Online tracking in Atlas: the Fast Track project

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On-line tracking in Atlas the Fast Track project

• Mario Campanelli
• Geneva Atlas meeting
• 8/12/2004

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Introduction the SVT

• It is hard to overestimate the importance of the
  SVT on the physics output of CDF II.
• The whole new area of hadronic b decays is now
  open, as well as searches involving b final
  states

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SVT scheme
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Is something similar possible at the LHC?

• the same philosophy early rejection of
  non-interesting events ? larger L1 rate for the
  same deadtime ? lower thresholds
• Goal to have a ROB with reconstructed tracks
  near the beginning of level-2 processing

• Technique process all possible track roads in
  parallel at the rate at which the silicon data
  comes out of the RODs.
• By the time the raw Inner Detector data is in
  the ROBs, all track candidates have already been
  found!

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Very low impact on DAQ
Ev/sec 50100 kHz
FE
FE
high-quality tracks Ptgt1 GeV
No change to LVL2
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• Find low resolution track candidates called
  roads. Solve most of the combinatorial problem.

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SVTs AMChip

• Dedicated device with
• maximum parallelism
• Store all patterns corresponding
• to interesting tracks
• Road search happens during
• detector readout
• How to send all hits to the AM?

• Design has 50M patterns (c.f. 32K in CDF)

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AM input bandwidth 40 MHz cluster/bus AM input
buses 6
ATLAS-TDR-11
2 FTK processors working in parallel for the
whole PixSi tracker More processors as a backup
option
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Triggers w/o and with FTK
Scenario L 2 x 1033 deferral
F. Gianotti, LHCC, 01/07/2002 CMS TDR 6
ATLAS
ATL-COM-DAQ-2002-022
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proposed RD program

• Soon in order to have the FTK in the future the
  
• only short term issue is the availability
• of the dual output HOLA. (also useful
• for diagnostic and commissioning)
• Alternative use optical splitters
• 2008 _at_ very low luminosity
• minimal RD FTK system
• very cheap using low density CDF
  AMChip
• (barrel only 40 boards)
• 2009 ? increase the RD system to include disks
• new AMChip for 21033 lumi
• (barreldisks 75 boards)
• 2011 ? upgrade for high lum.

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FTK collaboration and arguments
Start at Pisa in 1999 INFN, Dip. Fisica, Dip.
Ing. Informatica, SNS - Pisa A. Annovi, R.
Carosi, M. DellOrso, P. Giannetti, G.
Iannaccone, G. Punzi Joined in 2002 INFN, Dip.
Fisica, Dip. Ing. Informatica, SNS - Pisa P.
Catastini, V. Cavasinni, V. Flaminio, T. Del
Prete, C. Roda, G. Usai, I. Vivarelli INFN, Dip.
Fisica Roma S. Giagu, M. Rescigno, L.
Zanello University of Chicago M.
Shochet Interested to join University of Geneva
X. Wu Argonne National Laboratory J.
Proudfoot Berkeley National Laboratory I.
Hinchliffe Co-operating on software
algorithms INFN-Dip. Fisica - Genova F.
Parodi Co-operating on standard cell chip Dip.
Fisica - Ferrara R. Tripiccione

• From Mel Shochet
• US most I have spoken with trigger is ATLAS
  weak spot
• CERN
• TDAQ focused on their immediate tasks, which
  are significant
• Physics leaders are very supportive
• on the generic arguments as well as specific
  channels
• Fabiola Gianotti
• Unlikely to find single channel that is
  accessible only with FTK
• If find improvement in a number of channels, that
  is sufficient. Then the generic argument makes
  the case.
• Giacomo Polesello
• If Z-gtbb can be done, that would be
  enough.

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To-do list for physics case (Nov 2004)