• J. Stiller
  Heidelberg University, Heidelberg
• H.S. Matis, A. Ratti, W.C. Turner
  LBNL, Berkeley, California
• R. Miyamoto
  BNL, Upton, Long Island, New York
• S.M. White
  CERN, Geneva

The LHC BRAN lu­mi­nos­i­ty de­tec­tor mon­i­tors the high lu­mi­nos­i­ty in­ter­ac­tion re­gions (Atlas and CMS). This cham­ber, which is an Argon gas ion­iza­tion de­tec­tor mea­sures the for­ward neu­tral par­ti­cles from col­li­sions the in­ter­ac­tion re­gion. To pre­dict and im­prove the un­der­stand­ing of the de­tec­tor's per­for­mance, we pro­duced a de­tailed model of the de­tec­tor and its sur­round­ings in FLUKA. In this paper, we pre­sent the model and re­sults of our sim­u­la­tions in­clud­ing the de­tec­tor's es­ti­mat­ed re­sponse to in­ter­ac­tions for beam en­er­gies of 3.5, 5.0, and 7.0 TeV.

• A. Ratti, H.S. Matis, W.C. Turner
  LBNL, Berkeley, California
• E. Bravin, S.M. White
  CERN, Geneva
• R. Miyamoto
  BNL, Upton, Long Island, New York

The Lu­mi­nos­i­ty Mon­i­tor for the LHC is ready for op­er­a­tion dur­ing the planned 2009-2010 run. The de­vice de­signed for the high lu­mi­nos­i­ty re­gions is a gas ion­iza­tion cham­ber, that is de­signed with the abil­i­ty to re­solve bunch by bunch lu­mi­nos­i­ty as well as sur­vive ex­treme lev­els of ra­di­a­tion. The de­vices are in­stalled at the zero de­gree col­li­sion angle in the TAN ab­sorbers ±140m from the IP and mon­i­tor show­ers pro­duced by high en­er­gy neu­trons from the IP. They are used in real time as a col­lid­er op­er­a­tions tool for op­ti­miz­ing the lu­mi­nos­i­ty at ATLAS and CMS. A pho­to-mul­ti­pli­er based sys­tem is used at low lu­mi­nosi­ties and also avail­able. We will pre­sent early test re­sults, noise and back­ground stud­ies and cor­re­la­tion be­tween the gas ion­iza­tion and the PMT. Com­par­i­son with on­go­ing mod­el­ing ef­forts will be in­clud­ed.

• R. Tomás, O.S. Brüning, M. Giovannozzi, M. Lamont, F. Schmidt, G. Vanbavinckhove
  CERN, Geneva
• M. Aiba
  PSI, Villigen
• R. Calaga, R. Miyamoto
  BNL, Upton, Long Island, New York

Op­tics sta­bil­i­ty dur­ing all phas­es of op­er­a­tion is cru­cial for the LHC. The op­ti­cal prop­er­ties of the ma­chine have been op­ti­mized based on a de­tailed mag­net­ic model of the SC mag­nets and on their sort­ing. Tools and pro­ce­dures have been de­vel­oped for rapid checks of beta beat­ing, dis­per­sion, and lin­ear cou­pling, as well as for prompt op­tics cor­rec­tion. Ini­tial op­tics er­rors, cor­rec­tion per­for­mance and op­tics sta­bil­i­ty from the first LHC run will be re­port­ed, and com­pared with ex­pec­ta­tions. Pos­si­ble im­pli­ca­tions for the col­li­ma­tion clean­ing ef­fi­cien­cy and LHC ma­chine pro­tec­tion will be dis­cussed.

Slides

• R. Miyamoto
  BNL, Upton, Long Island, New York
• M. Cattin, J. Serrano, R. Tomás
  CERN, Geneva

The adi­a­batic­i­ty of the AC dipole might be com­pro­mised by noise or un­want­ed fre­quen­cy com­po­nents in its sig­nal. An ef­fort has been put to char­ac­ter­ize and op­ti­mize the sig­nal qual­i­ty of the LHC AC dipoles. The mea­sured sig­nal is used in re­al­is­tic sim­u­la­tions in order to eval­u­ate its im­pact on beam dy­nam­ics and to ul­ti­mate­ly es­tab­lish safe mar­gins for the op­er­a­tion of the LHC AC dipoles.