Author: Riddone, G.
Paper Title Page
TUPME054 Experimental Study of the Effect of Beam Loading on RF Breakdown Rate in CLIC High-gradient Accelerating Structures 1691
 
  • F. Tecker, R. Corsini, M. Dayyani Kelisani, S. Döbert, A. Grudiev, O. Kononenko, S. Lebet, J.L. Navarro Quirante, G. Riddone, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
  • A. Solodko
    JINR, Dubna, Moscow Region, Russia
  
  RF break­down is a key issue for the multi-TeV high-lu­mi­nos­ity e+e− Com­pact Lin­ear Col­lider (CLIC). Break­downs in the high-gra­di­ent ac­cel­er­a­tor struc­tures can de­flect the beam and de­crease the de­sired lu­mi­nos­ity. The lim­i­ta­tions of the ac­cel­er­at­ing struc­tures due to break­downs have been stud­ied so far with­out a beam pre­sent in the struc­ture. The pres­ence of the beam mod­i­fies the dis­tri­b­u­tion of the elec­tri­cal and mag­netic field dis­tri­b­u­tions, which de­ter­mine the break­down rate. There­fore an ex­per­i­ment has been de­signed for high power test­ing a CLIC pro­to­type ac­cel­er­at­ing struc­ture with a beam pre­sent in the CLIC Test Fa­cil­ity (CTF3). A spe­cial beam line al­lows ex­tract­ing a beam with nom­i­nal CLIC beam cur­rent and du­ra­tion from the CTF3 linac. The paper de­scribes the beam op­tics de­sign for this ex­per­i­men­tal beam line and the com­mis­sion­ing of the ex­per­i­ment with beam.  
 
WEPFI018 Comparison of High Gradient Performance in Varying Cavity Geometries 2741
 
  • T. Higo, T. Abe, Y. Arakida, Y. Higashi, S. Matsumoto, T. Shidara, T. Takatomi, M. Yamanaka
    KEK, Ibaraki, Japan
  • A. Grudiev, G. Riddone, W. Wuensch
    CERN, Geneva, Switzerland
  
  Four types of CLIC pro­to­type TW ac­cel­er­a­tor struc­tures were high-gra­di­ent tested at Nex­tef, KEK, up to 100 MV/m level and the fifth is under test now. The ramp­ing speed of each pro­cess­ing and the re­sul­tant break­down rate were com­pared among them. From this com­par­i­son, it was found that the ramp­ing speed of the struc­tures with open­ing ports for HOM damp­ing with mag­netic cou­pling be­came slow and the re­sul­tant break­down rate be­came high. It was also found that that with lower sur­face mag­netic field showed faster ramp­ing in pro­cess­ing and lower break­down rate. This in­di­cates the role of the mag­netic field on vac­uum break­downs in cop­per struc­ture at the re­gion of sev­eral tens to 100 MV/m. In this paper, we re­view the pro­cess­ing stage and the high gra­di­ent per­for­mance of these struc­tures try­ing to dis­cuss the rel­e­vant pa­ra­me­ters, sur­face elec­tric field, sur­face mag­netic field and other pa­ra­me­ters such as Sc, “com­plex point­ing vec­tor”, to the per­for­mance dif­fer­ence.  
 
WEPFI055 Experience on Fabrication and Assembly of the First Clic Two-Beam Module Prototype 2815
 
  • D. Gudkov, S. Lebet, G. Riddone, F. Rossi
    CERN, Geneva, Switzerland
  • A. Samoshkin
    JINR, Dubna, Moscow Region, Russia
  
  The CLIC two-beam mod­ule pro­to­types are in­tended to prove the de­sign of all tech­ni­cal sys­tems under the dif­fer­ent op­er­a­tion modes. Two val­i­da­tion pro­grams are cur­rently under way and they fore­see the con­struc­tion of four pro­to­type mod­ules for me­chan­i­cal tests with­out beam and three pro­to­type mod­ules for tests with RF and beam. The pro­gram with­out beam will show the ca­pa­bil­ity of the tech­ni­cal so­lu­tions pro­posed to ful­fil the strin­gent re­quire­ments on ra­dio-fre­quency, sup­port­ing, pre-align­ment, sta­bi­liza­tion, vac­uum and cool­ing sys­tems. The en­gi­neer­ing de­sign was per­formed with the use of CAD/CAE soft­ware. Ded­i­cated mock-ups of RF struc­tures, with all me­chan­i­cal in­ter­faces and cho­sen tech­ni­cal so­lu­tions, are used for the tests and there­fore re­li­able re­sults are ex­pected. The com­po­nents were fab­ri­cated by ap­ply­ing dif­fer­ent tech­nolo­gies for the part man­u­fac­tur­ing and join­ing. The first full-size pro­to­type mod­ule was as­sem­bled in 2012. This paper is fo­cused on the pro­duc­tion process in­clud­ing the com­par­i­son of sev­eral tech­ni­cal so­lu­tions adopted dur­ing the re­al­iza­tion. The de­scrip­tion of the mod­ule as­sem­bly and qual­ity con­trol mea­sure­ments are also re­called.  
 
WEPFI056 Study of the Thermo-Mechanical Behavior of the CLIC Two-Beam Modules 2818
 
  • F. Rossi, R. Mondello, G. Riddone
    CERN, Geneva, Switzerland
  • D. Gudkov, A. Samoshkin
    JINR, Dubna, Moscow Region, Russia
  • I. Kossyvakis
    National Technical University of Athens, Zografou, Greece
  • K. Österberg
    HIP, University of Helsinki, Finland
  
  The final lu­mi­nos­ity tar­get of the Com­pact LIn­ear Col­lider (CLIC) im­poses a mi­cron-level sta­bil­ity of the two-me­ter repet­i­tive two-beam mod­ules con­sti­tut­ing the main linacs. Two-beam pro­to­type mod­ules have been as­sem­bled to ex­ten­sively study their thermo-me­chan­i­cal be­hav­iour under dif­fer­ent op­er­a­tion modes. The power dis­si­pa­tion oc­cur­ring in the mod­ules will be re­pro­duced and the ef­fi­ciency of the cor­re­spond­ing cool­ing sys­tems val­i­dated. At the same time, the real en­vi­ron­men­tal con­di­tions pre­sent in the CLIC tun­nel will be stud­ied. Air con­di­tion­ing and ven­ti­la­tion sys­tems will be in­stalled in the ded­i­cated lab­o­ra­tory. Air tem­per­a­ture will be var­ied from 20 to 40 °C, while air flow rate will be reg­u­lated up to 0.8 m/s. Dur­ing all ex­per­i­men­tal tests, the align­ment of the RF struc­tures will be mon­i­tored to in­ves­ti­gate the in­flu­ence of power dis­si­pa­tion and air tem­per­a­ture on the over­all thermo-me­chan­i­cal be­hav­iour. This test pro­gram will allow for bet­ter un­der­stand­ing the be­hav­iour of CLIC mod­ules and the re­sults will be prop­a­gated back to both nu­mer­i­cal mod­el­ling and en­gi­neer­ing de­sign.