• R. Tomás, B. Dalena, E. Marin, D. Schulte, G. Zamudio
  CERN, Geneva
• D. Angal-Kalinin, J.-L. Fernandez-Hernando, F. Jackson
  Cockcroft Institute, Warrington, Cheshire
• J. Resta-López
  JAI, Oxford
• A. Seryi
  SLAC, Menlo Park, California

The CLIC Con­cep­tu­al De­sign Re­port must be ready by 2010. This paper aims at ad­dress­ing all the crit­i­cal points of the CLIC BDS to be later im­ple­ment­ed in the CDR. This in­cludes risk eval­u­a­tion and pos­si­ble so­lu­tions to a num­ber of se­lect­ed points. The smooth and prac­ti­cal tran­si­tion be­tween the 500 GeV CLIC and the de­sign en­er­gy of 3 TeV is also stud­ied.

• J.-L. Fernandez-Hernando, D. Angal-Kalinin
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

The pro­posed UK New Light Source pro­ject will need beam dump to ab­sorb a bunch charge of 200 pC with the rep­e­ti­tion rates start­ing from 1 KHz ini­tial­ly up to 1 MHz in the up­grade. We are ex­plor­ing an op­tion of a solid dump with a graphite core to ab­sorb the beam power up to 450 kW for the up­grade op­tion as this is the most chal­leng­ing de­sign. Since the beam dump de­sign will also af­fect the build­ing lay­out the choice of its de­sign should be made at an early stage. Based on the fea­si­bil­i­ty stud­ies of a solid dump, a de­ci­sion not to go for more com­plex water dump can be taken. The post linac col­li­ma­tion sec­tion should pro­tect the un­du­la­tors from ir­ra­di­a­tion due to beam halo par­ti­cles. This paper shows re­sults and con­clu­sions from sim­u­la­tions of the im­pact of the NLS beam on dif­fer­ent solid beam dump so­lu­tions and the ef­fect of the beam halo on the col­li­ma­tors.

• J. Resta-López
  JAI, Oxford
• D. Angal-Kalinin, J.-L. Fernandez-Hernando, F. Jackson
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• B. Dalena, D. Schulte, R. Tomás
  CERN, Geneva
• A. Seryi
  SLAC, Menlo Park, California

Im­por­tant ef­forts have re­cent­ly been ded­i­cat­ed to the im­prove­ment of the de­sign of the base­line col­li­ma­tion sys­tem of the Com­pact Lin­ear Col­lid­er (CLIC). Dif­fer­ent as­pects of the de­sign have been op­ti­mized: the trans­verse col­li­ma­tion depths have been re­cal­cu­lat­ed in order to re­duce the col­li­ma­tor wake­field ef­fects while main­tain­ing a good ef­fi­cien­cy in clean­ing the un­de­sired beam halo; the ge­o­met­ric de­sign of the spoil­ers have also been re­viewed to min­i­mize wake­fields; in ad­di­tion, the op­tics de­sign have been pol­ished to im­prove the col­li­ma­tion ef­fi­cien­cy. This paper de­scribes the cur­rent sta­tus of the CLIC col­li­ma­tion sys­tem after this op­ti­miza­tion.

• A.E. Wheelhouse, C.D. Beard, P. Davies, J.-L. Fernandez-Hernando, E. Frangleton, P.A. McIntosh, A.J. Moss, J.F. Orrett
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• S.A. Belomestnykh, P. Quigley, V. Veshcherevich
  CLASSE, Ithaca, New York
• M.A. Cordwell, J. Strachan
  STFC/DL, Daresbury, Warrington, Cheshire

The Dares­bury in­ter­na­tion­al Cry­omod­ule Col­lab­o­ra­tion re­quires a suit­able RF cou­pler that will fit into the foot­print of the ALICE cry­omod­ule, with the abil­i­ty of trans­fer­ing po­ten­tial­ly up to 30 kW CW of RF power into the cav­i­ty whilst max­imis­ing the ca­pa­bil­i­ty for ad­just­ing the cou­pling. For this a mod­i­fied Cor­nell In­jec­tor cou­pler has been used. Mod­i­fi­ca­tions to the cold sec­tion was car­ried out. These cou­plers have now been as­sem­bled into a test cav­i­ty and con­di­tioned to 30 kW pulsed, 10 kW CW. This paper de­scribes the mod­i­fi­ca­tions re­quired to fit in­side the cry­omod­ule and de­tails of the tests that were car­ried out.

• J.-L. Fernandez-Hernando
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• J. Resta-López
  JAI, Oxford

Beryl­li­um is being con­sid­ered as an op­tion ma­te­ri­al for the CLIC en­er­gy col­li­ma­tors in the Beam De­liv­ery Sys­tem. Its high elec­tri­cal and ther­mal con­duc­tiv­i­ty to­geth­er with a large ra­di­a­tion length com­pared to other met­als makes Beryl­li­um an op­ti­mal can­di­date for a long ta­pered de­sign col­li­ma­tor that will not gen­er­ate high wake­fields, which might de­grade the orbit sta­bil­i­ty and di­lute the beam emit­tance, and in case of the beam im­pact­ing the col­li­ma­tor tem­per­a­ture rises will not be suf­fi­cient enough to melt the metal. This paper shows re­sults and con­clu­sions from sim­u­la­tions of the im­pact of a CLIC bunch train hit­ting the col­li­ma­tor.