Elena (Johann-Wolfgang-Goethe Univ.
Detailed review of the LHC optics commissioning for the nonlinear era
Report number CERN-ACC-2019-0029 Title Detailed review of the LHC optics commissioning for the nonlinear era Download Embed Viewed by 3 users Author(s) Maclean, Ewen Hamish (University of Malta (MT)) ; Tomas Garcia, Rogelio (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Fol, Elena (Johann-Wolfgang-Goethe Univ.
Round telescopic optics with large telescopic index
This paper highlights the main results from the 2017 LHC MD program which was deployed to commission round ATS optics with high telescopic index, and ultimately to study their properties in terms of long-range beam-beam effect and octupole thresholds for coherent instabilities (MD2269).
Round telescopic optics with large telescopic index
Thjis paper highlights the main results from the 2017 LHC MD program which was deployed to commission round ATS optics with high telescopic index, and ultimately to study their properties in terms of long-range beam-beam effects and octupole thresholds for coherent instabilities (MD2269).
MD 2563: Optics measurement and corrections with half integer tune
Internal Note Report number CERN-ACC-NOTE-2018-0055 Title MD 2563: Optics measurement and corrections with half integer tune Author(s) Wegscheider, Andreas (Hamburg University (DE)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Dilly, Joschua Werner (Ministere des affaires etrangeres et europeennes (FR)) ; Fartoukh, Stephane (CERN) ; Fol, Elena (Johann-Wolfgang-Goethe Univ.
Report from LHC MD 2171: Dynamic aperture at 6.5 TeV
Throughout the LHC’s first and second operational runs, increasing emphasis has been placed on the study of nonlinear single-particle beam dynamics. Of particular interest is the beam dynamics at top-energy, end-of-squeeze, where errors in low-β insertions can create strong nonlinear perturbations of the beams.
Optics measurements and corrections at β∗= 2.5 km
Internal Note Report number CERN-ACC-NOTE-2018-0052 Title Optics measurements and corrections at β∗= 2.5 km Author(s) Garcia-Tabares Valdivieso, Ana (Universidad Complutense (ES)) ; Burkhardt, Helmut (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Fol, Elena (Johann-Wolfgang-Goethe Univ.
MD2148: Flat optics
This note reports on the first attempt to measure and correct optics errors at β∗=60/30 cm and β∗=60/15 cm flat optics. In the absence of the Beam 2 vertical AC dipole, the ADT was used in AC-dipole mode to verify local corrections in IR1. A peak β-beating of 24% remained after global corrections in the horizontal plane of arc 45 of Beam 1. β∗ measurements with K-modulation showed a peak β∗-beating of 16% or larger, as IP1 measurement could not be completed.
Report from LHC MD 1391: First tests of the variation of amplitude detuning with crossing angle as an observable for high-order errors in low-β∗ colliders
Nonlinear errors in experimental insertions can pose a significant challenge to the operability of low-β∗ colliders. When crossing schemes are applied high-order errors, such as decapole and dodecapole multipole components in triplets and separation dipoles, can feed-down to give a normal octupole perturbation. Such fields may contribute to distortion of the assumed tune footprint, influencing lifetime and the Landau damping of instabilities.
Report from LHC MDs 1391 and 1483: Tests of new methods for study of nonlinear errors in the LHC experimental insertions
Nonlinear errors in experimental insertions can pose a significant challenge to the operability of low-β∗ colliders. Previously such errors in the LHC have been studied via their feed-down to tune and coupling under the influence of the nominal crossing angle bumps. This method has proved useful in validating various components of the magnetic model.
Report from LHC MD 2171: Amplitude dependent closest tune approach from normal and skew octupoles
Simulation-based studies predict significant amplitude-dependent closest tune approach can be generated by skew octupole sources in conjunction with their normal octupolar counterparts. This has the potential to significantly influence Landau damping at small β∗, where skew octupole errors in the experimental IRs, together with b4 introduced by the Landau octupoles, is predicted to cause large distortion of the tune footprint.
MD2723 - Amplitude Detuning Studies at 6.5 TeV with Various Configurations of the Crossing Scheme
Particular interst exists to better understand the amplitude detuning through the LHC cycle in order to shed some light on possible sources of instabilities, and better prepair for the ?* squeeze to 25cm in 2018. This note reports on the amplitude etuning measurements taken on the 3rd of December of 2017 during MD2723. Amplitude detuning measurements are presented at ?attop with crossing angles and at end-of-squeeze with and without crossing angles.
MD 2485: Active halo control using narrowband and colored noise excitations
This MD note summarizes the actions carried out during the MD 2485 on Active halo control using narrowband and colored noise excitations. The goal of the MD was to repeat some promising cases already tested in the past and introduce a new excitation type based on applying a colored noise. Although we were able to repeat some cases using a narrowband excitation, due to a problem with the waveform generator, the colored noise excitation could not be accomplished as expected.
Report from LHC MD 2158: IR-nonlinear studies
For the ?rst time the LHC is running for luminosity-production with local corrections for nonlinear errors in the ATLAS and CMS insertions. While a major step forward in LHC optics commissioning strategy (and one which has yielded clear operational bene?ts) considerable challenges remain to be overcome, both in regard to the optimization of LHC optics and in order to ensure successful commissioning of the High-Luminosity LHC.
Aperture measurements with AC dipole
Internal Note Report number CERN-ACC-NOTE-2018-0008 Title Aperture measurements with AC dipole Author(s) Fuster Martinez, Nuria (CERN) ; Maclean, Ewen Hamish (CERN) ; Dilly, Joschua Werner (Ministere des affaires etrangeres et europeennes (FR)) ; Nevay, Laurence James (University of London (GB)) ; Bruce, Roderik (CERN) ; Tomas Garcia, Rogelio (CERN) ; Redaelli, Stefano (CERN) ; Persson, Tobias Hakan Bjorn (CERN) Corporate author(s) CERN. Geneva. ATS Department Imprint 19 Feb 2018. - 13 p.
Optics Measurements and Correction Challenges for the HL-LHC
Preprint Report number CERN-ACC-2017-0088 Title Optics Measurements and Correction Challenges for the HL-LHC Author(s) Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Fol, Elena (University of Applied Sciences (DE)) ; Gamba, Davide (CERN) ; Garcia-Tabares Valdivieso, Ana (Universidad Complutense (ES)) ; Giovannozzi, Massimo (CERN) ; Hofer, Michael (Vienna University of Technology (AT)) ;...
MD1405: Demonstration of forced dynamic aperture measurements at injection
Accurate measurements of dynamic aperture become more important for the LHC as it advances into increasingly nonlinear regimes of operations, as well as for the High Luminosity LHC where machine nonlinearities will have a significantly larger impact. Direct dynamic aperture measurements at top energy in the LHC are challenging, and conventional single kick methods are not viable.
Report from LHC MD 1399: Effect of linear coupling on nonlinear observables in the LHC.
Internal Note Report number CERN-ACC-NOTE-2017-0024 Title Report from LHC MD 1399: Effect of linear coupling on nonlinear observables in the LHC. Author(s) Maclean, Ewen Hamish (CERN) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Giovannozzi, Massimo (CERN) ; Persson, Tobias Hakan Bjorn (CERN) ; Tomas Garcia, Rogelio (CERN) Corporate author(s) CERN. Geneva. ATS Department Imprint 31 Jan 2017. - 11 p.
MD1831: Single Bunch Instabilities with Q" and Non-Linear Corrections
During MD1751, it was observed that both a full single beam and 964 non-colliding bunches in Beam 1 (B1) and Beam 2 (B2) were both stable at the End of Squeeze (EOS) for 0A in the Landau ctupoles. At ß* = 40cm there is also a significant Q" arising from the lattice, as well as uncorrected non-linearities in the IRs. Each of these effects could be capable of fully stabilising the beam.
CERN Document Server
This report presents a summary of the Achromatic Telescopic Squeezing (ATS) scheme related activities which took place in 2016, where a new generation of ATS pre-squeezed and telescopic optics was successfully probed, namely: (i) down to a of 10 cm with pilot bunches, and (ii) with more emphasis at intermediate values of 40 cm or 33 cm where collisions were established with nominal bunches, the triplet aperture was measured and collimation measurements with pre-squeezed or moderately...
Suppression of Amplitude dependent closest tune approach and first tests of the ADT as an AC-dipole (MD 1412)
The amplitude detuning has been observed to decrease significantly as the horizontal and vertical tunes are approaching each other. The measured tune split (Qₓ −Qᵧ) versus amplitude was several times bigger than what can be explained with linear coupling during the non-linear MD in 2012 [1]. This effect is potentially harmful since it might cause a loss of Landau damping, hence giving rise to instabilities.
Coupling Measurements and Corrections for the Combined Ramp and Squeeze
In operation of the LHC the ramp and the squeeze process have been independent beam processes up to now. Making them into a combined process would save time to reach the point where the beams are brought to collision. This would increase the integrated luminosity provided by the LHC. One possible source of problems could be deviation from the ideal optics and in particular the control of the transverse coupling.
Demonstration of coupling correction below the per-mil limit in the LHC
Linear coupling between betatron motion in the transverse planes is one of the key optics parameters for any accelerator. It can substantially affect the nonlinear dynamics, influencing both lifetime and the damping of instabilities, as well as affecting the ability to measure and control the linear optics. A review of published material revealed no account of coupling having been corrected significantly below the per-mil level in any hadron accelerator.
CERN Document Server
Internal Note Report number CERN-ACC-NOTE-2016-0033 Title LHC injection optics measurements at commissioning (2015) Author(s) Garcia-Tabares Valdivieso, Ana (Ministere des affaires etrangeres et europeennes (FR)) ; Carlier, Felix Simon (Technische Universiteit Delft (NL)) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Universitat Politecnica Catalunya (ES)) ; Garcia-Bonilla, Alba-Carolina ; Langner, Andy Sven (CERN) ; Maclean, Ewen Hamish (CERN) ; Malina, Lukas (University of Oslo...
CERN Document Server
In operation of the LHC the ramp and the squeeze process have been independent beam processes up to now. Making them into a combined process would save time to reach the point where the beams are brought to collision. This would increase the integrated luminosity provided by the LHC. One possible source of problems could be deviation from the ideal optics and in particular the control of the transverse coupling.
CERN Document Server
Recent observations in the LHC point to the existence of an amplitude dependent closest tune approach. However this dynamical behavior and its underlying mechanism remain unknown. This effect is highly relevant for the LHC as an unexpectedly closest tune approach varying with amplitude modifies the frequency content of the beam and, hence, the Landau damping.
CERN Document Server
Nonlinear errors in low-¯¤ insertions can have a significant impact upon the beam dynamics. In particular reductions in the LHC dynamic aperture of the order of 3 ¾nominal (105 turns) are expected due to the presence of such errors in IR1 and IR5 at ¯¤ = 0.4m. This represents a slight risk to 40 cm operation in 2016.
CERN Document Server
Internal Note Report number CERN-ACC-NOTE-2016-0013 Title Commissioning of the nonlinear chromaticity at injection for LHC Run II Author(s) Maclean, Ewen Hamish (CERN) ; Tomas Garcia, Rogelio (CERN) ; Carlier, Felix Simon ; Langner, Andy Sven (CERN) ; Malina, Lukas (University of Oslo (NO)) ; Persson, Tobias Hakan Bjorn (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Ministere des affaires etrangeres et europeennes (FR)) ; Skowronski, Piotr Krzysztof (CERN) ; Garcia-Tabares...
CERN Document Server
Internal Note Report number CERN-ACC-NOTE-2015-0035 Title LHC optics commissioning at beta*40 cm and 60 cm Author(s) Langner, Andy Sven (Hamburg University (DE)) ; Carlier, Felix Simon (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria (Ministere des affaires etrangeres et europeennes (FR)) ; Garcia-Tabares Valdivieso, Ana (Ministere des affaires etrangeres et europeennes (FR)) ; Maclean, Ewen Hamish (CERN) ; Malina, Lukas (University of Oslo (NO)) ; Persson, Tobias Hakan Bjorn...
CERN Document Server
Internal Note Report number CERN-ACC-NOTE-2015-0033 Title Towards automatic coupling corrections with DOROS BPMs (MD750) Author(s) Persson, Tobias Hakan Bjorn (CERN) ; Gasior, Marek (CERN) ; Langner, Andy Sven (Hamburg University (DE)) ; Lefevre, Thibaut (CERN) ; Maclean, Ewen Hamish (CERN) ; Malina, Lukas (University of Oslo (NO)) ; Olexa, Jakub (Slovak Technical University (SK)) ; Skowronski, Piotr Krzysztof (CERN) ; Robotka, Tomas (CERN) ; Garcia-Tabares Valdivieso, Ana (Ministere des...
CERN Document Server
The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ.
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