Pub Date : 2020-04-15DOI: 10.1103/PHYSREVACCELBEAMS.23.090704
Nanshun Huang, H. Deng
X-ray free electron laser oscillators (XFELO) is future light source to produce fully coherent hard X-ray pulses. The X-rays circulate in an optical cavity built from multiple Bragg reflecting mirrors, which has a high reflectance in a bandwidth of ten meV level. The X-ray crystal mirrors exposed to intense X-ray beams in the cavity are subjects to thermal deformations that shift and distort the Bragg reflection. Therefore, the stability of the XFELO operation relies on the abilities of mirrors to preserve the Bragg reflection under such heat load. A new approach was used to analyze the heat load of mirrors and the XFELO operation. The essential light-matter interaction is simulated by the GEANT4 with a dedicated Bragg-reflection physical process to obtain the precise absorption information of the XFELO pulse in the crystals. The transient thermal conduction is analyzed by the finite-element analysis software upon the energy absorption information extract from GEANT4 simulation. A simplified heat-load model is then developed to integrate the heat load in the XFELO. With the help of the heat-load model, the analysis of XFELO operating with several cryogenically cooled diamond mirrors is conducted. The results indicate that the heat load would induce an oscillation when XFELO operates without enough cooling.
{"title":"Thermal loading on crystals in an x-ray free-electron laser oscillator","authors":"Nanshun Huang, H. Deng","doi":"10.1103/PHYSREVACCELBEAMS.23.090704","DOIUrl":"https://doi.org/10.1103/PHYSREVACCELBEAMS.23.090704","url":null,"abstract":"X-ray free electron laser oscillators (XFELO) is future light source to produce fully coherent hard X-ray pulses. The X-rays circulate in an optical cavity built from multiple Bragg reflecting mirrors, which has a high reflectance in a bandwidth of ten meV level. The X-ray crystal mirrors exposed to intense X-ray beams in the cavity are subjects to thermal deformations that shift and distort the Bragg reflection. Therefore, the stability of the XFELO operation relies on the abilities of mirrors to preserve the Bragg reflection under such heat load. A new approach was used to analyze the heat load of mirrors and the XFELO operation. The essential light-matter interaction is simulated by the GEANT4 with a dedicated Bragg-reflection physical process to obtain the precise absorption information of the XFELO pulse in the crystals. The transient thermal conduction is analyzed by the finite-element analysis software upon the energy absorption information extract from GEANT4 simulation. A simplified heat-load model is then developed to integrate the heat load in the XFELO. With the help of the heat-load model, the analysis of XFELO operating with several cryogenically cooled diamond mirrors is conducted. The results indicate that the heat load would induce an oscillation when XFELO operates without enough cooling.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86466562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-13DOI: 10.1103/PhysRevAccelBeams.22.054501; 10.1103/PhysRevAccelBeams.23.039901
V. Tikhomirov
The coherent process of particle deflection by aligned atomic strings and planes of oriented crystals is accompanied by incoherent scattering by atomic cores. While the coherent particle deflection, described by the axial or planar averaged potential, becomes more and more classical at high energies, the incoherent scattering of relativistic particles remains essentially quantum. Though the latter reminds the scattering by atoms of amorphous medium at high enough momentum transfers, at the smallest ones the incoherent scattering process in crystals experiences some modification by the influence of the inhomogeneity of the atom distribution in the plane, normal to the crystal axis or plane. Considering the axial case as a more general example, we present a consistent theory of high energy particles incoherent scattering in oriented crystals. The latter takes into consideration both the quantum scattering nature and the atom distribution inhomogeneity, revealing the limited applicability of the scattering cross section notion. The way to incorporate the quantum scattering features into the widely used classical trajectory simulations is elaborated using newly introduced mean square scattering angle definition.
{"title":"Relativistic particle incoherent scattering in oriented crystals","authors":"V. Tikhomirov","doi":"10.1103/PhysRevAccelBeams.22.054501; 10.1103/PhysRevAccelBeams.23.039901","DOIUrl":"https://doi.org/10.1103/PhysRevAccelBeams.22.054501; 10.1103/PhysRevAccelBeams.23.039901","url":null,"abstract":"The coherent process of particle deflection by aligned atomic strings and planes of oriented crystals is accompanied by incoherent scattering by atomic cores. While the coherent particle deflection, described by the axial or planar averaged potential, becomes more and more classical at high energies, the incoherent scattering of relativistic particles remains essentially quantum. Though the latter reminds the scattering by atoms of amorphous medium at high enough momentum transfers, at the smallest ones the incoherent scattering process in crystals experiences some modification by the influence of the inhomogeneity of the atom distribution in the plane, normal to the crystal axis or plane. Considering the axial case as a more general example, we present a consistent theory of high energy particles incoherent scattering in oriented crystals. The latter takes into consideration both the quantum scattering nature and the atom distribution inhomogeneity, revealing the limited applicability of the scattering cross section notion. The way to incorporate the quantum scattering features into the widely used classical trajectory simulations is elaborated using newly introduced mean square scattering angle definition.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88861385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The results of numerical simulation of the channeling of ultra-relativistic 270 MeV electrons and positrons in a diamond crystal are presented. Using the MBN Explorer package, the trajectories of the have been determined of the particles incident on a 20 microns thick crystal along (110) crystallographic plane. The channeling parameters and radiation spectra of electrons and positrons have been computed for the cases of straight and periodically bent diamond crystals.
{"title":"Channeling of ultrarelativistic particles in a diamond crystal","authors":"K. B. Agapiev, V. Ivanov, A. Korol, A. Solov'yov","doi":"10.18721/JPM.11213","DOIUrl":"https://doi.org/10.18721/JPM.11213","url":null,"abstract":"The results of numerical simulation of the channeling of ultra-relativistic 270 MeV electrons and positrons in a diamond crystal are presented. Using the MBN Explorer package, the trajectories of the have been determined of the particles incident on a 20 microns thick crystal along (110) crystallographic plane. The channeling parameters and radiation spectra of electrons and positrons have been computed for the cases of straight and periodically bent diamond crystals.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80624910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Scheinker, Simon Hirlaender, F. Velotti, S. Gessner, G. D. Della Porta, V. Kain, B. Goddard, R. Ramjiawan
Multi-objective optimization is important for particle accelerators where various competing objectives must be satisfied routinely such as, for example, transverse emittance vs bunch length. We develop and demonstrate an online multi-time scale multi-objective optimization algorithm that performs real time feedback on particle accelerators. We demonstrate the ability to simultaneously minimize the emittance and maintain a reference trajectory of a beam in the electron beamline in CERN's Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE).
{"title":"Online multi-objective particle accelerator optimization of the AWAKE electron beam line for simultaneous emittance and orbit control","authors":"A. Scheinker, Simon Hirlaender, F. Velotti, S. Gessner, G. D. Della Porta, V. Kain, B. Goddard, R. Ramjiawan","doi":"10.1063/5.0003423","DOIUrl":"https://doi.org/10.1063/5.0003423","url":null,"abstract":"Multi-objective optimization is important for particle accelerators where various competing objectives must be satisfied routinely such as, for example, transverse emittance vs bunch length. We develop and demonstrate an online multi-time scale multi-objective optimization algorithm that performs real time feedback on particle accelerators. We demonstrate the ability to simultaneously minimize the emittance and maintain a reference trajectory of a beam in the electron beamline in CERN's Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE).","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75228000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-22DOI: 10.23732/CYRCP-2020-009.362
D. Quartullo, M. Migliorati, M. Zobov
The CERN FCC-ee top-up booster synchrotron will accelerate electrons and positrons from an injection energy of 20 GeV up to an extraction energy between 45.6 GeV and 182.5 GeV depending on the operation mode. These accelerated beams will be used for the initial filling of the high-luminosity FCC-ee collider and for keeping the beam current constant over time using continuous top-up injection. Due to the high-intensities of the circulating beams, collective effects may represent a limitation in the top-up booster. In this work we present a first evaluation of the impedance model and the effects on beam dynamics. Methods to mitigate possible instabilities will be also discussed.
{"title":"Study of collective effects in the CERN FCC-ee top-up booster","authors":"D. Quartullo, M. Migliorati, M. Zobov","doi":"10.23732/CYRCP-2020-009.362","DOIUrl":"https://doi.org/10.23732/CYRCP-2020-009.362","url":null,"abstract":"The CERN FCC-ee top-up booster synchrotron will accelerate electrons and positrons from an injection energy of 20 GeV up to an extraction energy between 45.6 GeV and 182.5 GeV depending on the operation mode. These accelerated beams will be used for the initial filling of the high-luminosity FCC-ee collider and for keeping the beam current constant over time using continuous top-up injection. Due to the high-intensities of the circulating beams, collective effects may represent a limitation in the top-up booster. In this work we present a first evaluation of the impedance model and the effects on beam dynamics. Methods to mitigate possible instabilities will be also discussed.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89409492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-20DOI: 10.1103/REVMODPHYS.93.015006
V. Shiltsev, F. Zimmermann
Since the initial development of charged particle colliders in the middle of the 20th century, these advanced scientific instruments have been at the forefront of scientific discoveries in high energy physics. Collider accelerator technology and beam physics have progressed immensely and modern facilities now operate at energies and luminosities many orders of magnitude greater than the pioneering colliders of the early 1960s. In addition, the field of colliders remains extremely dynamic and continues to develop many innovative approaches. Indeed, several novel concepts are currently being considered for designing and constructing even more powerful future colliders. In this paper, we first review the colliding beam method and the history of colliders, and then present the major achievements of operational machines and the key features of near-term collider projects that are currently under development. We conclude with an analysis of numerous proposals and studies for far-future colliders. The evaluation of their respective potentials reveals tantalizing prospects for further significant breakthroughs in the collider field.
{"title":"Modern and future colliders","authors":"V. Shiltsev, F. Zimmermann","doi":"10.1103/REVMODPHYS.93.015006","DOIUrl":"https://doi.org/10.1103/REVMODPHYS.93.015006","url":null,"abstract":"Since the initial development of charged particle colliders in the middle of the 20th century, these advanced scientific instruments have been at the forefront of scientific discoveries in high energy physics. Collider accelerator technology and beam physics have progressed immensely and modern facilities now operate at energies and luminosities many orders of magnitude greater than the pioneering colliders of the early 1960s. In addition, the field of colliders remains extremely dynamic and continues to develop many innovative approaches. Indeed, several novel concepts are currently being considered for designing and constructing even more powerful future colliders. In this paper, we first review the colliding beam method and the history of colliders, and then present the major achievements of operational machines and the key features of near-term collider projects that are currently under development. We conclude with an analysis of numerous proposals and studies for far-future colliders. The evaluation of their respective potentials reveals tantalizing prospects for further significant breakthroughs in the collider field.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91436950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-19DOI: 10.1103/PhysRevAccelBeams.24.051302
Pratik Manwani, N. Majernik, J. Rosenzweig
Using a periodic electron beam bunch train to resonantly excite plasma wakefields in the quasi-nonlinear (QNL) regime has distinct advantages over employing a single, higher charge bunch. Resonant excitation in the QNL regime can produce plasma electron blowout using very low emittance beams with a small charge per pulse: the local density perturbation is extremely nonlinear, achieving total rarefaction, yet the resonant response of the plasma electrons at the plasma frequency is preserved. Such a pulse train, with inter-bunch spacing equal to the plasma period, can be produced via inverse free-electron laser bunching. To achieve resonance with a laser wavelength of a few microns, a high plasma density is used, with the attendant possibility of obtaining extremely large wakefield amplitude, near 1 TV/m for FACET-II parameters. In this article, we use particle-in-cell simulations to study the plasma response, the beam modulation evolution, and the instabilities encountered, that arise when using a bunching scheme to resonantly excite waves in a dense plasma.
{"title":"Resonant excitation of very high gradient plasma wakefield accelerators by optical-period bunch trains","authors":"Pratik Manwani, N. Majernik, J. Rosenzweig","doi":"10.1103/PhysRevAccelBeams.24.051302","DOIUrl":"https://doi.org/10.1103/PhysRevAccelBeams.24.051302","url":null,"abstract":"Using a periodic electron beam bunch train to resonantly excite plasma wakefields in the quasi-nonlinear (QNL) regime has distinct advantages over employing a single, higher charge bunch. Resonant excitation in the QNL regime can produce plasma electron blowout using very low emittance beams with a small charge per pulse: the local density perturbation is extremely nonlinear, achieving total rarefaction, yet the resonant response of the plasma electrons at the plasma frequency is preserved. Such a pulse train, with inter-bunch spacing equal to the plasma period, can be produced via inverse free-electron laser bunching. To achieve resonance with a laser wavelength of a few microns, a high plasma density is used, with the attendant possibility of obtaining extremely large wakefield amplitude, near 1 TV/m for FACET-II parameters. In this article, we use particle-in-cell simulations to study the plasma response, the beam modulation evolution, and the instabilities encountered, that arise when using a bunching scheme to resonantly excite waves in a dense plasma.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75967444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Muon $gtextrm{-}2$ Experiment (E989) at Fermilab has a goal of measuring the muon anomaly ($a_mu$) with unprecedented precision using positive muons. This measurement is motivated by the difference between the previous Brookhaven $a_mu$ measurement and Standard Model prediction exceeding three standard deviations, which hints at the possibility of physics beyond the Standard Model. Muons are circulated in a storage ring, and the measurement requires a precise determination of the muon anomalous precession frequency (spin precession relative to momentum) from the resulting decay positron time and energy measurements collected with calorimeters. The average magnetic field seen by the muons needs to be known with high precision, and so the storage ring magnetic field is shimmed to be very uniform and is continually monitored with nuclear magnetic resonance (NMR) probes. Detailed Muon Campus beamline and muon storage ring simulations are also required for quantifying beam dynamics and spin-related systematic effects in the determination of the muon anomalous precession frequency, e.g. muon losses during the measurement window. At the time of the conference, the experiment has recently commenced Run-3, and the release of Run-1 physics results is planned for 2020.
{"title":"Toward the Frontiers of Particle Physics with the Muon g-2 Experiment","authors":"E. Valetov","doi":"10.2172/1623356","DOIUrl":"https://doi.org/10.2172/1623356","url":null,"abstract":"The Muon $gtextrm{-}2$ Experiment (E989) at Fermilab has a goal of measuring the muon anomaly ($a_mu$) with unprecedented precision using positive muons. This measurement is motivated by the difference between the previous Brookhaven $a_mu$ measurement and Standard Model prediction exceeding three standard deviations, which hints at the possibility of physics beyond the Standard Model. Muons are circulated in a storage ring, and the measurement requires a precise determination of the muon anomalous precession frequency (spin precession relative to momentum) from the resulting decay positron time and energy measurements collected with calorimeters. The average magnetic field seen by the muons needs to be known with high precision, and so the storage ring magnetic field is shimmed to be very uniform and is continually monitored with nuclear magnetic resonance (NMR) probes. Detailed Muon Campus beamline and muon storage ring simulations are also required for quantifying beam dynamics and spin-related systematic effects in the determination of the muon anomalous precession frequency, e.g. muon losses during the measurement window. At the time of the conference, the experiment has recently commenced Run-3, and the release of Run-1 physics results is planned for 2020.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87780886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.1103/PHYSREVACCELBEAMS.24.034002
S. Kostoglou, G. Arduini, Y. Papaphilippou, G. Sterbini, L. Intelisano
Harmonics of the mains frequency (50 Hz) have been systematically observed in the transverse beam spectrum of the Large Hadron Collider (LHC) since the start of its operation in the form of dipolar excitations. In the presence of strong non-linearities such as beam-beam interactions, as many of these power supply ripple tones reside in the vicinity of the betatron tune they can increase the tune diffusion of the particles in the distribution, leading to proton losses and eventually to a significant reduction of the beam lifetime. The aim of this paper is to determine whether the 50~Hz harmonics have an impact on the beam performance of the LHC. A quantitative characterization of the ripple spectrum present in the operation of the accelerator, together with an understanding of its source is an essential ingredient to also evaluate the impact of the 50~Hz harmonics on the future upgrade of the LHC, the High Luminosity LHC (HL-LHC). To this end, simulations with the single-particle tracking code, SixTrack, are employed including a realistic ripple spectrum as extracted from experimental observations to quantify the impact of such effects in terms of tune diffusion, Dynamic Aperture and beam lifetime. The methods and results of the tracking studies are reported and discussed in this paper.
{"title":"Impact of the 50 Hz harmonics on the beam evolution of the Large Hadron Collider","authors":"S. Kostoglou, G. Arduini, Y. Papaphilippou, G. Sterbini, L. Intelisano","doi":"10.1103/PHYSREVACCELBEAMS.24.034002","DOIUrl":"https://doi.org/10.1103/PHYSREVACCELBEAMS.24.034002","url":null,"abstract":"Harmonics of the mains frequency (50 Hz) have been systematically observed in the transverse beam spectrum of the Large Hadron Collider (LHC) since the start of its operation in the form of dipolar excitations. In the presence of strong non-linearities such as beam-beam interactions, as many of these power supply ripple tones reside in the vicinity of the betatron tune they can increase the tune diffusion of the particles in the distribution, leading to proton losses and eventually to a significant reduction of the beam lifetime. The aim of this paper is to determine whether the 50~Hz harmonics have an impact on the beam performance of the LHC. A quantitative characterization of the ripple spectrum present in the operation of the accelerator, together with an understanding of its source is an essential ingredient to also evaluate the impact of the 50~Hz harmonics on the future upgrade of the LHC, the High Luminosity LHC (HL-LHC). To this end, simulations with the single-particle tracking code, SixTrack, are employed including a realistic ripple spectrum as extracted from experimental observations to quantify the impact of such effects in terms of tune diffusion, Dynamic Aperture and beam lifetime. The methods and results of the tracking studies are reported and discussed in this paper.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86471540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.1103/PHYSREVACCELBEAMS.24.034001
S. Kostoglou, G. Arduini, Y. Papaphilippou, G. Sterbini, L. Intelisano
Since the beginning of the Large Hadron Collider (LHC) commissioning, spectral components at harmonics of the mains frequency (50 Hz) have been observed in the transverse beam spectrum. This paper presents an overview of the most important observations, collected during the latest physics operation of the LHC in 2018, which clearly indicates that the harmonics are the result of a real beam excitation rather than an instrumental feature. Based on these findings, potential sources of the perturbation are discussed and a correlation with power supply ripple originating from the magnets' power supplies is presented.
{"title":"Origin of the 50 Hz harmonics in the transverse beam spectrum of the Large Hadron Collider","authors":"S. Kostoglou, G. Arduini, Y. Papaphilippou, G. Sterbini, L. Intelisano","doi":"10.1103/PHYSREVACCELBEAMS.24.034001","DOIUrl":"https://doi.org/10.1103/PHYSREVACCELBEAMS.24.034001","url":null,"abstract":"Since the beginning of the Large Hadron Collider (LHC) commissioning, spectral components at harmonics of the mains frequency (50 Hz) have been observed in the transverse beam spectrum. This paper presents an overview of the most important observations, collected during the latest physics operation of the LHC in 2018, which clearly indicates that the harmonics are the result of a real beam excitation rather than an instrumental feature. Based on these findings, potential sources of the perturbation are discussed and a correlation with power supply ripple originating from the magnets' power supplies is presented.","PeriodicalId":8436,"journal":{"name":"arXiv: Accelerator Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73230150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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