A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Phase II Collimators: design status, options and future outlook LHC Collimation Phase II 10 th Design Meeting 19 th September, 2008 Alessandro Bertarelli Alessandro Dallocchio

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 …excerpts from last LHC MAC (R. Assmann talk)… Overall time plan Scheduling:  Define general directions until July 08.  Prepare conceptual design until October 08.  Discuss conceptual design and organize project details in November 08.  Testing of hardware in 2009/10 (lab and beam tests).  Time plan will be (is already?) affected by start of LHC beam operation (highest priority to make phase 1 collimation system work). :.  Important milestone: Review of conceptual design with parallel development paths in late autumn 2008.

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/ Functional Specification   Phase II present boundary conditions:   New Secondary collimators (TCSM) to be placed immediately downstream of Phase I Secondary collimators (TCSG)   Stands, electric and water connections already available   Same interfaces as Phase I   Affecting only IP 3 and IP7 (~ 30 units), no modifications to SC areas.   Additional collimators and modifications in SC areas may be required to overcome intensity limitations.   Phase II goals (our interpretation):   Gain factor ≥10 in cleaning efficiency.   Gain factor ≥10 in impedance.   Gain factor ≥10 in set-up time (and accuracy?).   Radiation hardness and easy handling.   Improved geometrical stability (in operating conditions) 20  m   Sufficient robustness (like Phase I?). Minimal system

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Functional Specification   Modular concept to fit in alternative jaw materials (All-metal, Metal- diamond, Ceramics-metal, Thin foil etc.) and concepts (alternative cooling systems)   Increase geometrical stability and precision (e.g. jaw flatness).   Increase cooling capacity.   Capitalize Phase I experience to improve existing design (e.g. new moving tables)   Collaboration with external partners to identify, develop and test novel advanced materials (EPFL, Plansee, Politecnico di Torino, Kurchatov, BNL)   Possibility to embed in jaw design Beam diagnostic devices (BPMs, BLM(?) …) Design Guidelines as we see them …

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Jaw+cooling system Fine adjustment System Rigid Support (back- stiffener) Baseline of the design geometrical stability Preliminary design is based on the concept of a back stiffener remaining at uniform temperature and ensuring geometrical stability of the jaw beam. Back stiffener Metal support (cooler) Jaw (monolithic case shown)

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Main components of Phase II jaw assembly:  Back-stiffener  Fine adjustment system  Equipped Jaw  Collimation Jaw  Jaw Cooling system  Beam diagnostics devices  RF system Baseline of the design

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Stiffener material requirements: Minimise thermal bending Low CTE High thermal conductivity Minimise deflection provoked by the force in the adjustable system High Young’s modulus MOLYBDENUM Molybdenum Back-stiffener Stiffener plates (~1.1 m long; up to 20 mm thick) Fine adjustable system support fastened to plates Stiffener ribs fastened to plates The design is already at an advanced stage, Mo seems to be the best candidate. PLANSEE confirmed the feasibility of this component (10-12 weeks to produce a prototype).

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Fine adjustment system Fine adjustment system (overall deflection controlled) Cooling pipes on the stiffener plates (geometrical stability) …feasibility of Mo screws confirmed by PLANSEE…

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Jaw and cooler: Design options …depending on RF and cleaning efficiency specifications…

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Collimation jaw  Monolithic metallic jaw (Glidcop) – Studied.  Monolithic Cu-diamond + Cu coating – Being studied  Plansee available for advanced co-design (investment necessary?)  Monolithic Al-diamond + Al coating – Being studied  Collaboration with EPFL already launched: Development of Al-CD jaw + Al coating + Al-CD cooler with Zr or Inox pipes. Mock-up possibly available within few weeks.  Ceramic tiles on metal support – Being studied  Ongoing research of suitable ceramic materials following preliminary spec. by RF experts (SiC is expected to be a good candidate)  Thin metal foil on low conducting support – To be studied  Preliminary RF studies show that no major difference exists between monolithic metal jaw and thin metal foil bonded on low conducting support. Possible advantages in terms of robustness RF studies have not yet clarified the choice between high/low electrical conductivity materials. Options for high or medium density materials (collimation efficiency) still open. Possible design options:

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Collimation jaw Metallic support Ceramic tiles Ceramic absorber with metallic (conductor) support…

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Jaw Cooler and pipes Increased energy deposition (high / medium density jaw materials) requires much higher cooling capacity with respect to Phase I (factor ~5) Design alternatives:  Machined circuit with brazed covers (Glidcop or Cu-Diamond) – studied.  High cooling capacity, relatively easy production. Remark  Not in line with UHV recommendations → …(Remark: Plansee developed and qualified a very similar solution for ITER project in a similar environment)  Continuous bent pipes back-casted in metal diamond – being studied  Plansee available for co-development using Ta or Nb pipes in Cu-CD (investment required?)  EPFL also working on this option using Zr or Inox pipes in Al-CD  Machined circuit sealed during casting – To be studied  Continuous bent pipes brazed to jaw cooler – Derived from Phase I solution

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/ Jaw Cooler and pipes Cooling pipes back- casted in metal support Cooling circuit machined in metal support with brazed covers

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/ BPM integration Integration of BPMs into the jaw assembly gives a clear advantage for set-up time BPM pick-ups BPM cables and electrical connections

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/ RF contacts RF stability provided by ferrite blocks and metallic rails (no sliding contacts) Ferrite blocks placed all along the jaw Ferrite blocks ensure beam stability without sliding contact Metallic rail

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Fine adjustable system: preliminary thermo-mechanical analysis for 8e10 p/s scenario confirm the validity of the design principle (back stiffener + collimation jaw). Max deflection:106  m Temperature is underestimated due to unrealistic boundary conditions!!! Max ΔT : ~30  C Thermo-mechanical analysis Mo back-stiffener Cu cooling system Cu jaw Max deflection:80  m

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 Future Outlook 1. Back stiffener / central adjustment principle seems so far a viable solution  We continue on this path 2. RF studies have not yet allowed the choice between high/low electrical conductivity materials  keep all material options open (metal, ceramic, thin foil). 3. Effects of material density on global collimation efficiency not yet clarified  options for high (Cu) or medium (3÷5 kg/dm 3 ) density materials still open. 4. Cooling system: we prefer the machined solution (more efficient and feasible); back-casted option should be kept only if a clear veto on machined solution is emitted. Keeping options 2, 3 and 4 open has a cost in terms of required design manpower. 5. BPM pick-ups embedded in jaw assembly seem attainable; BLM to be evaluated only if compact enough to be hosted in collimator jaw  reduction in jaw effective length 6. Jaw robustness for the moment relies on +/-10 mm external tank translation. 7. Increase reliability of actuation system by new moving table design. 8. Continue/strengthen collaboration with EPFL and Plansee. Our view on future activities …

A. Bertarelli – A. DallocchioLHC Collimation Phase II – Design Meeting – 19/09/2008 In order to meet the challenging objectives and deadlines of this project the following points should be rapidly addressed:  Tracking studies followed by Fluka analyses for all possible scenarios (nominal and accident), designs and jaw materials:  Cu/CD + Cu coating  Al/CD + Al coating  Ceramic tiles (+ Thin foil)  Decision on cooling circuit solution (involving AT-VAC and SC-RP)  Gear up in RF studies to rank different options (unfortunately E. Métral team has lost a ad-hoc PhD candidate).  Validate BPMs baseline to go ahead with Jaw design. Evaluate BPM possibilities  Consolidate contacts with interested institutes (Kurchatov, BNL) for irradiation studies on advanced materials. Future Outlook To-do list … Most urgent