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ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 1 Results from Studies for a Tracking Trigger for CMS at SLHC Overview of this.

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Presentation on theme: "ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 1 Results from Studies for a Tracking Trigger for CMS at SLHC Overview of this."— Presentation transcript:

1 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 1 Results from Studies for a Tracking Trigger for CMS at SLHC Overview of this talk: Trigger Goals at SLHC Expected rates and occupancies at SLHC What do we know so far from LHC studies Proposals for Tracking Trigger

2 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 2 Minimum Bias Events, a Reminder SLHC (10 35 ; 80 MHz): 110 (less likely now) SLHC (10 35 ; 40 MHz): 220 SLHC (10 35 ; 20 MHz): mb deep inelastic component

3 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 3 Triggering at the SLHC with CMS Luminosity will go up by ~ factor of 10 The clock will be 20 or 40 Mhz The FLT latency will be 6.4  sec (true for 40 MHz) Maintain L1-Output at 100 KHz Hence, given that the backgrounds will go up by a factor of 10 (40 MHz) or even 20 (20 MHz) one needs to cut the rate at FLT. The obvious thing to do is to use tracking information in producing the L1 decision.

4 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 4 SLHC Triggers Assuming that one decides to include the tracking information in the L1-Accept decision, a look at the HLT algorithms prepared for LHC shows what needs to be done: Electron Triggers Tau Triggers Muon Triggers Jets triggers ?

5 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 5 SLHC Rates Rates calculated using CMS software (ORCA) at 80 MHz  double them for 40 MHz. No charge sharing has been included. Hence, another factor of at least two to make them realistic.  10 Gb/s/cm 2  100 Tb/s C.Foudas, A. Rose, J. Jones, G. Hall, LECC2005, Heidelberg

6 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 6 Check against older CMS results The simulation results are consistent with early CMS results from the Tracker TDR. Later will give the result which included all other effects such as charge sharing A. Rose MSci thesis Imperial 2004

7 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 7 Electron Triggers Gain a factor of 10 by requiring a hit in the inner tracker Another factor of 3 from using the outer tracker. Inner Tracker is absolutely essential for a tracking trigger. G. Daskalakis CMS Note

8 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 8 Tau Triggers Tau Triggers also require isolated high p t stubs in the inner tracker to detect hadronic decays of taus (65%). The QCD jet efficiency can be reduced by a factor of 10 while tau jet efficiency rises to 75 %. Efficiency for QCD events

9 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 9 Muon Triggers Large Factors to be gained also for muons. Outer tracker subs may be important here.

10 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 10 Tracking Trigger Challenges Need to design a system which finds high Pt stubs and places them in coincidence with L1-Cal and L1- Muon triggers. Raw rate from the detector needs to be reduced otherwise power and large number of electronic components (useful for trigger but inactive material for others) will make the idea prohibitive. Some kind of a hit correlation finder, correlator, is needed since to reduce the number of combinatorics before one attempts to find tracks and correlate with calorimeter L1 trigger objects.

11 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 11 The Stacked Tracker idea Have a stacked pixel detector where the two layers have a radius difference of few mm. Require coincidences between the pixels of the two layers to select high Pt stubs  Momentum cut. Removes all the low pt particles. See: J. Jones et al., A Pixel Detector for L1 Triggering at SLHC, LECC 2005 α

12 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 12

13 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 13 Component Output bandwidth per unit Rate Reduction Number of units per upstream component Total number of units Aggregate output bandwidth Sensor (20cm 2 ) 10Gb/ s cm 2 N/A~0.4~1600~140Tb/s Hit Correlator (5 per 20cm 2 stack) ~1.6Gb/sX50~2~2000~3Tb/s Opto TX and SERDES ~3.2Gb/sN/A12~1000~3Tb/s 12xSFP to SNAP12 Cable ~40Gb/sN/A5~90~3Tb/s Regional Track Generator ~50Gb/sX4~3~18~1Tb/s Global Track Generator ~4Gb/sX40~6 ~25Gb/s Global Track Sorter ~10- 20Gb/s X2?N/A1~10-20Gb/s Bandwidth Requirements

14 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 14 Two Stacked Detectors By introducing a second double stacked detector one can measure angles and transverse energy of tracks at reasonable resolution. See: J. Jones, A. Rose et al., Stacked Tracking with CMS at SLHC LECC 2006, Valencia.

15 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 15

16 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 16 Rapidity and Pt resolution  = –  P T / P T = 10 -2

17 ATLAS-CMS SLHC Workshop, 20/3/07 Costas Foudas, Imperial College London 17 Summary and Outlook Electron Trigger Studies: A. Rose Detector Designs/ideas: J. Jones Need urgently to look into muon, tau and other triggers. Some Algorithm development on FPGA (Virtex-II Pro) by IC MSci Students already done. Intend to study more algorithm developments using the V5 Card (see M. Stettler’s talk and M-TCA backplane) A number of CMS collaborators have signed up for the V5 project (Maryland, Imperial, Wisconsin) with Bristol playing a significant role in Simulations and algorithm development. Need urgently collaborators for the most important part of this namely the detector part (Detector design, ASIC- Correlator and Electronics)


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