• D. Wollmann, O. Aberle, G. Arnau-Izquierdo, R.W. Assmann, J.-P. Bacher, V. Baglin, G. Bellodi, A. Bertarelli, A.P. Bouzoud, C. Bracco, R. Bruce, M. Brugger, S. Calatroni, F. Caspers, F. Cerutti, R. Chamizo, A. Cherif, E. Chiaveri, P. Chiggiato, A. Dallocchio, R. De Morais Amaral, B. Dehning, M. Donze, A. Ferrari, R. Folch, P. Francon, P. Gander, J.-M. Geisser, A. Grudiev, E.B. Holzer, D. Jacquet, J.B. Jeanneret, J.M. Jimenez, M. Jonker, J.M. Jowett, Y. Kadi, K. Kershaw, L. Lari, J. Lendaro, F. Loprete, R. Losito, M. Magistris, M. Malabaila, A. Marsili, A. Masi, S.J. Mathot, M. Mayer, C.C. Mitifiot, N. Mounet, E. Métral, A. Nordt, R. Perret, S. Perrollaz, C. Rathjen, S. Redaelli, G. Robert-Demolaize, S. Roesler, A. Rossi, B. Salvant, M. Santana-Leitner, I. Sexton, P. Sievers, T. Tardy, M.A. Timmins, E. Tsoulou, E. Veyrunes, H. Vincke, V. Vlachoudis, V. Vuillemin, Th. Weiler, F. Zimmermann
  CERN, Geneva
• I. Baishev, I.A. Kurochkin
  IHEP Protvino, Protvino, Moscow Region
• D. Kaltchev
  TRIUMF, Vancouver

The LHC has two ded­i­cat­ed clean­ing in­ser­tions: IR3 for mo­men­tum clean­ing and IR7 for be­ta­tron clean­ing. The col­li­ma­tion sys­tem has been spec­i­fied and built with tight me­chan­i­cal tol­er­ances (e.g. jaw flat­ness ~ 40 μm) and is de­signed to achieve a high ac­cu­ra­cy and re­pro­ducibil­i­ty of the jaw po­si­tions. The prac­ti­cal­ly achiev­able clean­ing ef­fi­cien­cy of the pre­sent Phase-I sys­tem de­pends on the pre­ci­sion of the jaw cen­ter­ing around the beam, the ac­cu­ra­cy of the gap size and the jaw par­al­lelism against the beam. The re­pro­ducibil­i­ty and sta­bil­i­ty of the sys­tem is im­por­tant to avoid the fre­quent rep­e­ti­tion of beam based align­ment which is cur­rent­ly a lengthy pro­ce­dure. With­in this paper we de­scribe the method used for the beam based align­ment of the LHC col­li­ma­tion sys­tem, its achieved ac­cu­ra­cy and sta­bil­i­ty and its per­for­mance at 450GeV.

Slides

• S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
  Karlsruhe Institute of Technology (KIT), Karlsruhe
• V. Baglin
  CERN, Geneva
• C. Boffo, G. Sikler
  BNG, Würzburg
• T.W. Bradshaw
  STFC/RAL, Chilton, Didcot, Oxon
• R. Cimino, M. Commisso, B. Spataro
  INFN/LNF, Frascati (Roma)
• J.A. Clarke, D.J. Scott
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• M.P. Cox, J.C. Schouten
  Diamond, Oxfordshire
• R.M. Jones, I.R.R. Shinton
  UMAN, Manchester
• A. Mostacci
  Rome University La Sapienza, Roma
• E.J. Wallén
  MAX-lab, Lund
• R. Weigel
  Max-Planck Institute for Metal Research, Stuttgart

One of the still open is­sues for the de­vel­op­ment of su­per­con­duct­ing in­ser­tion de­vices is the un­der­stand­ing of the beam heat load. With the aim of mea­sur­ing the beam heat load to a cold bore and the hope to gain a deep­er un­der­stand­ing in the beam heat load mech­a­nisms, a cold vac­u­um cham­ber for di­ag­nos­tics is under con­struc­tion. The fol­low­ing di­ag­nos­tics will be im­ple­ment­ed: i) re­tard­ing field an­a­lyz­ers to mea­sure the elec­tron flux, ii) tem­per­a­ture sen­sors to mea­sure the total heat load, iii) pres­sure gauges, iv) and mass spec­trom­e­ters to mea­sure the gas con­tent. The inner vac­u­um cham­ber will be re­mov­able in order to test dif­fer­ent ge­ome­tries and ma­te­ri­als. This will allow the in­stal­la­tion of the cryo­stat in dif­fer­ent syn­chrotron light sources. COLD­DI­AG will be built to fit in a short straight sec­tion at ANKA. A first in­stal­la­tion at the syn­chrotron light source DI­A­MOND is under dis­cus­sion. Here we de­scribe the tech­ni­cal de­sign re­port of this de­vice and the planned mea­sure­ments with beam.

• V. Baglin, G. Bregliozzi, J.M. Jimenez
  CERN, Geneva

At the start of the CERN Large Hadron Col­lid­er (LHC) 2008-2009 shut­down, all the LHC ex­per­i­men­tal vac­u­um cham­bers were vent­ed to neon at­mo­sphere. They were later pumped down short­ly be­fore beam cir­cu­la­tion. In par­al­lel, 2.3 km of vac­u­um beam pipes with NEG coat­ings were vent­ed to air and re-ac­ti­vat­ed to allow the in­stal­la­tion or re­pair of sev­er­al com­po­nents such as roman pots, kick­ers, col­li­ma­tors, rup­ture disks and masks and re-ac­ti­vat­ed there­after. Be­side these stan­dard op­er­a­tions, "fast ex­changes" of vac­u­um com­po­nents and en­do­scopies in­side cryo­genic beam vac­u­um cham­bers were per­formed. This paper pre­sents a sum­ma­ry of all the ac­tiv­i­ties held dur­ing this pe­ri­od and the achieved vac­u­um per­for­mances.

• V. Baglin, G. Bregliozzi, J.M. Jimenez
  CERN, Geneva
• J. Kamiya
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

Pres­sure in­creas­es are ob­served with the first beams cir­cu­lat­ing in the CERN Large Hadron Col­lid­er (LHC) close to some col­li­ma­tors. This paper de­scribes the vac­u­um per­for­mances of the col­li­ma­tors as mea­sured in the lab­o­ra­to­ry and also the per­for­mances ob­tained in the ma­chine. Based on these ob­ser­va­tions, es­ti­ma­tions of some op­er­a­tional be­hav­ior such as pres­sure in­crease and NEG re­ac­ti­va­tion sce­nario are given.

• V. Baglin, B. Henrist, B. Jenninger, J.M. Jimenez, E. Mahner, G. Schneider, A. Sinturel, A. Vidal
  CERN, Geneva

Dur­ing the sec­tor 3-4 in­ci­dent, the two aper­tures of the 3 km long cryo­genic vac­u­um sec­tors of the CERN Large Hadron Col­lid­er (LHC) were bru­tal­ly vent­ed to he­li­um. A sys­tem­at­ic vi­su­al in­spec­tion of the beam pipe re­vealed the pres­ence of soot, metal­lic de­bris and super in­su­la­tion de­bris. After four month of clean­ing, the beam vac­u­um sys­tem was re­cov­ered. This paper de­scribes the tools and method­olo­gies de­vel­oped dur­ing this pe­ri­od, the achieved per­for­mances and dis­cuss­es pos­si­ble up­grades.