Author: Kostoglou, S.
Paper Title Page
THA1C1 High Intensity Beam Dynamics Challenges for HL-LHC 344
 
  • N. Mounet, H. Bartosik, P. Baudrenghien, R. Bruce, X. Buffat, R. Calaga, R. De Maria, C.N. Droin, L. Giacomel, M. Giovannozzi, G. Iadarola, S. Kostoglou, B. Lindström, L. Mether, E. Métral, Y. Papaphilippou, K. Paraschou, S. Redaelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás García
    CERN, Meyrin, Switzerland
 
  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. Here we pre­sent the as­so­ci­ated con­straints and the pro­posed mit­i­ga­tion mea­sures to achieve the base­line per­for­mance of the up­graded LHC ma­chine. We also dis­cuss the in­ter­play of these mit­i­ga­tion mea­sures with other as­pects of the ac­cel­er­a­tor, such as the phys­i­cal and dy­namic aper­ture, ma­chine pro­tec­tion, mag­net im­per­fec­tions, op­tics, and the col­li­ma­tion sys­tem.  
slides icon Slides THA1C1 [3.385 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1C1  
About • Received ※ 01 October 2023 — Revised ※ 10 October 2023 — Accepted ※ 12 October 2023 — Issued ※ 15 October 2023
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THBP15 Optimizing Resonance Driving Terms Using MAD-NG Parametric Maps 483
 
  • L. Deniau, S. Kostoglou, E.H. Maclean, K. Paraschou, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
 
  In 2023, a re­view of the LHC oc­tupo­lar res­o­nance dri­ving terms at in­jec­tion was car­ried out, mo­ti­vated by two ob­ser­va­tions: (i) un­wanted losses dur­ing the in­jec­tion process with strongly pow­ered oc­tupoles and (ii) an ex­pected re­duc­tion in emit­tance growth from e-cloud ef­fects in sim­u­la­tions with weaker oc­tupo­lar res­o­nances. The MAD-NG code was used to si­mul­ta­ne­ously op­ti­mise the main oc­tupo­lar res­o­nances: 4Qx, 4Qy, and 2Qx-2Qy by ad­just­ing 16 quadru­pole fam­i­lies and 16 oc­tu­pole fam­i­lies, for a total of 32 pa­ra­me­ters. These knobs were in­tro­duced as pa­ra­me­ters in the trans­fer map, al­low­ing the Ja­co­bian re­quired by the op­ti­miser to be cal­cu­lated in a sin­gle pass, sav­ing 32 ad­di­tional op­tics eval­u­a­tions and avoid­ing fi­nite dif­fer­ence ap­prox­i­ma­tions. Con­straints on tunes, am­pli­tude de­tun­ing and op­tics around the ma­chine were also con­sid­ered as part of the op­ti­mi­sa­tion process. This paper re­views the para­met­ric op­ti­mi­sa­tion with MAD-NG and com­pares the re­sults with MADX-PTC.  
poster icon Poster THBP15 [0.938 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP15  
About • Received ※ 02 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 17 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
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THBP21 Increasing High Luminosity LHC Dynamic Aperture Using Optics Optimizations 507
 
  • R. De Maria, Y. Angelis, C.N. Droin, S. Kostoglou, F. Plassard, G. Sterbini, R. Tomás García
    CERN, Meyrin, Switzerland
 
  Funding: Work supported by the HL-LHC project.
CERN’s Large Hadron Col­lider (LHC) is ex­pected to op­er­ate with un­prece­dented beam cur­rent and bright­ness from the be­gin­ning of Run 4 in 2029. In the con­text of the High Lu­mi­nos­ity LHC pro­ject, the base­line op­er­a­tional sce­nar­ios are cur­rently being de­vel­oped. They re­quire a large oc­tu­pole cur­rent and a large chro­matic­ity through­out the en­tire cycle, which dri­ves a strong re­duc­tion of dy­namic aper­ture, in par­tic­u­lar at in­jec­tion and dur­ing the lu­mi­nos­ity pro­duc­tion phase. De­spite being highly con­strained, the LHC op­tics and sex­tu­pole and oc­tu­pole cor­rec­tor cir­cuits still offer a few de­grees of free­dom that can be used to re­duce res­o­nances and the ex­tent of the tune foot­print at con­stant Lan­dau damp­ing, thereby lead­ing to an im­prove­ment of the dy­namic aper­ture. This con­tri­bu­tion pre­sents the sta­tus of the analy­sis that will be used to pre­pare the op­tics base­line for LHC Run 4.
 
poster icon Poster THBP21 [1.286 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP21  
About • Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 31 October 2023
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