1 / 6

Present Approach and Status

Present Approach and Status. R. Assmann for the LHC Collimation Team. Problem: Al/Cu system would not resist irregular dumps (pre-trigger or asynchronous) and low beam lifetimes, even during early physics. Solution: Low Z material: More robust but longer.

deion
Download Presentation

Present Approach and Status

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Present Approach and Status R. Assmann for the LHC Collimation Team Problem: Al/Cu system would not resist irregular dumps (pre-trigger or asynchronous) and low beam lifetimes, even during early physics. Solution: Low Z material: More robust but longer. Progress: Sep 2001 LHC Beam Cleaning Study Group Jan 2002 Consensus to consider low Z material (impedance presented as non-critical) Jun 2002 Consensus on detailed requirements First tolerances Oct 2002 Project LHC Collimation, AB/ATB Jan 2003 Full simulation chain: Beam – FLUKA – ANSYS Cleaning efficiency and optics with low Z Review of impedance, other constraints

  2. Our strategy: Find the simplest solution that is compatible with the requirements of the nominal LHC. (Carbon?!) Concentrate most effort into advancing these simple solutions. Keep more complicated/less convenient concepts in mind as backup solutions. (Beryllium, Diamond, multi-layer structures, crystal collimation, renewable high-Z collimators, repairable high-Z collimators, tertiary collimators at the triplets, primary collimators covering the phase space, anti-kicker at dump …) Some “backup solutions” might help to relax operational tolerances or help for machine protection.

  3. Feb 2003: Signs of convergence? (worst case shock beam impact) FLUKA: C seems best choice, better than Be higher Z is out of question 100 mm higher-Z coating seems unfeasible Copper structure after 1 cm C seems OK ANSYS: Simple C a factor 2-3 too low in robustness (OK for first years of LHC, 1 bunch out of 3) Other forms (carbon-carbon) under study (better?). Lengths: 0.2 m and 1.0 m long C jaws OK for efficiency first preliminary optics re-match looks good Radiation: Peak activation lower (avoid remote handling) First detailed results for BLM response All based on our consensus on low Z.

  4. AP worries for fundamental system design: Impedance: Reviewed in Jan 03. More details today… E-cloud: First discussion Jan 03. No estimate yet. SNS: TiN coating on all collimators Special solenoids in collimator locations Additional worries on operational, technical, engineering issues (not for now). Goal: Decide jaw design and material(s) in April 03. Fix fundamental constraints from impedance, local e-cloud as soon as possible! There are alternatives to low Z, but fundamental concept is changed.

  5. Collimators & absorbers at 7 TeV: • Numbers are for Al, Cu system. Length is given per collimator • All collimators two-sided except noted. • Number is per beam. • TCL (D2) is an upgrade for LHC ultimate performance. • Table is for 7 TeV. • Settings are for nominal luminosity and nominal b* (n1 = 7 in the triplet). • For injection add TDI, TCL (inj), and TCDS. All around 10 s. IR1 and IR5 settings could be open for injection, others remain at similar settings.

  6. Collimators & absorbers at 7 TeV (C-based system):

More Related