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

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

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: http://indico.cern.ch/categoryDisplay.py?categId=2261 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

Project Overview Timescale Volume of work Project resources Covers period 2010-2015 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

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

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

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

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

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 http://indico.cern.ch/getFile.py/access?contribId=0&resId=1&materialId=slides&confId=67351 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

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

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

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

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) LBS group 14 VI 10 LHC Exp.Vac. - R.Veness

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

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

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