1. Consolidation and Upgrade of the LHC Experimental Vacuum Sectors
Ray VENESS / TE-VSC

2. Contents LHC Experimental Beampipes (LEB) working group
Consolidation and upgrade project
Planned changes to LHC Experimental Vacuum
Changes in the 2012 shutdown
Changes for the ~2015 shutdown
Review of the central beampipe radius
Changes for a replacement inner triplet
Conclusions
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

3. Organisation of the Beampipe Upgrade Project
LEB (LHC Experimental Beampipes) working group
Re-started in Jan ’09 following encouragement from LHCC and CARE Workshop
Mandate to “Define, set priorities and follow-up the activities for the consolidation and upgrade (phase I and II) of the experimental vacuum sectors in the LHC”
Not looking specifically at operation issues for the ‘baseline’ design
Members proposed from all 5 experiments, plus machine groups and machine coordination
INDICO site:
LEB action plan
Step 1: Prepare list of priorities, with budgets and resources [done]
Step 2: Agree baseline diameter for upgrade central pipes [done]
Common request from ATLAS and CMS
Step 3: Agree layouts for 1st generation upgrades (ATLAS and CMS) [in progress]
Step 4: Follow-up R&D and design of upgrades [in progress]
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

4. Project Overview Timescale Volume of work Project resources
Covers period
Includes preparatory work for longer-term activities
Volume of work
3 new beryllium chambers
11 other new vacuum chambers
8 other vacuum technology developments
Development, design, construction, installation, commissioning
Project resources
~29 FTE staff (~5 people average full-time)
A staff engineer and technician (10 FTE) are currently being recruited for this activity
~7 FTE visitors
1 fellow and 1 technical student selected
~9.5 MCHF, of which ~6.5 MCHF is installed hardware
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

5. 2012 Shutdown: ATLAS 4 new vacuum chambers
Half-length of the ATLAS beam vacuum sector
4 new vacuum chambers
Same geometry, less material (Z)
Replace stainless steel with aluminium (baseline)
ALARA during interventions
Detector background
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

6. 2012 Shutdown: LHCb 1 new chamber and 2 new support systems
Cross-section of LHCb experiment
1 new chamber and 2 new support systems
Install a replacement UX85/3 conical beryllium chamber
No change to layout or material
Install and position new ‘spider’ supports for the UX85/2 and UX85/3 chambers
Re-optimised with material changed from aluminium to beryllium
View inside magnet showing chambers and spider supports
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

7. 2015 Shutdown: ATLAS and CMS
ATLAS and CMS consolidate PIXEL detectors
Add another ‘layer’ of pixel
IBL in ATLAS
4-layer PIXEL in CMS
Make room for the detector by reducing the central beampipe diameter from 58 to 50
Smaller beam aperture at IP
Changes to layouts
Design and production of 2 new beryllium chambers and support systems
Retro-fit inside existing ATLAS detector
Replace detector in CMS
Installation of CMS beryllium
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness
ATLAS beryllium pipe seen through the PIXEL

8. Outcome of LEB review of central beampipe radius
Current Design
(mm)
Phase I (proposed)
Beam aperture (10σ) 14
Alignment
2.6
Construction and deflection
Stability during run, and between alignments
9.8
5.8
Physical radius of pipe 29 25
See comments on the next slide!
ATLAS Upgrade - 9 VI 09
Beam Vacuum- R.Veness

9. Central beampipe radius: Issues and Questions
‘Baseline’ established 28/5/09 in the LEB-WG
Considering: Phase I upgrade machine, 14 TeV collisions, high-luminosity (low-β) optics, in the region ± 2 m from the IP
25 mm beampipe radius is compatible with ‘upgrade’ aperture and mechanics
Aperture for the ‘baseline’ optics and beampipe was confirmed in a LEB meeting in Sept ‘09
There are some issues
Very high-β operation is not compatible with 25 mm radius for currently achievable emmitances
Radii of forward chambers (eg, CT2) must be re-evaluated for Phase I upgrade
A number of open questions remain to validate this number
Machine protection (larger TAS, smaller diameter central pipe)
Machine-induced background (see example for CMS)
Beam impedance requirements (smaller diameter central pipe)
Re-evaluation of vacuum performance (smaller diameter, less conductance)
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

10. From a talk by R.Horisberger/PSI to CMS beampipe upgrade meeting, April 2010
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

11. From a talk by Bendavid, Marinelli, Hanson, Liu
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

12. Background in the CMS Central Pipe
Beryllium
Stainless steel
How long should the beryllium section be?
Smaller diameter beampipe with PIXELS closer to the IP: More background from the machine?
This could be worse with a larger diameter TAS
Should the new beryllium section be extended into the larger diameter cone?
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

13. LHC Triplet Upgrade
This zone is fully integrated into the experimental cavern (eg. CMS)
Interface zone between Q1 and the high-luminosity experiments (ATLAS, CMS)
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14. LHC Triplet Upgrade
All the vacuum components over this length in ATLAS and CMS will need to be re-designed and replaced
Remote flange
TAS chamber
BPMSW
VAX
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

15. CMS: CT2 chamber CMS CT2 chamber
Half-length of the CMS beam vacuum sector
CMS CT2 chamber
50mm diameter chamber for TOTEM/T2 and CASTOR detectors
Smallest diameter in the LHC experimental sectors
Some initial alignment and stability problems – supported from the HF platform
Planned for replacement when T2 and castor are removed
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness

16. Conclusions ATLAS and LHCb: ‘Low-Z’ consolidation in 2012
Change chamber and support materials to reduce background from the interactions and facilitate access (in ATLAS)
No changes to the geometry currently planned
ATLAS and CMS: New PIXEL layers in ~2015
Change central beryllium beampipes for smaller diameter versions
Longer-term changes
A new triplet will mean a larger diameter TAS and a complete re-design of the forward regions of ATLAS and CMS
ALICE would like to replace central beryllium pipe with a smaller diameter
but do not consider 50 mm diameter small enough to warrant a change
Wait and see what can be achieved when we understand the machine better – this is starting to happen
Links between LBS and LEB
Changes in layouts will require an understanding of the impact of background
Issues are experiment-dependant, and requests should come from the experiment
We need to keep each other updated on the progress and ensure we use the same models
LBS group 14 VI 10
LHC Exp.Vac. - R.Veness