Collimation System Update

1. Collimation System Update R. Assmann, AB LHC MAC June 15th, 2007

2. The LHC Collimation System Phase # elementsInitial 94 Upgrade 1 44(all prepared) Upgrade 2 22 • System is powerful but complex: • 160 locations in the ring. • 28 locations in the transfer line. • 8 types of collimators plus various types of masks and absorbers. • A path is defined from initial to nominal and ultimate intensities (upgrades). • Different interfaces depending on neighboring equipment and on level of induced radioactivity.

3. System Overview “Phase 1” Momentum Cleaning Betatron Cleaning “Final” system: Layount is 100% frozen!

4. Functional Description • Two-stage cleaning (robust CFC primary and secondary collimators). • Catching the cleaning-induced showers (Cu/W collimators). • Protecting the warm magnets against heat and radiation (passive absorbers). • Local cleaning and protection at triplets (Cu/W collimators). • Catching the p-p induced showers (Cu collimators). • Intercepting mis-injected beam (TCDI, TDI, TCLI). • Intercepting dumped beam (TCDQ, TCS.TCDQ). • Scraping and halo diagnostics (primary collimators andthin scrapers).

5. The LHC “TCSG” Collimator 1.2 m 360 MJ proton beam 3 mm beam passage with RF contacts for guiding image currents Designed for maximum robustness: Advanced CC jaws with water cooling! Other types: Mostly with different jaw materials. Some very different with 2 beams!  For design see TS seminar A. Bertarelli.

6. Hardware Procurement... Major contracts: Collimators (FR) Motors and sensors (D) Position sensors (FR/China) CFC (J) Supports (Bulgaria) Vacuum pumping ports (Italy) Material/screws (Switzerland) Glidcop material (US) PXI low level controls (H/US) Motor drivers + supplies (Italy)

7. Status of Collimator Procurement Phase # elementsInitial 94 (ring) + 24 (TL) Upgrade 1 44(all prepared) Upgrade 2 22 • The 118 collimators and absorbers for the initial phase must be procured: • Series production ongoing for the initial phase: • Industry: 108 in total(including 6 upgrade collimators)80 ring collimators (+12 spares) and 14 transfer line collimators (+ 2 spares). • CERN: 32 in total(including 8 collimators taken over from CERCA)18 ring collimators/absorbers (+ 4 spares) and 10 transfer line masks (including 2 TCDD, 2 TCLIM, 8 TCAP) (including 4 TCLP, 8 TCHS, 2 TCLA)

8. Industrial Production Production has just reached its peak rate of 12 collimators per month! The production crisis during the second half of 2006 has been overcome!

9. Industrial Production (Integrated) spares Crisis We have received 1/3 of the collimators from industry. October 2007: All collimators for installation can be available, if no other crisis! There was a production crisis from July to December 2006!

10. Problem Collection I Brazing Coating RF fingers Ni-Cu coating Vacuum feedthroughs TS/MME analysis of problems

11. Production Collection 2 Oil Pollution Welding RF fingers AT/VAC and TS/MME analysis of problems

12. Overcoming the Crisis... • Production of conform collimators stopped in August 2006 due to severe quality problems in the production company. Main problems: • Machining of UHV parts with oil-based cooling fluids. • Insufficient UHV cleaning. • Non-conform surface coating and brazing problems. • Lack of quality control from contractor. • Problems appeared when production rate was supposed to go up. • Status August 2006: 14 collimators produced, 8 only acceptable. • Strong TS involvement starting in September 2006 to correct situation together with AB and AT: • Review, documentation and transfer of all detailed CERN procedures, as used for construction of prototype collimators in TS. • Somecritical production steps done at CERN while contractor corrects problems. • TS/MME leading production control on site of contractor and sub-contractors. • AT/VAC program to establish UHV:15 tests of collimators components made between 6/11/06 and 6/12/06 + assistance in Romans to CERCA.  • Quite some effort required: 1600 TS staff hours from Oct-Dec 2006 plus important AB/AT resources. TS/MME and AT/VAC presence at CERCA during Christmas holidays.

13. Achievements • All technical issues solved and production was restarted. • Collimator quality acceptable but not perfect for first 2007 collimators (e.g. only partial tank cooling for some collimators)  handled without impact on collimation performance (e.g. locating first collimators at low power locations or repairing at CERN). • Peak production rate of 12 collimators in 1 monthwas achieved in May. • Collimator production is in industrial mode. • The full minimal system is at CERN (basic two-stage betatron and momentum cleaning)  ready for originally foreseen 450 GeV run and up to ~15 nominal bunches at 7 TeV. • Production now focuses on W collimators. In September 2007: • cleaning performance reach at ~20% of nominal intensity. • triplet protection collimators available.

14. Production Process Tanks Jaw supports Parts Bellows Pressure tests Cleaning Company has built a stock of pre-assembled parts. Procedures in place.

15. Production Process Mechanical table Assembled collimator Jaw assembly Brazing control Alignment & calibration Collimators are handled in parallel at their different stages  higher rate!

16. Production Process EB welding Packed & ready for shipment Vacuum & bakeout

17. Workflow Workflow

18. Completion Other Components I • Supports and quick plug-ins: • All phase 1 standard supports installed.Allmost all completed with plug-in: final work in LSS7R ongoing (waiting for completion of warm magnet tests). • Alignment campaign planned (next week LSS1 then LSS7). • Phase 2 base supports are at CERN but installation to be completed. • Cabling electrical plug-in: 100 out of 112 are ready. • Cooling water: All tappings with valves installed. Special flexibles are at CERN, standard flexibles from TS/CV. Connection, adjustment, final pressure test to be done. • Radiation hard stepping motors and resolvers (50 MGy): • All ~550 at CERN. Rejection for ~50, due to insufficient insulation of resolvers. • Position sensors LVDT‘s: • 750/750 produced and tested. 5 rejected. Ready for mounting. • Microswitches: • 1500/1500 produced and tested.

19. Completion Other Components II • Cabling: • Long cables all ordered in standard campaign. All installed except LSS2. • Final ~5 m cable connections (radiation hard) all ordered by TS/EL. Installed in LSS3 and few other positions (LSS8 and TI8). • Cables of interconnection among racks (interlocks, triggers, timing, ...) all ordered (TS/EL) but not installed yet. • Racks: • Racks all installed in the 7 IR‘s with collimators. • Stepping motor drivers: • 10/510 ready. 100 more will arrive next Tuesday. Not critical (all there in September) • Delay due to EM emission and long cable required modifications. Now fixed. • PXI low level controls: • All delivered by NI. Outside of main tunnel

20. Other Procurement First series production of stepping motors with 50 MGy radiation-hardness. High numbers now available for mounting on collimators. Design based on ITER R&D and early prototyping. Solution was adapted to CERN needs and transformed into industrial process (9 month effort AB/ATB + industry).

21. Cooling Water Issues • Manifolds for water connection at collimator support were found to have bad welding: No issue for the early years but we must replace them to avoid problems in some years. Try to do it before 2008 startup but not required.. • Cooling water in the collimator must be regulated with an accuracy of about 10%: • Water velocity must be high enough to handle heat loads from the beam (up to 7kW – is a function of beam intensity and loss rates). • Water velocity must be lower than 3 m/s to avoid erosion/corrosion. • Water loads will change after any change in collimator complement (upgrade). • Prototype tests for radiation-hard regulation valves are ongoing. Procurement in August - October and installation in October/November (no impact on vacuum integrity). • No showstopper (can always implement a temporary solution) but we are watching this carefully…

22. Final Assembly at CERN spares Industrial production Final assembly completed! Final assembly restarted with full speed end of April. Major effort AB/ATB group. Collimators can be installed after leaving the final assembly hall in B.252!  So far 10 collimators installed!

23. Acceptance at CERN

24. Example: Criteria

25. Support & Plug-In Installation LSS5 Almost all ready in the 7 IR‘s with collimators. Survey and alignment done with quick-plugin supports and without collimator (precise reference from plug-in and alignment tool).

26. Collimator Installation Preparation Delroux et al

27. Collimator Installation Quick plug-in support (10 min installation)

28. Ring Collimators Installed in IR6 IR6 collimators are part of the dump protection system of the LHC. Special installation due to space constraints with the dump line. These 2 like some others with only partial tank cooling (welding problem on tank: predicted to be no problem as low heat load expected).

29. Collimator Transport Vehicle  Start of training for collimator installation with upgraded vehicle (K. Kershaw et al).

30. Collimator Installation • All required installation tools are operational. • Collimators are being produced at higher rate now. May was a very important milestone. Most difficult collimator design (8 two-beam collimators) likely transferred to CERN production. • A detailed production planning up to the end will be provided by the company by mid-June (difficult). Somehow mixed with contractual negotiations. • Planning for not-completed in-house production is being established with TS (depends on decisions with CERCA). • Optimized collimator installation planning is being worked out with the LHC installation planning group: • Install the collimators we receive up to January 2008 to have complete collimation system for 2008 run. Compatibility with production progress. • Minimize interference with other work: group by vacuum sectors, synchronize with vacuum workflow, synchronize with alignment, HWC constraints, ….

31. Production Priorities Draft I J. Coupard et al

32. Production Priorities Draft II J. Coupard et al

33. Draft Sequence: Optimized Installation-Readiness LSS3/7(Jan - Jun 07) LSS6(Feb 07) TI2/LSS8(May - Jul 06) Present status: The minimal system is there. LSS5(Jul 07) TI8(Jul - Aug 07) LSS3/7(Aug - Oct 07) Ready for high intensities but not high activation. Planning quite uncertain: detailed planning from CERCA needed, including material status. LSS1(Oct - Nov 07) LSS2(Nov 07) LSS2/8(Oct 07) LSS1(Nov 07) LSS2(Nov 07) LSS5(Nov 07) January 2008: Goal is full phase 1 completion. Ready for high activation, high luminosity, non-standard b*. LSS3/7(Jan 08) LSS8(Nov - Dec 07) Ongoing work. Being optimized further… Sequence of vacuum sectors exists.

34. Conclusion I • The collimator production crisis has been overcome. Production reached a peak value of 12 per month. Must work hard to keep it there… • Procurement of extensive auxiliary equipment (sensors, motors, local infrastructure, …) is in good shape. • Increased pressure on CERN work: Final assembly at CERN has restarted and is going full speed for 3 collimators per week (~8 persons full time). • Full minimal system is at CERN and is being prepared for installation (ready for up to 15 nominal bunches at 7 TeV). 8 collimators stored for installation (IR3 and IR7). • All quick-plugin supports available/installed (final LSS7R ongoing). • Collimator alignment campaign will start next week in LSS1 and then move to LSS7. • High rate collimator installation is being prepared (installation training). 10 already installed. IR7 installation starts in July…

35. Conclusion II • Many tests without and with beam show that LHC collimators are robust, reliable (20,000 cycles) and precisely controllable. The 118 initial LHC collimators/absorbers should advance the state-of-the-art by ~2 orders of magnitude. • Goals: Have almost the full phase 1 system ready for the 2008 run. Full passive protection, high cleaning efficiency (> 99.99%) will then be there. Last collimators for installation ready in January 2008. • These goals are achievable if we can keep the present pace. We still have a way to go and there are always risks… We will work hard to make these goals. • Requires some effort to integrate late collimator installation with other activities. • Optimized installation planning is being worked out with the LHC installation planning group. Detailed schedules still in flux (negotiations affect schedule and in-house work). • Ongoing work in other areas not discussed here: hardware commissioning, controls system, preparation for beam commissioning and operation, accelerator physics studies, radiation tests, cascade modeling, preparations for upgrades (performance, remote handling, …).