LEP3: integration issues at the LHC tunnel

1. LEP3: integration issues at the LHC tunnel M. Koratzinos 2nd LEP3 day, 23 October 2012

2. Preamble • This is not an exhaustive list of all issues. It is rather a first attempt to categorize integration issues • The aim is to come up with integration-related questions that we wish to study and answer (to complement the table that Frank and others have started compiling) • We are at the ‘brainstorming’ period. No idea is too crazy or too stupid. • I will try not to repeat what I have already reported on during the 1st LEP3 day

3. Civil engineering • The civil engineering that (might) be needed for LEP3 is for: • Klystron galleries • Bypass tunnels

4. Question #1: bypass tunnels • The accelerator ring could either pass through the experiments or bypass them. • The two options need to be studied: • Pass-through solution: what is the loss of performance? • Bypass tunnel: how much does it cost? • For the latter, we have a good idea from the LHeC design report

5. LHeC CDR Construction methods • Construction methods (standard): • Tunnel boring machine (TBM) • Single pass precast segmental lining • Grout injection • 150m/week • Roadheader • 30m/week John Osborne

6. LHeC CDR Civil Construction Ring-Ring scheme • Ring – Ring • New bypass tunnels on the outside of the LHC tunnel at Point 1 and Point 5 • Assumed no bypass tunnel needed at Point 8 (LHCb) Point 1 - ATLAS Junction Cavern Point 5 - CMS 500m Junction Cavern 120m 500m John Osborne

7. LHeC CDR Costing and Planning PreliminaryLHeC underground costs • * Ring-Ring costs do not include : Bypass tunnels at Point 8 (LHCb) or Injection Complex • No surface structures included in this cost estimate. Integration with other services (Cooling & Ventilation, Electricity etc) needed in the next phase to better define underground volumes and surface building requirements. Cost estimation by Amberg Engineering. John Osborne

8. LHeC CDR Costing and Planning LHeC planning • 4 year Construction schedule for either LHeC option: • Ring-ring: • Assuming 2 roadheaders with excavation progress of 30m/week • Linac-Ring: • Assuming 2 roadheaders and 1 shielded TBM (TBM excavation progress of 150m/week) John Osborne

9. Time and money • For LHeC the cost of two tunnels of 2 kmslength (plus 240m of klystron galleries) is 86MCHF • The time envisaged for construction is 4 years • The LHeC estimate is close to what we would need for LEP3 injector beam bypass • The question now becomes, does the loss of performance justify spending this amount of money?

10. Question #2: civil engineering for klystron galleries • Can we get away without extra civil engineering for the klystron galleries? • LEP2 klystron galleries (UAs) now filled with Power converters, UPSs, protection switches, vacuum control, etc., etc. • How many klystrons do we need and what real estate do they take?

11. Picture of a typical UA

12. …the other way

13. Klystron galleries • LEP3 needs 606m of RF cavities (900m of cryo modules) and a corresponding length of klystron galleries. • It is preferable from a cryo point o view if we split these in four (even) points. This means 150m of RF per even point. • Do not forget that LEP3 will also need 7GV of RF power for the injector ring (350m) or 90m per even point. • It is not excluded that a scheme will be found where both the accelerator and injector ring use the same RF cavities, but this needs a lot of brainstorming and real work. • Total is 120 m of RF both right and left of all even IP points. • One RF cavity is 1.03 m long. We need about 110 cavities per side and per even IP • For the main ring we need 1 klystron every 2 RF cavities. For the accelerator ring we only need 1 klystron per 8 or 16 cavities. • Total number of klystrons per side 85 + (5 to 10) = around 90 klystrons

14. 10MW L-Band MBK for European X-FEL 50cm Figures show the cut-away view of the Toshiba MBK E3736 and its photograph, respectively. The total length is approximately 2.3 m. 2.3m Real estate of Klystrons is modest

15. Klystron galleries • Need ~90 Klystrons per side per even IP • These need less than 90 m of space in the gallery. • UAs are more than 200 m long. • The LHC powering links project will help here • Careful study should be performed, but it should be feasible to integrate the klystons in the UAs.

16. The LHC powering links project • The idea is to move all power converters and the DFBs (cryogenic electrical feedboxes) to the surface • Reason: avoid SEU issues • Project is not yet approved but on track to be installed during LS2 and LS3 • This will benefit LEP3 is two ways: • Liberate real estate in the UAs for klystrons • Solve the problem of how to integrate LEP3 around the DFBs

17. Cohabitation issues • Reminder: three possible cohabitation scenarios with the LHC. • Our current baseline is for LEP3 to be installed while the bulk of the LHC magnets and infrastructure remains in the tunnel. • [in case it is decided to remove the LHC first and then install LEP3, the problem is non-existent]

18. Cohabitation (with the LHC) • Concurrent operation (LHeC style) • Alternating operation (Y-to-Y or LS-to-LS) • Single operation – only one accelerator in tunnel Unnecessary Difficulty Currently the baseline Best performance

19. The LHeC experience • What can we learn from the ring-ring exercise of the LHeC? • S. Weisz has looked at the ring-ring option and made a series a recommendations • Although the LEP3 case is different than the LHeC case, the recommendations need to be taken into account

20. LHeC S. Weisz referee report • From the summary paragraph: • Need to perform a precise integration study in the LSSs • Impact of the electron ring on the LHC protection systems • No show-stopper can be identified • Prevention and maintenance work might be a problem after HL-LHC • A stop of the LHC of at least 4 years Each column is 6 months 4 years stop of LHC • My personal conclusion from reading the report: • LHeC integration issues are much more important than those of LEP3 due to the need for concurrent operation • Although there is no showstopper, one needs to keep an eye on how to minimize the time where no accelerator would be running in the LHC tunnel. • LEP was installed in 18 months – LHeC seems to need 4 years

21. S. Wiesz extra input • Sylvain has the feeling that a co-habitation solution can be found in the arcs, but one needs to pay special attention in the long straight sections • Questions like DFB integration, RF module positioning, klystron positioning, etc. are the important questions to answer first.

22. Integration of LEP3 around DFBs… …would be a nightmare!

23. More DFB pictures • LHC beam pipes are hiding behind the “chimneys”

24. The arcs

25. The QRL connection & IFS box QRL connection – every 100 m IFS box– every magnet

26. Tunnel space considerations : LHeC : Space reserved for future e+e– machine LEP3 LEP3 LEP3 I have tried to be as open- minded as I could… LEP3

27. Position 1 On top of the LHC, as envisaged originally. Problems: mechanical fixing, vertical bump, need to avoid QRL “chimney” LEP3

28. Position 2 On the right of the LHC. Easy fixing, no vertical bump. Problems: can the LHC magnet train pass? LEP3

29. Position 3 On the left of the LHC. Problems: mechanical fixing, vertical bump, need to avoid QRL “chimney” LEP3

30. Position 4 On the floor. Easy fixing. Problems: mechanical fixing, remove QPS racks LEP3

31. Conclusions • Questions to add to our long list: • Experiment bypass tunnels: worth the extra cost? • Klystron galleries: can the real estate needed be found without civil engineering? • Investigate even crazy ideas of position of LEP3 in the arcs. • (questions from my talk during the 1st LEP3 day also remain)

32. End