Author: Wegscheider, A.
Paper Title Page
TUC4C2 Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System 183
 
  • B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider
    CERN, Meyrin, Switzerland
  
  Funding: Work supported by the HL-LHC project
With High Lu­mi­nos­ity Large Hadron Col­lider (HL-LHC) beam in­ten­si­ties, there are con­cerns that the beam losses in the dis­per­sion sup­pres­sors around the be­ta­tron clean­ing in­ser­tion might ex­ceed the quench lim­its. Fur­ther­more, to max­i­mize the beam life­time it is im­por­tant to re­duce the im­ped­ance as much as pos­si­ble. The col­li­ma­tors con­sti­tute one of the main sources of im­ped­ance in HL-LHC, given the need to op­er­ate with small col­li­ma­tor gaps. To im­prove this, a new op­tics was de­vel­oped which in­creases the beta func­tion in the col­li­ma­tion area, as well as the sin­gle pass dis­per­sion from the pri­mary col­li­ma­tors to the down­stream shower ab­sorbers. Other pos­si­ble im­prove­ments from orbit bumps, to fur­ther en­hance the lo­cally gen­er­ated dis­per­sion, and from asym­met­ric col­li­ma­tor set­tings were also stud­ied. The new so­lu­tions were par­tially tested with 6.8 TeV beams at the LHC in a ded­i­cated ma­chine ex­per­i­ment in 2022. In this paper, the new per­for­mance is re­viewed and prospects for fu­ture op­er­a­tional de­ploy­ment are dis­cussed. 		 
slides icon Slides TUC4C2 [2.222 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
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THBP14 LHC Optics Measurements from Transverse Damper for the High Intensity Frontier 479
 
  • T. Nissinen, F.S. Carlier, M. Le Garrec, E.H. Maclean, T.H.B. Persson, R. Tomás García, A. Wegscheider
    CERN, Meyrin, Switzerland
  
  Cur­rent and fu­ture ac­cel­er­a­tor pro­jects are push­ing the bright­ness and in­ten­sity fron­tier, cre­at­ing new chal­lenges for turn-by-turn based op­tics mea­sure­ments. Trans­verse os­cil­la­tions are lim­ited in am­pli­tude due to par­ti­cle losses. The LHC Trans­verse Damper (ADT) is ca­pa­ble of gen­er­at­ing low am­pli­tude ac-di­pole like trans­verse co­her­ent beam os­cil­la­tions. While the am­pli­tude of such ex­ci­ta­tions is low, it is com­pen­sated by the ex­ci­ta­tion length of the ADT which, in the­ory, can last for up to 48h. Using the ADT, it is pos­si­ble to use the max­i­mum BPM ac­qui­si­tion length and im­prove the spec­tral res­o­lu­tion. First op­tics mea­sure­ments have been per­formed using the ADT in the LHC in 2023, and the re­sults are pre­sented in this paper. Fur­ther­more, some ob­served lim­i­ta­tions of this method are pre­sented and their im­pact on ADT stud­ies are dis­cussed.  
poster icon Poster THBP14 [2.632 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP14  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 25 October 2023
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THBP20 Optics for Landau Damping with Minimized Octupolar Resonances in the LHC 503
 
  • R. Tomás García, F.S. Carlier, L. Deniau, J. Dilly, J. Keintzel, S. Kostoglou, M. Le Garrec, E.H. Maclean, K. Paraschou, T.H.B. Persson, F. Soubelet, A. Wegscheider
    CERN, Meyrin, Switzerland
  
  Op­er­a­tion of the Large Hadron Col­lider (LHC) re­quires strong oc­tupo­lar mag­netic fields to sup­press co­her­ent beam in­sta­bil­i­ties. The am­pli­tude de­tun­ing that is gen­er­ated by these oc­tupo­lar mag­netic fields brings the tune of in­di­vid­ual par­ti­cles close to harm­ful res­o­nances, which are mostly dri­ven by the oc­tupo­lar fields them­selves. In 2023, new op­tics were de­ployed in the LHC at in­jec­tion with op­ti­mized be­ta­tronic phase ad­vances to min­i­mize the res­o­nances from the oc­tupo­lar fields with­out af­fect­ing the am­pli­tude de­tun­ing. This paper re­ports on the op­tics de­sign, com­mis­sion­ing and the life­time mea­sure­ments per­formed to val­i­date the op­tics.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP20  
About • Received ※ 01 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 23 October 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)