Author: Zimmermann, F.
Paper Title Page
MOPAB032 Estimates of Collective Effects for the FCC-e+e− Pre-Booster Ring 148
 
  • O. Etisken, F. Antoniou, K. Oide, Y. Papaphilippou, F. Zimmermann
    CERN, Geneva, Switzerland
  • A.K. Çiftçi
    Izmir University of Economics, Balçova/Izmir, Turkey
  
  The FCC-e+e− in­jec­tor com­plex needs to pro­duce and to trans­port high-in­ten­sity e+ and e- beams at a fast rep­e­ti­tion rate for top­ping up the col­lider at its col­li­sion en­ergy. Two dif­fer­ent op­tions are under con­sid­er­a­tion as pre-ac­cel­er­a­tor be­fore the bunches are trans­ferred to the high-en­ergy booster: ei­ther using the ex­ist­ing SPS ma­chine or de­sign­ing a com­pletely new ring. The pur­pose of this paper is to pre­sent the stud­ies of col­lec­tive ef­fects with an­a­lyt­i­cal es­ti­mates for both the pre-booster ring de­sign op­tions in­clud­ing space charge (SC), lon­gi­tu­di­nal mi­cro-wave in­sta­bil­ity (LMI), trans­verse mode cou­pling in­sta­bil­ity (TMCI), ion ef­fects, elec­tron cloud (e-cloud), co­her­ent syn­chro­tron ra­di­a­tion (CSR), and in­tra-beam scat­ter­ing (IBS).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB032  
About • paper received ※ 17 May 2021       paper accepted ※ 27 May 2021       issue date ※ 15 August 2021  
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MOPAB168 Nanoplasmonic Accelerators Towards Tens of TeraVolts per Meter Gradients Using Nanomaterials 574
 
  • A.A. Sahai, M. Golkowski, V. Harid
    CU Denver, Denver, Colorado, USA
  • C. Joshi
    UCLA, Los Angeles, California, USA
  • T.C. Katsouleas
    Duke ECE, Durham, North Carolina, USA
  • A. Latina, F. Zimmermann
    CERN, Geneva, Switzerland
  • J. Resta-López
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • P. Taborek
    UCI, Irvine, California, USA
  • A.G.R. Thomas
    University of Michigan, Ann Arbor, Michigan, USA
  
  Funding: University of Colorado Denver
Ul­tra-high gra­di­ents which are crit­i­cal for fu­ture ad­vances in high-en­ergy physics, have so far re­lied on plasma and di­elec­tric ac­cel­er­at­ing struc­tures. While bulk crys­tals were pre­dicted to offer un­par­al­leled TV/m gra­di­ents that are at least two or­ders of mag­ni­tude higher than gaseous plas­mas, crys­tal-based ac­cel­er­a­tion has not been re­al­ized in prac­tice. We have de­vel­oped the con­cept of nanoplas­monic crunch-in sur­face modes which uti­lizes the tun­abil­ity of col­lec­tive os­cil­la­tions in nano­ma­te­ri­als to open up un­prece­dented tens of TV/m gra­di­ents. Par­ti­cle beams in­ter­act­ing with nano­ma­te­ri­als that have vac­uum-like core re­gions, ex­pe­ri­ence min­i­mal dis­rup­tive ef­fects such as fil­a­men­ta­tion and col­li­sions, while the beam-dri­ven crunch-in modes sus­tain tens of TV/m gra­di­ents. More­over, as the ef­fec­tive aper­tures for trans­verse and lon­gi­tu­di­nal crunch-in wakes are dif­fer­ent, the lim­i­ta­tion of tra­di­tional scal­ing of struc­ture wake­fields to smaller di­men­sions is sig­nif­i­cantly re­laxed. The SLAC FACET-II ex­per­i­ment of the nano2WA col­lab­o­ra­tion will uti­lize ul­tra-short, high-cur­rent elec­tron beams to ex­cite non­lin­ear plas­monic modes and demon­strate this pos­si­bil­ity.
* doi:10.1109/ACCESS.2021.3070798
** doi:10.1142/S0217751X19430097
*** indico.fnal.gov/event/19478/contributions/52561
**** indico.cern.ch/event/867535/contributions/3716404 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB168  
About • paper received ※ 11 May 2021       paper accepted ※ 08 June 2021       issue date ※ 20 August 2021  
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TUPAB005 Emittance Estimates for the Future Circular Collider 1338
 
  • L. van Riesen-Haupt, T.K. Charles, R. Tomás García, F. Zimmermann
    CERN, Meyrin, Switzerland
  • T.K. Charles
    The University of Liverpool, Liverpool, United Kingdom
  
  The align­ment strat­egy of the FCC-ee has a large im­pact on its lu­mi­nos­ity. Larger align­ment tol­er­ances re­sult in in­creased cou­pling and a sub­se­quently higher ver­ti­cal emit­tance. At the same time, tighter align­ment tol­er­ances around the 100 km ring are a major cost dri­ver. This paper ap­plies an­a­lyt­i­cal emit­tance es­ti­mate meth­ods to the FCC-ee and com­pares their pre­dic­tions to data from sim­u­la­tions with dif­fer­ent align­ment tol­er­ances. These meth­ods can be used to help un­der­stand the im­pact of mis­align­ments of cer­tain mag­net groups and to come up with an ef­fi­cient align­ment strat­egy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB005  
About • paper received ※ 16 May 2021       paper accepted ※ 14 June 2021       issue date ※ 26 August 2021  
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TUPAB010 Impact of Bunch Current on Optics Measurements in SuperKEKB 1356
 
  • J. Keintzel, R. Tomás García, F. Zimmermann
    CERN, Geneva, Switzerland
  • T. Ishibashi, H. Koiso, G. Mitsuka, A. Morita, K. Ohmi, Y. Ohnishi, H. Sugimoto, S. Terui, M. Tobiyama, R.J. Yang, D. Zhou
    KEK, Ibaraki, Japan
  
  Su­perKEKB has re­cently achieved the world record in­stan­ta­neous lu­mi­nos­ity of 2.8 × 1034 \si{cm-2s-1} and aims at reach­ing a tar­get lu­mi­nos­ity of about 6 × 1035 \si{cm-2s-1}. To ac­com­plish this goal it is planned to in­crease beam cur­rents up to §I{3.6}{A} and §I{2.6}{A} for the positron and the elec­tron ring, re­spec­tively. In­creas­ing the beam cur­rents and, in par­tic­u­lar, the num­ber of lep­tons per bunch, can im­pact the op­tics pa­ra­me­ters ob­tained by turn-by-turn mea­sure­ments, such as the be­ta­tron tune or phase ad­vance. Op­tics mea­sure­ments per­formed at var­i­ous bunch cur­rents can give first in­di­ca­tions of pos­si­ble in­ten­sity de­pen­dent ef­fects. In this paper, the ef­fect of vary­ing bunch cur­rent on op­tics mea­sure­ments at Su­perKEKB is ex­plored.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB010  
About • paper received ※ 18 May 2021       paper accepted ※ 10 June 2021       issue date ※ 30 August 2021  
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TUPAB027 Review of Accelerator Limitations and Routes to Ultimate Beams 1397
 
  • F. Zimmermann
    CERN, Geneva, Switzerland
  • R.W. Aßmann
    DESY, Hamburg, Germany
  • M. Bai, G. Franchetti
    GSI, Darmstadt, Germany
  
  Funding: This work was supported in part by the European Commission under the HORIZON 2020 project I.FAST, no. 101004730.
Var­i­ous phys­i­cal and tech­nol­ogy-de­pen­dent lim­its are en­coun­tered for key per­for­mance pa­ra­me­ters of ac­cel­er­a­tors such as high-gra­di­ent ac­cel­er­a­tion, high-field bend­ing, beam size, beam bright­ness, beam in­ten­sity and lu­mi­nos­ity. This paper will re­view these lim­its and the as­so­ci­ated chal­lenges. Pos­si­ble fig­ures-of-merit and path­ways to ul­ti­mate col­lid­ers will also be ex­plored. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB027  
About • paper received ※ 16 May 2021       paper accepted ※ 02 August 2021       issue date ※ 23 August 2021  
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WEPAB011 Update on the Low Emittance Tuning of the e+/e- Future Circular Collider 2601
 
  • T.K. Charles
    The University of Liverpool, Liverpool, United Kingdom
  • B.J. Holzer, F. Zimmermann
    CERN, Meyrin, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
  
  The FCC-ee pro­ject stud­ies the de­sign of a fu­ture 100 km e+/e cir­cu­lar col­lider for pre­ci­sion stud­ies and rare decay ob­ser­va­tions in the range of 90 to 350 GeV cen­ter of mass en­ergy with lu­mi­nosi­ties in the order of 1035 cm-2 s−1. To achieve ul­tra-low ver­ti­cal emit­tance a highly ef­fec­tive emit­tance tun­ing scheme is re­quired. In this paper, we de­scribe a com­pre­hen­sive cor­rec­tion strat­egy used for the low emit­tance tun­ing. The strat­egy in­cludes Dis­per­sion Free Steer­ing, lin­ear cou­pling com­pen­sa­tion based on Res­o­nant Dri­ving Terms and beta beat cor­rec­tion util­is­ing re­sponse ma­tri­ces.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB011  
About • paper received ※ 18 May 2021       paper accepted ※ 23 June 2021       issue date ※ 02 September 2021  
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WEPAB029 Challenges for the Interaction Region Design of the Future Circular Collider FCC-ee 2668
 
  • M. Boscolo, A. Ciarma, F. Fransesini, L. Pellegrino
    INFN/LNF, Frascati, Italy
  • N. Bacchetta
    INFN- Sez. di Padova, Padova, Italy
  • M. Benedikt, H. Burkhardt, M.A. Jones, R. Kersevan, M. Lueckhof, E. Montbarbon, K. Oide, L. Watrelot, F. Zimmermann
    CERN, Meyrin, Switzerland
  • L. Brunetti, M. Serluca
    IN2P3-LAPP, Annecy-le-Vieux, France
  • M. Dam
    NBI, København, Denmark
  • M. Koratzinos
    MIT, Cambridge, Massachusetts, USA
  • M. Migliorati
    INFN-Roma1, Rome, Italy
  • A. Novokhatski, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • F. Poirier
    CNRS - DR17, RENNES, France
  
  Funding: This work was partially supported by the EC HORIZON 2020 project FCC-IS, grant agreement n.951754, and by the U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-76SF-00515.
The FCC-ee is a pro­posed fu­ture high-en­ergy, high-in­ten­sity and high pre­ci­sion lep­ton col­lider. Here, we pre­sent the lat­est de­vel­op­ments for the FCC-ee in­ter­ac­tion re­gions, which shall en­sure op­ti­mum con­di­tions for the par­ti­cle physics ex­per­i­ments. We dis­cuss mea­sures of back­ground re­duc­tion and a re­vised in­ter­ac­tion re­gion lay­out in­clud­ing a low im­ped­ance com­pact beam cham­ber de­sign. We also dis­cuss the pos­si­ble im­pact of the ra­di­a­tion gen­er­ated in the in­ter­ac­tion re­gion in­clud­ing beam­strahlung. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB029  
About • paper received ※ 11 May 2021       paper accepted ※ 23 June 2021       issue date ※ 30 August 2021  
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WEPAB225 Transverse and Longitudinal Single Bunch Instabilities in FCC-ee 3153
 
  • E. Carideo, D. Quartullo, F. Zimmermann
    CERN, Meyrin, Switzerland
  • D. De Arcangelis
    Sapienza University of Rome, Rome, Italy
  • M. Migliorati, M. Zobov
    INFN/LNF, Frascati, Italy
  
  Im­prov­ing the ac­cu­racy of the im­ped­ance model of an ac­cel­er­a­tor is im­por­tant for keep­ing beam in­sta­bil­i­ties and power loss under con­trol. Here, by means of the Py­HEAD- TAIL track­ing code, we first re­view the lon­gi­tu­di­nal mi- crowave in­sta­bil­ity thresh­old for FCC-ee by tak­ing into ac- count the lon­gi­tu­di­nal im­ped­ance model eval­u­ated so far. More­over, we pre­sent the re­sults of beam dy­nam­ics sim­ula- tions, in­clud­ing both the lon­gi­tu­di­nal and trans­verse wake- fields due to the re­sis­tive wall, in order to eval­u­ate the in­flu- ence of the bunch length on the trans­verse mode cou­pling in­sta­bil­ity. The re­sults of the trans­verse beam dy­nam­ics are also com­pared with the Vlasov solver DEL­PHI.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB225  
About • paper received ※ 10 May 2021       paper accepted ※ 01 July 2021       issue date ※ 18 August 2021  
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THPAB233 Could "Flakes" of Neutral Paramagnetic or Dipolar Molecules Explain Beam Losses in the LHC? 4254
 
  • G. Franchetti
    GSI, Darmstadt, Germany
  • F. Zimmermann
    CERN, Meyrin, Switzerland
  
  "Flakes" of neu­tral water or oxy­gen mol­e­cules car­ry­ing an elec­tric or mag­netic di­pole mo­ment can be at­tracted and trapped by the elec­tro­mag­netic field of the cir­cu­lat­ing LHC pro­ton beam. The pos­si­ble pres­ence of such flakes in the vac­uum sys­tem could ex­plain beam losses and beam in­sta­bil­i­ties en­coun­tered dur­ing the 2017 and 2018 LHC runs, and the ob­served ef­fect of an ex­ter­nal mag­netic field.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB233  
About • paper received ※ 09 May 2021       paper accepted ※ 12 July 2021       issue date ※ 02 September 2021  
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