LEP3: integration issues at the LHC tunnel

M. Koratzinos2nd LEP3 day,

23 October 2012

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

Civil engineering

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

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

John Osborne 5

Construction methods• Construction methods (standard):

– Tunnel boring machine (TBM)• Single pass precast segmental lining• Grout injection• 150m/week

– Roadheader • 30m/week

June 14th 2012

LHeCCDR

John Osborne 6

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)

500m

Point 1 - ATLASJunction Cavern

June 14th 2012

Junction Cavern

Point 5 - CMS

500m

120m

LHeCCDR

John Osborne 7

Costing and Planning Preliminary LHeC underground costs

June 14th 2012

Ring – Ring * Linac-Ring

P1 (Atlas) P5 (CMS) Total Total

Underground 40,156 38,445 78,602 226,983

Consultancy 4,059 3,886 7,946 22,945

Total KCHF 44,216 42,331 86,547 249,928

* 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.

LHeCCDR

John Osborne 8

Costing and Planning LHeC planning

LHeC construction planning YEAR 1 YEAR 2 YEAR 3 YEAR 4 YEAR 5 YEAR 6 YEAR 7

Land negotiations          

Environmental Impact Study

           

Building permits            

Detailed design & tendering            

Construction            

June 14th 2012

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)

LHeCCDR

Time and money

• For LHeC the cost of two tunnels of 2 kms length (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?

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?

Picture of a typical UA

…the other way

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

10MW L-Band MBK for European X-FEL

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

50cm

Real estate of Klystrons is modest

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.

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

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]

Cohabitation (with the LHC)

• Concurrent operation (LHeC style)

• Alternating operation (Y-to-Y or LS-to-LS)

• Single operation – only one accelerator in tunnel

Diffi

culty

Unnecessary

Currently the baseline

Best performance

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

LHeC S. Weisz referee report

Preparation of junction areas Completion of by- ‐passes - ‐ CE Installation of services - I‐ nfrastructure Installation of electron ring

4 years stop of LHC

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

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

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.

Integration of LEP3 around DFBs…

…would be a nightmare!

More DFB pictures

• LHC beam pipes are hiding behind the “chimneys”

The arcs

The QRL connection & IFS box

QRL connection – every 100 m

IFS box– every magnet

Tunnel space considerations

LH eC

: LHeC

: Space reserved for future e+e– machine

LEP3

LEP3

LEP3

LEP3

I have tried to be as open- minded as I could…

Position 1

LH eC LEP3

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

Position 2

LH eC

LEP3

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

Position 3

LH eC

LEP3

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

Position 4

LH eC

LEP3

On the floor. Easy fixing.Problems: mechanical fixing, remove QPS racks

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)

End