T. Kawamoto1 Recommendation for the New Small Wheel layout T. Kawamoto (NSW i-project leader), J. Dubbert (NSW i-technical coordinator), L. Pontecorvo (Muon PL), S. Vlachos (Muon deputy PL), NSW review panel M. Nessi, P. Farthouat, A. Romaniuk, F. Lanni, N. Konstantinidis Muon week, NSW workshop

T. Kawamoto2 Motivation for NSW : the two pillars Kill the background L1 in endcap (  =1.3 – 2.5) and reduce the rate by factor ~6 Ensure precision tracking up to the ultimate Lumi (7x10 34 ) with a comfortable safety margin On-line reconstruction of track segments, 1 mrad resolution L1MU20  distribution Rate vs R in SW necessary step for further upgrade: phase-2

T. Kawamoto3 History Many years of R&D on the possible technologies for the NSW – sMDT: 1/2 diameter of MDT tubes to gain factor 7 in rate capabilities. Proposed for tracking – sTGC: Read out strips of 3mm with a T over Thr technique to reach 100  m resolution usable also for triggering, very good rate capabilities proposed for triggering and tracking – Small gap RPC: sub ns time resolution and 300  m space resolution, rate capabilities increased by >10 with thin gap and new front end electronics, proposed for triggering – Micromegas: very good space resolution, very high rate capabilities, very promising new technology, proposed for triggering and tracking

T. Kawamoto4 History A lot of very interesting results and improvements on both new and “old” technologies has been achieved and presented in the upgrade meetings. Last year – Tatsuo Kawamoto was elected Project Leader of the new Small Wheel – to move from the R&D phase to the definition of the project – Defined the timeline for this transition: first months of – A panel was formed in summer 2011 with the mandate of helping us in defining the NSW technology. A. Romaniuk, F. Lanni, P. Farthuat, N. Kostantinidis and M. Nessi. Huge work done by the panel together with the proponents of the technologies in a very open and constructive spirit. Many Thanks from our side to them. It was a real pleasure to work with them January 2012 meeting in Le Brassus where the ideas and the questions of the panel on the different technologies were presented and a lot of discussions took place.

T. Kawamoto5 History Few weeks later we converged to two proposals, which were circulated in the community for evaluation The community at large has been asked to report their ideas on both proposals, and their willingness to participate to the NSW project regardless of the chosen scheme and their initial field of interest. – Many discussions with institute leaders and people interested in the project. – Again with very open and collaborative spirit. The community ended up split almost exactly in two, but the overwhelming majority declared that they would happily work also on their second choice. The Panel, the muon and the NSW management had a series of meetings among them, with very deep discussions on both pros and cons of the proposed solutions. Friday 16 March the NSW and the Muon management, in agreement with the Panel, decided to recommend to the community a single solution.

T. Kawamoto6 Next steps This meeting: mainly to assess the consensus of the community on the proposed solution Thursday at the Muon IB: the NSW and muon management will ask for Endorsement on this recommendation. – P.S. The Muon IB cannot decide on items that are relevant for the full collaboration, but can give endorsement to the proposal – The ATLAS CB will vote to give the final approval.

T. Kawamoto7 Two proposals Homogeneous: sTGC + Micromegas Possible full redundancy for trigger and tracking. Featuring high rate capabilities and space resolution on both detectors Split: sTGC for triggering, MM ( small R ) and sMDT ( large R ) for tracking. Featuring larger safety margins in case of problems with MM technology sTGC MM sMDT Homogeneous Split chamber segmentation in R and order along z are preliminary

T. Kawamoto8 Two proposals sTGC is used in both options for triggering and tracking – Pros: sTGC construction can start very soon, proven technology Adequate time resolution for BC identification Adequate space resolution for trigger and tracking – Cons: sTGC internal and external alignment concept has to be studied Limited number of institutes interested in the production and operation of this detector (Need to be reinforced).

T. Kawamoto9 Two proposals Why the RPC was not further considered – Main feature of RPC is the sub-ns time resolution It is clear that this can give a very large fake rate reduction We acknowledge it, but we think that the same reduction can be achieved also using other means (granularity, space resolution+ moderate time resolution) The space resolution presented was of about 300  m, not demonstrated on-line at the moment We consider it sufficient for the trigger, but has to be demonstrated on-line and moreover it is by far not sufficient to complement the tracking, sTGC on the other hand have this possibility with a moderate time resolution. The presented project is considered not very clear and advanced, we acknowledge that we received lately an addendum with clarification and new information.

T. Kawamoto10 Two proposals Homogeneous : Pros – Fully redundant: Both TGC and MM can be used in the trigger system allowing a very robust and flexible trigger even in the presence of very unexpected backgrounds or detector failures. Both detectors can be used in the tracking with adequate intrinsic space resolution. – Very robust pattern recognition and tracking with as much as 16 space points (3d) per track. – Excellent Rate Capabilities for both detectors – Very large safety margins on cavern background possible. – Very good two track separation (MM) and pattern recognition capabilities – Simpler service distribution (2 technologies) – Large community interested in development of Micromegas also for future use in ATLAS

T. Kawamoto11 Two proposals Homogeneous : Cons – Extensive R&D required for proving feasibility and industrialization of of large sized MM –  TPC operations for large angle tracks to be demonstrated, change in reconstruction method as a function of track angle. – Both internal alignment and global alignment concepts have to be developed (cf. sMDT). – Large number of channels – More “risky” solution, implying the use of new detectors within a fixed schedule (no LHC delays this time)

T. Kawamoto12 Two proposals Split : Pros – sMDT is a well proven technology, adequate for a large part of the NSW acceptance (but possible issues for unexpected background at large eta). – No more R&D required on sMDT and production can start very soon. – Alignment concept already developed for sMDT (not for MM as in the previous solution) – MM of CSC like dimension can be built very soon and the industrialization process can start sooner. Moreover if any problem in the MM construction/operation is encountered a fall back with full sMDT can be envisaged even quite late in time (Fail safe solution) – Production of sMDT ensure the formation of new experts to maintain not only the NSW but the full detector. – The sMDT offline reconstruction is almost identical to the one used now. Readiness for the first collisions in 2018 (at least for the sMDT part). – The sMDT can be used as demonstrator for the use of MDT in the trigger necessary in phase 2 on the Big Wheel and barrel.

T. Kawamoto13 Two proposals Split : Cons – Complexity in the construction and surface commissioning: 3 systems – More complex service distribution – Rim will be full of on-detector electronics – The R&D needed on some technologies is similar in the two approaches. – Different algorithms for track reconstruction as a function of the incident point in the NSW (MDT – MM).

T. Kawamoto14 Two proposals Common comments in favour of Homogeneous – Full redundancy especially for the trigger (not present in the Split solution) – Better performance in terms of resolution and rate capabilities – Simplicity in commissioning, operation, services etc. Common comments in favour of Split – Best option where the strength of each technology is used effectively. Given the short amount of time it is also the most realistic solution with the lower risk. – Potential of creating new experts for future maintenance of MDT and TGC of the full detector – Ready to reconstruct tracks (at least the sMDT part) from day 1 of LHC Response of the community

NOT Responding yet Community split in half Large majority interested in contribution to the upgrade even if their preferred solution is not chosen: about 80%

Homogeneous Solution Cost CORE cost. No overhead for manpower, R/D etc Approximate Budget based on input from proponents Common cost for F/E electronics Trigger electronics not included Rough estimation of installation etc cost Budget : KCHF – sTGC : 2300 – MM : 6000 – Common : T. Kawamoto

Split Solution Cost In addition to previous: Fixed costs kept as before Variable costs scaled to size/number of channels Rough estimate of overhead for three technologies installation Budget : KCHF – sTGC : 2300 – MM : 2800 – sMDT : 2300 – Common : T. Kawamoto The cost for the two options is ~ equal

T. Kawamoto18 The single solution to recommend We recommend to adopt the Homogeneous solution for the following main reasons: – Redundancy in both trigger and tracking, especially on trigger – Strength of the community behind Micromegas that mitigate the worries on the R&D still needed – Simpler solution in terms of number of technologies and services distribution. – Development of a new powerful technology also for other possible uses in the future of ATLAS.

T. Kawamoto19 Additional remark We consider both sMDT and mRPC to be very important technologies for further upgrade of the muon spectrometer, for examples: Inner BW region Transition region (trigger and tracking) EIL4, BIS7,8, EE, BEE Gaps of acceptance Improving the trigger p T resolution (barrel and endcap) and therefore in the strongest way to support their further development.

T. Kawamoto20 A few parameters of the homogeneous solution Number of chambers Number of layers Number of readout channels Number of trigger channels Number of fibre links K 64K(*) 800(*) M 31K 2000 sTGC MM * nr of pads * trigger signals

commissioning installation JD-nSW integration removal old nSW assembly + system tests integration and commissioning at CERN chambers / electr. construction module 0 qualified in beams Module 0 construction approval/organize resources TDR Design & gen R&D support structure construction Time line An idea to see if all fit T. Kawamoto

T. Kawamoto22 Critical milestones Form a simulation group by mid Construction of a few MM chambers (4 planes), of max size achievable at the moment, in next 3 months, and tested at H6. Production and test of a full size prototype for both technologies by beg Qualification of the FE electronics (BNL chip) by fall Demonstration of the MM spatial resolution with mTPC by fall Demonstrator of the trigger concept by mid Results on ageing and performance under irradiation by end Test of triggering capability under irradiation by end Precision of mechanical assembly by mid Precision of the mechanical assembly (including strips precision and internal alignment) : a system test, by mid Qualification of components prior to start of production. Draft

T. Kawamoto23 How to organize the project Consortia: – Detector construction and integration Sites, groups – Alignment (work together with detector mechanical design) – Production Quality assurance – Detector Control system – System integration (mechanics, services, cooling, …) – Front end electronics – Trigger front end electronics – Trigger backend electronics – Readout system – Software Simulation Reconstruction Starting the even more difficult part

Consortia concept (first idea) (chambers technology is not the end of the story) Chambers technologis Mechanical structure, alignment, … Back-end, RODs, Online software, controls, services, power LVL1 Trigger Electronics Front-end electronics T. Kawamoto

T. Kawamoto25 Next steps Collaboration formation iMoU TDR Real work

T. Kawamoto26 Back up

T. Kawamoto27 LHC and ATLAS upgrade ∫ L dt Year phase-0 phase-1 phase /142018~ TeV→14 TeV → 2x10 33 cm -2 s -1 → 1x10 34 cm -2 s -1 1x10 34 → ~2x10 34 cm -2 s -1 Now ~10 fb -1 ~50 fb -1 ~300 fb fb -1 → 5x10 34 cm -2 s -1 luminosity leveling Possible upgrade timeline new shielding winter elevator hole chambers trigger in barrel feet region New small wheel And more Integrating small wheel TGC in Endcap L1 : update SL programing

T. Kawamoto28 Phase-1 upgrade : the new small wheel Protons : tracks and their birth position FLUGG simulation, no cut on p

T. Kawamoto29 Phase-1 upgrade : the new small wheel coil cryostat Unshielded beam pipe

T. Kawamoto30 K. Nagano

T. Kawamoto31 NSW spec is designed for further upgrade NSW primary goal : to remove fakes. Designed also for improving p T of L1 size of luminous region 1-2 mrad multiple scattering in the calorimeter 2-3 mrad multiple scattering in the EC toroid 1 mrad angular resolution of BW 3 mrad measure and correct with NSW: need 1 mrad resolution upgrade of BW (phase-2) nominal threshold p T after fake removal with NSW

T. Kawamoto32 Trigger and tracking improved by NSW What about other region?

T. Kawamoto33 What about other region? Not covered by NSW. Something else is needed.

T. Kawamoto34 What about other region? Implementation into the trigger is planed at phase-0 upgrade (201 ３ /2014) Find wire/strip hits in a same chamber Geometrical matching between BW RoI and TGC-inner. Emulation of trigger with TGC-Inner Reduction for “L1 MU11” 81.0% Eff. for offline Pt>MU % TGC-EI: 1.02<|η|<1.24 TGC-FI: 1.23<|η|<1.88 η coverage of TGC-inner Something that can be done before NSW using existing detectors TGC (doublets) on EI (small wheel, EIL4), currently not used for L1

T. Kawamoto35

T. Kawamoto36 Phase-2 ideas and more Barrel L1 upgrade (using MDT) : better p T resolution Further L1 upgrade in endcap (using also MDT to improve big wheel): better p T New trigger chambers for barrel-endcap overlap region. Profiting from longer L1 latency