• H. Shaker
  IPM, Tehran
• R. Corsini, H. Shaker, P.K. Skowronski, I. Syratchev, F. Tecker
  CERN, Geneva

The pulse com­pres­sor is lo­cat­ed after the klystron to in­crease the power peak by stor­ing the en­er­gy at the be­gin­ning and re­leas­ing it near the end of klystron out­put pulse. In the CTF3 [1] pulse com­pres­sors a dou­bling of the peak power is achieved ac­cord­ing to our needs and the ma­chine pa­ram­e­ters. The mag­ni­tude of peak power, pulse length and flat­ness can be con­trolled by using a phase mod­u­la­tor for the input sig­nal of klystrons. A C++ code is writ­ten to sim­u­late the pulse com­pres­sor be­haviour ac­cord­ing to the klystron out­put pulse power. By man­u­al­ly chang­ing the re­lat­ed pa­ram­e­ters in the code for the best match, the qual­i­ty fac­tor and the fill­ing time of pulse com­pres­sor cav­i­ties can be de­ter­mined. This code also cal­cu­lates and sends the suit­able phase to the phase mod­u­la­tor ac­cord­ing to the klystron out­put pulse power and the de­sired pulse length and peak power.

• F. Marcellini, D. Alesini, A. Ghigo
  INFN/LNF, Frascati (Roma)
• A. Andersson, I. Syratchev
  CERN, Geneva

In the two beam ac­cel­er­a­tion scheme the Main Beam must be pre­cise­ly syn­chro­nized with re­spect to the RF power pro­duced by the Drive Beam. Tim­ing er­rors would have an im­pact on the col­lid­er per­for­mances. The Drive Beam phase er­rors should be con­trolled, by means of a feed for­ward sys­tem, with­in 0.1° (23fs @ 12GHz) to avoid a lu­mi­nos­i­ty re­duc­tion larg­er than 2%. A beam phase ar­rival mon­i­tor is an es­sen­tial com­po­nent of the sys­tem. Its de­sign has been based on the fol­low­ing main re­quire­ments: res­o­lu­tion of the order of 20fs, very low cou­pling impedance due to the very high beam cur­rent and in­te­grat­ed fil­ter­ing el­e­ments to re­ject RF noise and weak fields in the beam pipe that could oth­er­wise af­fect the mea­sure­ments.

• I. Syratchev, A. Cappelletti
  CERN, Geneva

One cru­cial de­vel­op­ment for CLIC is an ad­justable high-pow­er rf de­vice which con­trols the out­put power level of in­di­vid­u­al Power Ex­trac­tion and Trans­fer Struc­tures (PETS) even while fed with a con­stant drive beam cur­rent. The CLIC two-beam rf sys­tem is de­signed to have a low, ap­prox­i­mate­ly 10^-7, break­down rate dur­ing nor­mal op­er­a­tion and break­downs will occur in both ac­cel­er­at­ing struc­tures and the PETS them­selves. In order to re­cov­er from the break­downs and reestab­lish sta­ble op­er­a­tion, it is nec­es­sary to have the ca­pa­bil­i­ty to switch off a sin­gle PETS/ac­cel­er­at­ing struc­ture unit and then grad­u­al­ly ramp gen­er­at­ed power up again. The base­line strat­e­gy and im­ple­men­ta­tion of such a vari­able high-pow­er mech­a­nism is de­scribed.

• E. Adli
  University of Oslo, Oslo
• A.E. Dabrowski, S. Döbert, M. Olvegård, D. Schulte, I. Syratchev
  CERN, Geneva
• R.L. Lillestol
  NTNU, Trondheim

The CLIC Test Fa­cil­i­ty 3 Test Beam Line is the first pro­to­type for the CLIC drive beam de­cel­er­a­tor. Sta­ble trans­port of the drive beam under de­cel­er­a­tion is a manda­to­ry com­po­nent in the CLIC two-beam scheme. In the Test Beam Line more than 50% of the total en­er­gy will be ex­tract­ed from a 150 MeV, 28 A elec­tron drive beam, by the use of 16 Power Ex­trac­tion and Trans­fer struc­tures. A num­ber of ex­per­i­ments are fore­seen to in­ves­ti­gate the drive beam char­ac­ter­is­tics under de­cel­er­a­tion in the Test Beam Line, in­clud­ing beam sta­bil­i­ty, beam blow up and the ef­fi­cien­cy of the power ex­trac­tion. Gen­er­al bench­mark­ing of de­cel­er­a­tor sim­u­la­tion and the­o­ry stud­ies will also be per­formed. Spe­cial­ly de­signed in­stru­men­ta­tion in­clud­ing pre­ci­sion BPMs, loss mon­i­tors and a time-re­solved spec­trom­e­ter dump will be used for the ex­per­i­ments. This paper de­scribes the ex­per­i­men­tal pro­gram fore­seen for the Test Beam Line, in­clud­ing the rel­e­vance of the re­sults for the CLIC de­cel­er­a­tor stud­ies.

• D. Schulte, R. Corsini, B. Dalena, J.-P. Delahaye, S. Döbert, G. Geschonke, A. Grudiev, J.B. Jeanneret, E. Jensen, P. Lebrun, Y. Papaphilippou, L. Rinolfi, G. Rumolo, H. Schmickler, F. Stulle, I. Syratchev, R. Tomás, W. Wuensch
  CERN, Geneva
• E. Adli
  University of Oslo, Oslo

The physics ex­per­i­ments at CLIC will re­quire that the ma­chine scans lower than nom­i­nal cen­tre-of-mass en­er­gy. We pre­sent dif­fer­ent op­tions to achieve this and dis­cuss the im­pli­ca­tions for lu­mi­nos­i­ty and the ma­chine de­sign.

• F. Toral, P. Abramian, J. Calero, D. Carrillo, F.M. De Aragon, L. García-Tabarés, J.L. Gutiérrez, A. Lara, E. Rodríguez García, L. Sanchez
  CIEMAT, Madrid
• S. Döbert, I. Syratchev
  CERN, Geneva

The goal of the pre­sent CLIC test fa­cil­i­ty (CTF3) is to demon­strate the tech­ni­cal fea­si­bil­i­ty of the CLIC scheme. The Test Beam Line (TBL) is used to study a CLIC de­cel­er­a­tor fo­cus­ing on 12 GHz power pro­duc­tion and the sta­bil­i­ty of the de­cel­er­at­ed beam. The ex­tract­ed CTF3 drive beam from the com­bin­er ring (CR) fea­tures a max­i­mum in­ten­si­ty of 28 A and 140 ns pulse du­ra­tion, where the Test Beam Line con­sists of 16 cells, each one in­clud­ing a BPM, a quadrupole on top of a mi­crom­e­ter-ac­cu­ra­cy mover and a RF power ex­trac­tor so-called PETS (Power Ex­trac­tion and Trans­fer Struc­ture). This paper de­scribes the first pro­to­type fab­ri­ca­tion tech­niques, with par­tic­u­lar at­ten­tion to the pro­duc­tion of the long cop­per rods which in­duce the RF gen­er­a­tion. A spe­cial test bench for the char­ac­ter­i­za­tion of the de­vice with low RF power mea­sure­ments has been de­vel­oped. Per­formed mesure­ments of the scat­ter­ing pa­ram­e­ters and the elec­tric field pro­file along the struc­ture are care­ful­ly de­scribed. Fi­nal­ly, the pro­to­type has been in­stalled at CLEX, and first mea­sure­ments with beam are also re­port­ed.

• K.M. Schirm, S. Curt, S. Döbert, G. McMonagle, G. Rossat, I. Syratchev, L. Timeo
  CERN, Geneva
• A.A. Haase, A. Jensen, E.N. Jongewaard, C.D. Nantista, D.W. Sprehn, A.E. Vlieks
  SLAC, Menlo Park, California
• A. Hamdi, F. Peauger
  CEA, Gif-sur-Yvette
• S.V. Kuzikov, A.A. Vikharev
  IAP/RAS, Nizhny Novgorod

The CLIC RF fre­quen­cy has been changed in 2008 from the ini­tial 30 GHz to the Eu­ro­pean X-band 11.9942 GHz per­mit­ting beam in­de­pen­dent power pro­duc­tion using klystrons for CLIC ac­cel­er­at­ing struc­ture test­ing. A de­sign and fab­ri­ca­tion con­tract for five klystrons at that fre­quen­cy has been signed by dif­fer­ent par­ties with SLAC. France (CEA Saclay) is con­tribut­ing a solid state mod­u­la­tor pur­chased in in­dus­try to the CLIC study. RF puls­es over 120 MW peak at 230 ns length will be ob­tained by using a novel SLED I type pulse com­pres­sion scheme de­signed and fab­ri­cat­ed in Nizh­ny Nov­gorod, Rus­sia. The X-band power test stand has been in­stalled in the CLIC Test Fa­cil­i­ty CTF3 for in­de­pen­dent struc­ture and com­po­nent test­ing in a bunker, but al­low­ing, in a later stage, for pow­er­ing RF com­po­nents in the CTF3 beam lines. The de­sign of the fa­cil­i­ty, re­sults from com­mis­sion­ing of the RF power source and the per­for­mance of the Test Fa­cil­i­ty are re­port­ed.