Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses
We present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding light on complex nonlinear effects, these studies are applied...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
American Physical Society
2021-02-01
|
Series: | Physical Review Accelerators and Beams |
Online Access: | http://doi.org/10.1103/PhysRevAccelBeams.24.021001 |
id |
doaj-58b40732ee004b41a03537c3e4af184b |
---|---|
record_format |
Article |
spelling |
doaj-58b40732ee004b41a03537c3e4af184b2021-02-11T15:21:06ZengAmerican Physical SocietyPhysical Review Accelerators and Beams2469-98882021-02-0124202100110.1103/PhysRevAccelBeams.24.021001Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lensesMiriam FittererGiulio StancariAlexander ValishevStefano RedaelliDaniel ValuchWe present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding light on complex nonlinear effects, these studies are applied to the design of hollow electron lenses for active beam halo control. In the High-Luminosity Large Hadron Collider (HL-LHC), a considerable amount of energy will be stored in the beam tails. To control and clean the beam halo, the installation of two hollow electron lenses, one per beam, is being considered. In standard electron-lens operation, a proton bunch sees the same electron current at every revolution. Pulsed electron beam operation (i.e., different currents for different turns) is also considered, because it can widen the range of achievable halo removal rates. For an axially symmetric electron beam, only protons in the halo are excited. If a residual field is present at the location of the beam core, these particles are exposed to time-dependent transverse kicks and to noise. We discuss the numerical simulations and the experiments conducted in 2016 and 2017 at injection energy in the LHC. The excitation patterns were generated by the transverse feedback and damping system, which acted as a flexible source of dipole kicks. Proton beam losses, emittances, and transverse distributions were recorded as a function of excitation patterns and strengths. The resonant excitations induced rich dynamical effects and nontrivial changes of the beam distributions, which, to our knowledge, have not previously been observed and studied in this detail. We conclude with a discussion of the tolerable and achievable residual fields and proposals for further studies.http://doi.org/10.1103/PhysRevAccelBeams.24.021001 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Miriam Fitterer Giulio Stancari Alexander Valishev Stefano Redaelli Daniel Valuch |
spellingShingle |
Miriam Fitterer Giulio Stancari Alexander Valishev Stefano Redaelli Daniel Valuch Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses Physical Review Accelerators and Beams |
author_facet |
Miriam Fitterer Giulio Stancari Alexander Valishev Stefano Redaelli Daniel Valuch |
author_sort |
Miriam Fitterer |
title |
Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses |
title_short |
Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses |
title_full |
Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses |
title_fullStr |
Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses |
title_full_unstemmed |
Resonant and random excitations on the proton beam in the Large Hadron Collider for active halo control with pulsed hollow electron lenses |
title_sort |
resonant and random excitations on the proton beam in the large hadron collider for active halo control with pulsed hollow electron lenses |
publisher |
American Physical Society |
series |
Physical Review Accelerators and Beams |
issn |
2469-9888 |
publishDate |
2021-02-01 |
description |
We present the results of numerical simulations and experimental studies about the effects of resonant and random excitations on proton losses, emittances, and beam distributions in the Large Hadron Collider (LHC). In addition to shedding light on complex nonlinear effects, these studies are applied to the design of hollow electron lenses for active beam halo control. In the High-Luminosity Large Hadron Collider (HL-LHC), a considerable amount of energy will be stored in the beam tails. To control and clean the beam halo, the installation of two hollow electron lenses, one per beam, is being considered. In standard electron-lens operation, a proton bunch sees the same electron current at every revolution. Pulsed electron beam operation (i.e., different currents for different turns) is also considered, because it can widen the range of achievable halo removal rates. For an axially symmetric electron beam, only protons in the halo are excited. If a residual field is present at the location of the beam core, these particles are exposed to time-dependent transverse kicks and to noise. We discuss the numerical simulations and the experiments conducted in 2016 and 2017 at injection energy in the LHC. The excitation patterns were generated by the transverse feedback and damping system, which acted as a flexible source of dipole kicks. Proton beam losses, emittances, and transverse distributions were recorded as a function of excitation patterns and strengths. The resonant excitations induced rich dynamical effects and nontrivial changes of the beam distributions, which, to our knowledge, have not previously been observed and studied in this detail. We conclude with a discussion of the tolerable and achievable residual fields and proposals for further studies. |
url |
http://doi.org/10.1103/PhysRevAccelBeams.24.021001 |
work_keys_str_mv |
AT miriamfitterer resonantandrandomexcitationsontheprotonbeaminthelargehadroncolliderforactivehalocontrolwithpulsedhollowelectronlenses AT giuliostancari resonantandrandomexcitationsontheprotonbeaminthelargehadroncolliderforactivehalocontrolwithpulsedhollowelectronlenses AT alexandervalishev resonantandrandomexcitationsontheprotonbeaminthelargehadroncolliderforactivehalocontrolwithpulsedhollowelectronlenses AT stefanoredaelli resonantandrandomexcitationsontheprotonbeaminthelargehadroncolliderforactivehalocontrolwithpulsedhollowelectronlenses AT danielvaluch resonantandrandomexcitationsontheprotonbeaminthelargehadroncolliderforactivehalocontrolwithpulsedhollowelectronlenses |
_version_ |
1724274188381847552 |