A common vision of a new Tracker is now essential It may not be final but a focus for shared efforts is now vital

Transcription

1 CMS Tracker Phase II Upgrade planning A common vision of a new Tracker is now essential It may not be final but a focus for shared efforts is now vital G Hall

2 New injectors + IR upgrade phase 2 Linac4 + IR Early upgrade operation phase 1 Collimation phase 2 Geoff Hall TK Upgrade Jan

3 Phase I upgrade involves only the pixel system unless we discover that FED improvement is required The design for easy pixel replacement was very wise we can replace whenever we are ready to do so Possible scenario andtimely R&Dshould evolve it gracefully towards Phase II Phase II upgrade: design pixel system with 4 barrel layers and expanded endcap Phase I should fix mechanical envelope and services study PT (stacked) layers to contribute to trigger (and alternatives) design outer tracker to match cost, power and performance needs However, the official Phase II SLHC schedule is not so tolerant a careful assessment of timescales and costs is required very soon Geoff Hall TK Upgrade Jan

4 Proposed dates for documents Concept mid 2008 LOI/TP mid 2009 TDR Early 2010 Phase I Upgrades Strawman TP/LOI TDR Phase 2 Upgrades Mid 2009 Mid Normally, for a TDR, engineering studies should be sufficiently advanced usually evidence fromprototypingthatconcepts that areviable beam tests of trigger modules probably essential Geoff Hall TK Upgrade Jan

5 Time constraints 18 months to LoI (must report more progress than simulated layout) ~3 years ( ) for R&D prior to TDR TDR preparation likely to need ~6months Review Project plan (outline sketch not revisited since 2007) ensure to examine coupling between tasks which include Sensors and assembly technology(/ies) Electronics FE, trigger, control, monitoring, off detector Module development cooling, interconnects, mechanics Power system completely new system Links electrical and optical with concentrator ASICs Phase II pixel system Costing provisional quotes essential by TDR stage Geoff Hall TK Upgrade Jan

6 Physics requirements Many arguments for upgrade which so far provide modest guidance, eg SM Higgs improve statistics to investigate couplings SUSY measure more exclusive final states rare top decays requiring goodb tagging new gauge bosons perhaps not much demand on tracker? The general request is for improved tracking performance pileup issues in dense environment good vertex resolution (~400 vertices in 20cm 0.5mm spacing) but tracking performance cannot be sacrificed for other motives Within a few years we will know more and may need to react design should be flexible and adaptable tolerant tof variations, iti eg occupancy, specific physics channels Geoff Hall TK Upgrade Jan

7 Negative How ambitious do we wish to be? resources have so far been very limited compared to the project scope CMS continues to demand priority and all resources seem stretched the overall economic situation appears uncertain downscoping is painful and demoralising Positive we have achieved much in the past years therefore we should be aggressive in future technology progress will help us (and is essential to succeed!) a recession can make technology access easier Nevertheless, it seems prudent to develop a system which matches likely resources further assessment is needed dd Geoff Hall TK Upgrade Jan

8 EoI estimated 30MCHF (pixels) + 90MCHF (outer tracker) assumed to include triggering functions but R&D costs are extra Budget Not so different from present system, yet far more demanding R&D funding is not yet in place, although h beginning i to flow we have not made serious estimates of R&D costs some important items are very expensive, such as ASIC engineering effort and funding are tightly linked We must work quickly with Resource Manager to improve estimatesandestablish and establish likelyfunding some agencies need extra arguments and possibly documentation to release funds Geoff Hall TK Upgrade Jan

9 What is maximum tolerable power? Power Task Force will report recommend DC DC converters ~12V Present current is considered to be maximal ~15kA Upper limit ~180kW including all losses within the Tracker over simple calculation? What is a realistic target for a new cooling system? What external power source can be afforded/provided? present Si Tracker 35kW requires 300kVA supply Do we want a.../45/90/180 kw Tracker? Power up to now we have usually assumed a direct relationship between material budget and power what does physics require? It is not easy to estimate electronic power for new functions Geoff Hall TK Upgrade Jan

10 The track trigger challenge What are minimum track trigger requirements? (My synthesis) single electron tracker point validating a calorimeter projection single muon a tracker point in a limited η φ window jets information on proximity/local density of high p T hits? photon triggers?? separation of primary vertices full η coverage (±2.5) It is not easy for the trigger to state their hirequirements in terms the tracker can interpret directly it would be natural for the trigger to evaluate a concept providing reasonable minimal information, not maximal we have proposed two layers, at radii covering full η range It is essential to know how this performs before going to more ambitious layouts Geoff Hall Liverpool Jan

11 Trigger primitive generation After several years, only a few ideas for implementation both have significant weaknesses which need R&D ti trigger layers are inevitably it much more power hungry (=material) Cluster width sensitive to sensor thickness, rejection adequate?, η coverage (since outer tracker) with no solution so far for endcaps Stacked layers (doublets spaced 1 2mm radially) original simulations based on tiny pixels and no multiple scattering but full simulations of coarser pixel layers support concept applying correlation logic still raises serious practical problems the problem of inter layer communication is unproven and will cost power, which may be a show stopper NB monolithic detectors are equally subject to this problem From Tracker perspective, it is crucial to demonstrate modules to provide primitives before worrying about perfect triggering most likely a balance between tracking and triggering must be adopted Geoff Hall TK Upgrade Jan

12 Technologies Generic or common R&D projects look likely to develop some components (especially link system elements) our influence over specifications depends on our ability to specify our requirements (soon) ASICprocesses willevolve further during project lifetime no major (tracker) designs yet in 130nm but expertise exists a simple outer readout chip might be delivered in ~ 1 year and then can be evaluated, with modules & sensors vital aid and learning engineers more cautious about 90nm expensive, substantial learning, much more complex design rules & tools sharing costs may be essential number of systems to be developed must be limited outer tracker and trigger layers = 2 (but could be larger) our engineering resources are modest and many ASICs needed Geoff Hall TK Upgrade Jan

13 The role of monolithic detectors Can they be major contributors to new Tracker? Pros a single concept providing tracking and trigger functions would be easier to build a common effort around Cons the technology is unproven and unlikely to mature rapidly there are many unknowns which will require time and effort the R&D cost may be high, since deep sub micron processes If good progress could be shown in ~2 years, it will not be too lateto to review the trackerdesign significant power or functional advantages would be a strong motivation to adopt a new technology, even if late Geoff Hall TK Upgrade Jan

14 Simplicity was a big factor in our previous success the future is more complex Past vs future There were impressive achievements, but modest novelty sensors, ASICs, assembly technology, cooling, engineering, used standard or proven technologies (links were main exception) Previous upgrade projects have not usually been on this scale improvements, using technologies which were mastered earlier Contingency is required in setting targets power and cost, like entropy, seem to go in one direction correcting issues alwaysadds adds time, usually cost andpower New issues will arise or old ones grow in importance operating temperature, alignment, deep evaluation of new functions, all kinds of testing, extraction and installation in irradiated region, Geoff Hall TK Upgrade Jan

15 Small steps, in the right order Geoff Hall TK Upgrade Jan