Author: Bartosik, H.
Paper Title Page
MOPFI060 Beam Transfer to LHC with the Low Gamma-transition SPS Optics 419
 
  • G. Vanbavinckhove, W. Bartmann, H. Bartosik, C. Bracco, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, V. Mertens, Y. Papaphilippou, J.A. Uythoven, J. Wenninger
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
  
  A new low gamma-tran­si­tion op­tics with a lower in­te­ger tune, was in­tro­duced in the SPS to im­prove beam sta­bil­ity at high in­ten­sity. For trans­fer­ring the beam to the LHC, the ex­trac­tion bumps, ex­trac­tion kick­ers and trans­fer lines needed to be adapted to the new op­tics. In par­tic­u­lar, the trans­fer lines were re-matched and re-com­mis­sioned with the new op­tics. The first op­er­a­tional re­sults are dis­cussed for the SPS ex­trac­tion, the trans­fer lines and the LHC in­jec­tion. A de­tailed com­par­i­son is pre­sented be­tween the old and the new op­tics of the tra­jec­to­ries, dis­per­sion, losses and other per­for­mance as­pects.  
 
MOPWO033 Analysis of LHC Transfer Line Trajectory Drifts 960
 
  • L.N. Drøsdal, W. Bartmann, H. Bartosik, C. Bracco, B. Goddard, V. Kain, Y. Papaphilippou, J.A. Uythoven, G. Vanbavinckhove, J. Wenninger
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
  
  The LHC is filled from the SPS via two 3km long trans­fer lines. In the first years of LHC op­er­a­tion large tra­jec­tory vari­a­tions were dis­cov­ered. The sources of bunch-by-bunch and shot-by-shot tra­jec­tory vari­a­tions had been iden­ti­fied and im­proved by the 2012 LHC run. The ori­gins of the longer term drifts were how­ever still un­clear and sig­nif­i­cant time was spent cor­rect­ing the tra­jec­to­ries. In the last part of the 2012 run the op­tics in the SPS was changed to lower tran­si­tion en­ergy. Tra­jec­tory sta­bil­ity and cor­rec­tion fre­quency will be com­pared be­tween be­fore and after the op­tics change in the SPS. The sources of the vari­a­tions have now been iden­ti­fied and will be dis­cussed in this paper. Reme­dies for op­er­a­tion after the long shut­down will be pro­posed.  
 
TUPFI002 Electron Cloud and Scrubbing Studies for the LHC 1331
 
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  • G. Arduini, V. Baglin, H. Bartosik, C.O. Domínguez, J.F. Esteban Müller, G. Iadarola, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, F. Zimmermann
    CERN, Geneva, Switzerland
  • C.O. Domínguez
    EPFL, Lausanne, Switzerland
  • G.H.I. Maury Cuna
    CINVESTAV, Mexico City, Mexico
  
  Elec­tron cloud build-up re­sult­ing from beam-in­duced mul­ti­pact­ing is one of the major lim­i­ta­tions for the op­er­a­tion of the LHC with beams with close bunch spac­ing. Elec­tron clouds in­duce un­wanted pres­sure rise, heat loads on the beam screens of the su­per­con­duct­ing mag­nets and beam in­sta­bil­i­ties. Op­er­a­tion with bunch spac­ing of 50 ns in 2011 and 2012 has re­quired de­creas­ing the Sec­ondary Elec­tron Yield of the beam screens below the mul­ti­pact­ing thresh­old for beams with this bunch spac­ing. This was achieved by con­tin­u­ous elec­tron bom­bard­ment in­duced by op­er­at­ing the ma­chine with high in­ten­sity beams with 50 and 25 ns spac­ing dur­ing ded­i­cated pe­ri­ods at in­jec­tion en­ergy (450 GeV) and at top en­ergy (3.5 and 4 TeV). The evo­lu­tion of the Sec­ondary Elec­tron Yield dur­ing these pe­ri­ods, at dif­fer­ent sec­tions of the ma­chine, can be es­ti­mated by pres­sure, heat load and by bunch-by-bunch RF sta­ble phase mea­sure­ments. The ex­per­i­men­tal in­for­ma­tion on the scrub­bing process will be dis­cussed and a pos­si­ble “scrub­bing strat­egy” to allow the op­er­a­tion with 50ns and 25ns beams after the Long Shut­down in 2013-2014 will be pre­sented.  
 
TUPME034 Experimental Studies for Future LHC Beams in the SPS 1652
 
  • H. Bartosik, T. Argyropoulos, T. Bohl, S. Cettour-Cave, J.F. Esteban Müller, W. Höfle, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko
    CERN, Geneva, Switzerland
  • A.Y. Molodozhentsev
    KEK, Ibaraki, Japan
  
  The High Lu­mi­nos­ity LHC (HL-LHC) pro­ject re­quires sig­nif­i­cantly higher beam in­ten­sity than presently ac­ces­si­ble in the LHC in­jec­tor chain. The aim of the LHC in­jec­tors up­grade pro­ject (LIU) is to pre­pare the CERN ac­cel­er­a­tors for the fu­ture needs of the LHC. There­fore a se­ries of ma­chine stud­ies with high bright­ness beams were per­formed, as­sess­ing the pre­sent per­for­mance reach and iden­ti­fy­ing re­main­ing lim­i­ta­tions. Of par­tic­u­lar con­cern are beam load­ing and lon­gi­tu­di­nal in­sta­bil­i­ties at high en­ergy, space charge for beams with 50ns bunch spac­ing and elec­tron cloud ef­fects for beams with 25ns bunch spac­ing. This paper pro­vides a sum­mary of the per­formed stud­ies, that have been pos­si­ble thanks to the im­ple­men­ta­tion of the SPS low gamma-tran­si­tion op­tics.  
 
TUPME046 Performance of SPS Low Transition Energy Optics for LHC Ion Beams 1667
 
  • F. Antoniou, G. Arduini, H. Bartosik, T. Bohl, S. Cettour Cave, K. Cornelis, D. Manglunki, Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  An op­tics with low tran­si­tion en­ergy has been de­vel­oped in the SPS for re­mov­ing in­ten­sity lim­i­ta­tions of the LHC pro­ton beam and has be­come op­er­a­tional to­wards the sec­ond part of the 2012 LHC pro­ton run. This op­tics was also used for fill­ing the LHC with lead ions dur­ing the p/Pb run of the be­gin­ning of 2013. The im­pact of this op­tics in the per­for­mance of the LHC ion beam is stud­ied here, es­pe­cially with re­spect to col­lec­tive ef­fects, at the SPS in­jec­tion en­ergy. In par­tic­u­lar, the po­ten­tial gain of the in­creased beam sizes pro­vided by this op­tics, with re­spect to losses and emit­tance blow up due to space-charge and In­tra­beam Scat­ter­ing (IBS) is eval­u­ated. The mea­sured life­time is com­pared with the one pro­vided by the Tou­schek ef­fect and its in­ter­play with RF noise is stud­ied. The mod­els are sup­ported by mea­sure­ments in the SPS and in the LHC flat bot­tom.  
 
TUPWA049 Short High-Intensity Bunches for Plasma Wakefield Experiment AWAKE in the CERN SPS 1820
 
  • H. Timko, T. Argyropoulos, H. Bartosik, T. Bohl, J.F. Esteban Müller, E.N. Shaposhnikova
    CERN, Geneva, Switzerland
  • A.V. Petrenko
    BINP SB RAS, Novosibirsk, Russia
  
  Ob­tain­ing the short­est pos­si­ble bunch length in com­bi­na­tion with the small­est trans­verse emit­tances and high­est bunch in­ten­sity – this is the wish list of the pro­ton-bunch dri­ven, plasma wake­field ac­cel­er­a­tion ex­per­i­ment AWAKE cur­rently under fea­si­bil­ity study at CERN. A few mea­sure­ment ses­sions were con­ducted to de­ter­mine the achiev­able bunch prop­er­ties and their re­pro­ducibil­ity. To ob­tain a short bunch length, the bunches were ro­tated in lon­gi­tu­di­nal phase space using the max­i­mum avail­able RF volt­age prior to ex­trac­tion. Mea­sure­ments were car­ried out in two op­tics with dif­fer­ent tran­si­tion en­er­gies. The main per­for­mance lim­i­ta­tion is lon­gi­tu­di­nal beam in­sta­bil­ity that de­vel­ops dur­ing the ac­cel­er­a­tion ramp. With lower tran­si­tion en­ergy, beam sta­bil­ity is im­proved, but the bucket area is smaller for the same volt­age. Based on the re­sults ob­tained, we shall dis­cuss the choice of op­tics, the im­pact of lon­gi­tu­di­nal in­sta­bil­i­ties, the im­por­tance of re­pro­ducibil­ity, as well as op­tions for im­prov­ing the bunch pa­ra­me­ters.  
 
WEXB101 Optics Optimization for Reducing Collective Effects and Raising Instability Thresholds in Lepton and Hadron Rings 2033
 
  • Y. Papaphilippou, F. Antoniou, H. Bartosik
    CERN, Geneva, Switzerland
  
  This paper cov­ers re­cent progress in the de­sign of op­tics so­lu­tions to min­i­mize col­lec­tive ef­fects such as beam in­sta­bil­i­ties, in­tra-beam scat­ter­ing or space charge in hadron and lep­ton rings. The nec­es­sary steps are re­viewed for de­sign­ing the op­tics of high-in­ten­sity and high-bright­ness syn­chro­trons but also ul­tra-low emit­tance lep­ton stor­age rings, whose per­for­mance is strongly dom­i­nated by col­lec­tive ef­fects. Par­tic­u­lar em­pha­sis is given to pro­posed and ex­ist­ing de­signs il­lus­trated by sim­u­la­tions and beam mea­sure­ments.  
slides icon Slides WEXB101 [24.511 MB]  
 
WEPEA014 Recent Electron Cloud Studies in the SPS 2525
 
  • G. Iadarola, H. Bartosik, M. Driss Mensi, H. Neupert, G. Rumolo, M. Taborelli
    CERN, Geneva, Switzerland
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  
  It is im­por­tant to qual­ify the pre­sent sta­tus of the SPS with re­spect to the elec­tron cloud be­fore the Long Shut­down of the CERN ac­cel­er­a­tor com­plex, which will take place in 2013-2014. There­fore sev­eral elec­tron cloud stud­ies were per­formed dur­ing the 2012 run in order to get a full char­ac­ter­i­za­tion of the be­hav­ior of the SPS with the LHC-type beams with 25 ns bunch spac­ing, which can be very sen­si­tive to elec­tron cloud ef­fects. The col­lected in­for­ma­tion should allow to un­der­stand up to which ex­tent this long pe­riod with­out beam op­er­a­tion - and the re­lated in­ter­ven­tions on the ma­chine - will de­grade the pre­sent con­di­tion­ing state of the SPS, which has been achieved by “scrub­bing” over sev­eral years. Sev­eral mea­sure­ments with dif­fer­ent beam con­di­tions have been col­lected also on the elec­tron cloud de­tec­tors in­stalled in the ma­chine. These re­sults, in com­bi­na­tion with de­tailed sim­u­la­tion stud­ies, will pro­vide the basis for defin­ing strate­gies of elec­tron cloud mit­i­ga­tion as re­quired for the pro­duc­tion of fu­ture high in­ten­sity and high bright­ness beams within the LHC In­jec­tors Up­grade (LIU) pro­ject.  
 
WEPEA053 Progress with the Upgrade of the SPS for the HL-LHC Era 2624
 
  • B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J.F. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, Ö. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
  
  The de­mand­ing beam per­for­mance re­quire­ments of the HL-LHC pro­ject trans­late into a set of re­quire­ments and up­grade paths for the LHC in­jec­tor com­plex. In this paper the per­for­mance re­quire­ments for the SPS and the known lim­i­ta­tions are re­viewed in the light of the 2012 op­er­a­tional ex­pe­ri­ence. The var­i­ous SPS up­grades in progress and still under con­sid­er­a­tion are de­scribed, in ad­di­tion to the ma­chine stud­ies and sim­u­la­tions per­formed in 2012. The ex­pected ma­chine per­for­mance reach is es­ti­mated on the basis of the pre­sent knowl­edge, and the re­main­ing de­ci­sions that still need to be made con­cern­ing up­grade op­tions are de­tailed.  
 
WEPEA056 Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation 2633
 
  • C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed
    CERN, Geneva, Switzerland
  
  The pro­posed Multi-Turn Ex­trac­tion (MTE) for the CERN PS al­lows to re­duce the over­all ex­trac­tion losses for high in­ten­sity beams. The re­quired lon­gi­tu­di­nal struc­ture of the pro­ton beam in­duces un­avoid­able beam losses at the mag­netic ex­trac­tion sep­tum. The in­stal­la­tion of a dummy sep­tum with an ap­pro­pri­ate shield­ing has been pro­posed to lo­calise losses and to shadow the mag­netic sep­tum. Such a de­vice, lo­cated in the ex­trac­tion re­gion, im­poses tight con­straints on the avail­able beam aper­ture. Mod­i­fied ex­trac­tion schemes have been pro­posed and in this paper they will be pre­sented and dis­cussed in de­tail to­gether with the mea­sured per­for­mance.  
 
WEPEA060 Plans for the Upgrade of CERN's Heavy Ion Complex 2645
 
  • D. Manglunki, M. E. Angoletta, H. Bartosik, A. Blas, D. Bodart, M.A. Bodendorfer, T. Bohl, J. Borburgh, E. Carlier, J.-M. Cravero, H. Damerau, L. Ducimetière, A. Findlay, R. Garoby, S.S. Gilardoni, B. Goddard, S. Hancock, E.B. Holzer, J.M. Jowett, T. Kramer, D. Kuchler, A.M. Lombardi, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille
    CERN, Geneva, Switzerland
  
  To reach a lu­mi­nos­ity higher than 6×1027 Hz/cm2 for Pb-Pb col­li­sions, as ex­pected by the ALICE ex­per­i­ment after its up­grade dur­ing the 2nd Long LHC Shut­down (LS2), sev­eral up­grades will have to be per­formed in the CERN ac­cel­er­a­tor com­plex, from the source to the LHC it­self. This paper first de­tails the pre­sent lim­i­ta­tions and then de­scribes the strat­egy for the dif­fer­ent ma­chines in the ion in­jec­tor chain. Both fill­ing schemes and pos­si­ble hard­ware up­grades are dis­cussed.  
 
WEPEA061 The First LHC p-Pb run: Performance of the Heavy Ion Production Complex 2648
 
  • D. Manglunki, M. E. Angoletta, H. Bartosik, G. Bellodi, A. Blas, M.A. Bodendorfer, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, M. O'Neil, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger
    CERN, Geneva, Switzerland
  
  TThe first LHC pro­ton-ion run took place in Jan­u­ary-Feb­ru­ary 2013; it was the first ex­ten­sion to the col­lider pro­gramme, as this mode was not in­cluded in the de­sign re­port. This paper pre­sents the per­for­mance of the heavy ion and pro­ton pro­duc­tion com­plex, and de­tails the is­sues en­coun­tered, in par­tic­u­lar the cre­ation of the same bunch pat­tern in both beams.  
 
WEPME060 First Results and Analysis of the Performance of a 4 GS/s Intra-bunch Vertical Feedback System at the SPS 3070
 
  • J.M. Cesaratto, J.E. Dusatko, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut
    SLAC, Menlo Park, California, USA
  • H. Bartosik, W. Höfle, G. Kotzian, U. Wehrle
    CERN, Geneva, Switzerland
  
  Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
We pre­sent ex­per­i­men­tal mea­sure­ments taken from SPS ma­chine de­vel­op­ment stud­ies with an in­tra-bunch feed­back chan­nel. These stud­ies use a dig­i­tal sig­nal pro­cess­ing sys­tem to im­ple­ment gen­eral-pur­pose con­trol al­go­rithms on mul­ti­ple sam­ples across a sin­gle SPS bunch ( for ease of syn­chro­niza­tion with the SPS RF fre­quency a sam­pling fre­quency of 3.2 GS/sec. is im­ple­mented). These ini­tial stud­ies con­cen­trate on sin­gle-bunch mo­tion, and study the ver­ti­cal be­ta­tron mo­tion as the feed­back con­trol is var­ied. The stud­ies are fo­cused on val­i­dat­ing sim­u­la­tion mod­els of the beam dy­nam­ics with feed­back. Time and fre­quency do­main re­sults in­clude ex­ci­ta­tion and damp­ing of in­tra-bunch mo­tion with pos­i­tive and neg­a­tive feed­back. We pre­sent an overview of the chal­lenges of in­tra-bunch feed­back, and high­light meth­ods to time-align the pickup and kicker sig­nals within the closed-loop feed­back chan­nel. 		 
 
THOBB102 Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines 3106
 
  • N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef
    CERN, Geneva, Switzerland
  • M. Migliorati, L. Palumbo
    URLS, Rome, Italy
  
  The beam cou­pling im­ped­ance could lead to lim­i­ta­tions in beam bright­ness and qual­ity, and there­fore it needs ac­cu­rate quan­tifi­ca­tion and con­tin­u­ous mon­i­tor­ing in order to de­tect and mit­i­gate high im­ped­ance sources. In the CERN ma­chines, for ex­am­ple, kick­ers and col­li­ma­tors are ex­pected to be the main con­trib­u­tors to the total imag­i­nary part of the trans­verse im­ped­ance. In order to de­tect the other sources, a beam based mea­sure­ment was de­vel­oped: from the vari­a­tion of be­ta­tron phase beat­ing with in­ten­sity, it is pos­si­ble to de­tect the lo­ca­tions of main im­ped­ance sources. In this work we pre­sent the ap­pli­ca­tion of the method with beam mea­sure­ments in the CERN PS, SPS and LHC.  
slides icon Slides THOBB102 [7.224 MB]  
 
THPWO080 Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics 3945
 
  • Y. Papaphilippou, G. Arduini, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, C. Bracco, S. Cettour-Cave, K. Cornelis, L.N. Drøsdal, J.F. Esteban Müller, B. Goddard, A. Guerrero, W. Höfle, V. Kain, G. Rumolo, B. Salvant, E.N. Shaposhnikova, H. Timko, D. Valuch, G. Vanbavinckhove, J. Wenninger
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
  
  An op­tics in the SPS with lower in­te­ger tunes (20 ver­sus 26) was pro­posed and in­tro­duced in ma­chine stud­ies since 2010, as a mea­sure for in­creas­ing trans­verse and lon­gi­tu­di­nal in­sta­bil­ity thresh­olds, es­pe­cially at low en­ergy, for the LHC pro­ton beams. After two years of ma­chine stud­ies and care­ful op­ti­mi­sa­tion, the new “Q20” op­tics be­came op­er­a­tional in Sep­tem­ber 2012 and steadily de­liv­ered beam to the LHC until the end of the run. This paper re­views the op­er­a­tional per­for­mance of the Q20 op­tics with re­spect to trans­verse and lon­gi­tu­di­nal beam char­ac­ter­is­tics in the SPS, en­abling high bright­ness beams in­jected into the LHC. As­pects of lon­gi­tu­di­nal beam sta­bil­ity, trans­mis­sion, high-en­ergy orbit con­trol and beam trans­fer are dis­cussed.