1. Extract from today’s talk given to DCB
BDS layout
Extract from today’s talk given to DCB
August 22
Full version at
August 22, 2006
Global Design Effort

2. Tentative layout of 14/14 configuration
Common IR hall 100L*30Wm at z=0 with 28.4m separation of IPs
15m shafts equipped with elevator and stares in IR hall
4m tunnels in all BDS
Straight tunnel which goes to IR1 (for multi TeV)
Tunnel going to IR2 follows the beamline
Alcoves 4*6m every 100m, no service tunnel
Halls for dump cooling system 35*20m
Small 0.8m shaft for lasers near laser wire, upstream and downstream diagnostics
Passages near muon walls (main and spare one)
9m machine access shaft near BSY
Shortened extraction line
Shorter tapered tunnels. Etc.
Aug 22, 06
Global Design Effort

3. CF&S cost minimization considerations in new layout
Removing service tunnel and use alcoves
Reducing tunnel diameter from 5m to 4m
(use the fact that swing of BDS in 20/14mr is smaller than in 2mr)
Reduce BSY tunnel separation to 3m
Assume that CF&S will change methodology of tapered tunnel costing
Remove detector service cavern
Minimize number of shafts in IR
Cost min collider hall, assign the difference to detector (to be discussed with Detector colleagues)
Removing cost of e+ bypass line from BDS
Aug 22, 06
Global Design Effort

4. Tunnel with alcoves
If alcoves of 4*6*4m3 are placed every 100m, the cost of the single tunnel seem to increase by 10-20%
The interval of 100m is determined by BPM electronics, and cable cost. Finding the optimum dL and alcove size requires more study
To evaluate the cost difference, one need to add
cost of any additional shafts (assess and “laser shafts”), their caverns, surface buildings
cost of alcoves in all tunnels (including e+ if it is present)
cost of vibration mitigations for pumps
any additional air cooling which may be required
etc.
Without the service tunnel, the reliability and tune-ability of the system are affected, but it is hard to estimate the corresponding cost impact
Aug 22, 06
Global Design Effort

5. T stability
For beamline stability, set a goal of <100W/m deposition into the tunnel (like in best light sources)
Would like to have
Air: 0.2degC over 1hour, 2degC over 24hours
LCW: 0.1degC over 1hour, 1degC over 24hours
But do not yet know what the cost of these reqts
With alcoves, this is more of an issue
The absolute T also matters
if T is too high at work, and need to drop T during access, this is major stability concern
Under discussion now
Aug 22, 06
Global Design Effort

6. Tunnel diameter in 14/14 In 2/20 config, was using 5m tunnel
swing of 2mrad BDS was somewhat larger, due to design constraints, than in 20mr, and wanted to use straight tunnels in BDS (for upgrade flexibility)
One can now consider 4m tunnels
Still, have straight tunnel from the linac to IR1 (for Multi-TeV upgrade compatibility)
One can allow that tunnel would follow the beamline of IR2
(Reducing tunnel diameter also reduce the muon spoiler size and its cost by 30%)
Aug 22, 06
Global Design Effort

7. Layout with 4m tunnel This tunnel slightly follows the beamline
This tunnel is straight
(for multi-TeV)
(except minor knee near IP)
Aug 22, 06
Global Design Effort

8. BSY tunnel separation 3m
3m separation seems sufficient for FNAL-type rock [F.Asiri & J.Cogan]
This reduce the length of the tapered tunnel
Aug 22, 06
Global Design Effort

9. Tapered tunnel costing
=>
Cost separately the part which will be done by TBM and only remaining part by drill&blast
This whole volume was costed as drill&blast
Aug 22, 06
Global Design Effort

10. Removal of detector service cavern
layout as of Vancouver
In Vancouver layout, have a service cavern between collider hall, to place detector equipment and service
The need for such cavern for e+e- machine need to be re-evaluated
(in e+e- do not have triggers, so do not have to place a lot of electronics close to detector)
Suggest to remove the service cavern (and its shaft) and place all needed detector equipment in the collider hall
Aug 22, 06
Global Design Effort

11. Minimize number of shafts in IR
Do not install additional shafts in IR hall except two 15m shafts
Equip those 15m shafts with stairs & elevators
Example from GLD [Yasuhiro Sugimoto, KEK]
Aug 22, 06
Global Design Effort

12. Minimize number of shafts in IR
elevator
stairs
pipes
cable trays
Equip main IR shaft with elevator and stairs and use it for personnel access as well.
Do not install any other 9m shafts hear IR hall
11.4m
3.6m
15m
Aug 22, 06
Global Design Effort

13. Shaft cap on surface
partial cap on surface
solenoid (or other piece) before lowering down by gantry crane is sitting on the cap
For e+e- machine do not have to use shaft cap even if detector not self-shielded. Partial cap is needed to allow CMS style assembly.
Aug 22, 06
Global Design Effort

14. Discussion of IR hall cost assignment
Requirements for collider hall sizes are different and range from 48L*18Wm to 72L*32W m^2, as well as for the shaft
In order to make more clear comparison of detectors and streamline the overall optimization, one can consider the following suggestion:
Include into the BDS cost only the cost of minimum size collider hall and small shaft
for example, 100L*20W*30H m^3 hall, and two 9m shafts, no wall
The cost difference from min configuration is included into detector cost
E.g. D cost of increasing the shafts to 15m and increasing the hall size, and adding the shielding wall
Aug 22, 06
Global Design Effort

15. Details of the new layout
Small (0.8m) shafts for laser wire and polarimeters
On surface buildings with laser rooms
Aug 22, 06
Global Design Effort

16. Details of the new layout
Small (0.8m) shaft for laser for downstream polarimeter.
Transverse straight pass through rock to IR2 to another polarimeter.
On surface buildings with laser rooms
Tunnel “knee” to reduce volume of tapered tunnel (still straight path for multi-TeV is OK)
Extraction line is shortened by 100m,
relying more on beam sweeping to avoid
water boiling and window damage
(photons not swept, but their size is acceptably large)
Aug 22, 06
Global Design Effort

17. Details of the new layout
Passages around the 5m muon wall (the magnetized walls penetrate into the tunnel by ~0.5m) needed for personnel access, equipment transportation and alignment.
Passages are long enough, allowing installing extra muon wall (up to baseline 18m) if needed
5m wall
Passages around the muon wall which is not installed initially, but can be installed in upgrade (up to baseline 9m), if the muon background is too high
Aug 22, 06
Global Design Effort

18. Details of the new layout
Alcoves 4*6m, spaced at 100m for BDS equipment, PS, etc.
Passages between beamlines
9m shaft for BDS access
There is NO shaft at the end of the linac
Aug 22, 06
Global Design Effort

19. Details of the new layout
Cavern 35*20m for tune-up beam dump water cooling system
Caverns 35*20m for main beam dump water cooling system
Aug 22, 06
Global Design Effort