Author: Baudrenghien, P.
Paper Title Page
TUO1AB02 Upgrades of the RF Systems in the LHC Injector Complex 165
 
  • H. Damerau, M.E. Angoletta, T. Argyropoulos, P. Baudrenghien, A. Blas, T. Bohl, A.C. Butterworth, A. Findlay, R. Garoby, S.S. Gilardoni, S. Hancock, W. Höfle, J.C. Molendijk, E. Montesinos, M.M. Paoluzzi, D. Perrelet, C. Rossi, E.N. Shaposhnikova
    CERN, Geneva, Switzerland
  
  In the frame­work of the LHC In­jec­tor Up­grade (LIU) pro­ject the ra­dio-fre­quency (RF) sys­tems of the syn­chro­trons in the LHC in­jec­tor chain will un­dergo sig­nif­i­cant im­prove­ments to reach the high beam in­ten­sity and qual­ity re­quired by the High-Lu­mi­nos­ity (HL) LHC. Fol­low­ing the re­cent up­grade of the lon­gi­tu­di­nal beam con­trol sys­tem in the PS Booster (PSB), tests with Finemet cav­i­ties are being per­formed in view of a com­plete re­place­ment of the ex­ist­ing RF sys­tems in the PSB by ones based on this tech­nol­ogy. In the PS a sim­i­lar wide-band Finemet cav­ity has been in­stalled as a lon­gi­tu­di­nal damper. New 1-turn delay feed­backs on the main ac­cel­er­at­ing cav­i­ties to re­duce their im­ped­ance have also been com­mis­sioned. Ad­di­tional feed­back and beam con­trol im­prove­ments are fore­seen. A major up­grade of the main RF sys­tem in the SPS by re­group­ing sec­tions of its trav­el­ling wave cav­i­ties, in­creas­ing the num­ber of cav­i­ties from four to six, will re­duce beam-load­ing and allow higher in­ten­si­ties to be ac­cel­er­ated. The up­grade in­cludes the in­stal­la­tion of two new RF power plants and new feed­back sys­tems. All up­grades will be eval­u­ated with re­spect to their ex­pected ben­e­fits for the beams to the LHC.  
slides icon Slides TUO1AB02 [4.317 MB]  
 
THO4LR03 Studies on Controlled RF Noise for the LHC 414
 
  • H. Timko, P. Baudrenghien, E.N. Shaposhnikova
    CERN, Geneva, Switzerland
  • T. Mastoridis
    CalPoly, San Luis Obispo, California, USA
  
  RF phase noise is pur­posely in­jected into the LHC 400 MHz RF sys­tem dur­ing the ac­cel­er­a­tion ramp for con­trolled lon­gi­tu­di­nal emit­tance blow-up, in order to main­tain lon­gi­tu­di­nal beam sta­bil­ity. Al­though the op­er­a­tional blow-up works re­li­ably, stud­ies of the in­jected RF noise are de­sir­able not only to allow for a bet­ter-con­trolled, more flex­i­ble blow-up, but also for other ap­pli­ca­tions such as the mit­i­ga­tion of ma­chine-com­po­nent heat­ing through ap­pro­pri­ate bunch shap­ing. Con­cern­ing the noise in­jec­tion, an al­ter­na­tive al­go­rithm was de­vel­oped and im­ple­mented in the hard­ware, but first tests re­vealed un­ex­pected mod­u­la­tion of the achieved bunch length along the ring, and sub­se­quently, the­o­ret­i­cal stud­ies have been launched. In this paper, we pre­sent a sum­mary of on­go­ing mea­sure­ment analy­sis and sim­u­la­tion stud­ies that shall ex­plain pre­vi­ous ob­ser­va­tions, pre­dict what can be ex­pected in dif­fer­ent cases, and thus help to op­ti­mise the RF noise in gen­eral.  
slides icon Slides THO4LR03 [1.440 MB]