Tertiary Collimators in IP1/IP5

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Tertiary Collimators in IP1/IP5
LARP Collaboration
Fermilab
Nikolai Mokhov, Fermilab

• LARP Collaboration Meeting
• Pheasant Run, St. Charles, IL
• October 5-6, 2005

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OUTLINE

• Tertiary Collimators
• Progress Since Aprils Meeting
• Status and Plans

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TERTIARY COLLIMATORS
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DESIGN CONSTRAINTS
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MARS15 SIMULATIONS IN IP5 WITH A SIMPLE BEAM LOSS
MODEL
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TERTIARY BEAM HALO LOSS IN IP5
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FIRST MODELING WITH TWO COPPER TCTs
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MARS15 RESULTS FOR COPPER TCTs
Peak power density is 0.35 mW/g in Q3. Particle
fluxes on CMS similar to those from earlier
studied accelerator backgrounds. Conclusion
keep TCT scraping rates below 2x106 p/s.
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PROGRESS SINCE APRIL

• MARS15 runs without TCTs and with copper and
  tungsten TCTs clear effect of TCTs their
  efficacy needs to be improved difference between
  tungsten and copper jaws is not definitive.
• A file of spray from copper TCT, entering the CMS
  hall, has been generated in June and sent to CMS
  colleagues.
• Desperately needed a file of realistic beam loss
  patterns in the TCT region for the latest LHC
  lattice, with IP3/IP7 collimators in, and updated
  vacuum map. Promised by CERN group since end of
  2004.
• On September 30, 2005, received such a file from
  Ralph for betatron cleaning for BEAM1.

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PLANS

• Complication BEAM1 is most important for IP1
  (spray from limiting apertures in IP8), while
  BEAM2 is most important for IP5 (halo goes from
  IP7 through IP6). MARS15 model is most advanced
  for IP5, with CMS team desperately waiting for
  results of simulation.
• Start MARS work with that file in mid-October
  update IP1 model, tests and optimization of
  tertiary collimators with respect to both
  radiation loads to inner triplet quads and
  background fluxes on the collider detectors.
• Need similar beam loss maps for momentum
  cleaning.
• Need beam loss maps for BEAM2 both for betatron
  and momentum cleaning.