1. Tertiary Collimators in IP1/IP5 LARP Collaboration Meeting Pheasant Run, St. Charles, IL October 5-6, 2005 Fermilab LARP Collaboration Nikolai Mokhov, Fermilab

2. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov2 OUTLINE Tertiary Collimators Progress Since April’s Meeting Status and Plans

3. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov3 TERTIARY COLLIMATORS

4. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov4 DESIGN CONSTRAINTS

5. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov5 MARS15 SIMULATIONS IN IP5 WITH A SIMPLE BEAM LOSS MODEL

6. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov6 TERTIARY BEAM HALO LOSS IN IP5

7. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov7 FIRST MODELING WITH TWO COPPER TCTs

8. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov8 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 2x10 6 p/s.

9. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov9 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.

10. LARP – Pheasant Run, Oct. 5-6, 2005TCT Collimators - N.V. Mokhov10 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.