1 / 33

The CDF Silicon Vertex Trigger

The CDF Silicon Vertex Trigger. Vertex 2002 Luciano Ristori Istituto Nazionale di Fisica Nucleare Pisa – Italy. SVT. SVT. The Silicon Vertex Trigger was designed and built for the CDF collaboration by people from the following institutions:. INFN – Pisa INFN – Trieste

abiola
Download Presentation

The CDF Silicon Vertex Trigger

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The CDF Silicon Vertex Trigger Vertex 2002 Luciano Ristori Istituto Nazionale di Fisica Nucleare Pisa – Italy SVT Luciano Ristori - Vertex2002_7Nov02.ppt

  2. SVT The Silicon Vertex Trigger was designed and built for the CDF collaboration by people from the following institutions: • INFN – Pisa • INFN – Trieste • University of Chicago • Université de Genève Luciano Ristori - Vertex2002_7Nov02.ppt

  3. CDF DETECTOR Luciano Ristori - Vertex2002_7Nov02.ppt

  4. CDF r-z view Luciano Ristori - Vertex2002_7Nov02.ppt

  5. 10.6 cm 2.5 cm 90 cm SVX II Luciano Ristori - Vertex2002_7Nov02.ppt

  6. Why and how? • Trigger on B hadronic decays • B physics studies, eg. CP violation in B decays, Bs mixing • new particle searches, eg. Higgs, Supersymmetry • A b-trigger is particularly important at hadron colliders • large B production cross section for B physics • high energy available to produce new particles decaying to b quarks • overwhelming QCD background • need to improve S/B at trigger level • Detect large impact parameter tracks from B decays using the fact that (B)1.5 ps Technical challenge! secondary vertex primary vertex Luciano Ristori - Vertex2002_7Nov02.ppt

  7. SVT: Silicon Vertex Trigger Inputs: • L1 tracks from XFT(, pT) • digitized pulse heights from SVX II Functionalities: • hit cluster finding • pattern recognition • track fitting Outputs: • reconstructed tracks (d, , pT) Luciano Ristori - Vertex2002_7Nov02.ppt

  8. Central Tracker (Pt,f) EM + HAD/EM + Track EM+HAD (Jet) Muon + Track Missing ET, S ET Si Secondary vertex EM shower max, ISO Jet Clustering Multi object triggers Farm of ~200 PC’s running fast versions of Offline Code  more sophisticated selections Triggering in Run 2 45 kHz 300Hz 60 Hz ~20MB/s Luciano Ristori - Vertex2002_7Nov02.ppt

  9. detector elements MUON CAL COT SVX CES MUON PRIM. XCES XFT XTRP L1 CAL L1 TRACK L1 MUON GLOBAL L1 SVT L2 CAL GLOBAL LEVEL 2 TSI/CLK CDF Run II trigger architecture • DØ results • Tracking system • central outer tracking (COT) • silicon tracking (SVX II & ISL) • three-level trigger • L1: 5.5 s pipeline • XFT: L1 2D COT track • L2: 20 s processing time • two stages of 10 s • SVT at stage 1 of L2 • SVX II readout • hit cluster finding • pattern recognition • track fitting Luciano Ristori - Vertex2002_7Nov02.ppt

  10. Finding tracks in the silicon Luciano Ristori - Vertex2002_7Nov02.ppt

  11. 5 4 3 2 1 Instead of looking for hit combinations such that f(x1,x2,x3,…) = 0 • Build a database with all patterns corresponding to “good” tracks • Compare hits in each event with all patterns to find track candidates Building the “Pattern Bank” In this example: Straight lines, 5 layers, 12 bins/layer Total number of patterns ~ (12)2*(5-1) = 576 Luciano Ristori - Vertex2002_7Nov02.ppt

  12. AB<6:0>( R/W MODE) SELP<2:0> ADDRESS DECODER SELECT PLANE DECODER pattern 0 pattern 1 pattern 127 layer0 12 bits word 12 bits compar. HIT BIT HIT BIT HIT BIT 12 bits word 12 bits compar. 12 bits word 12 bits compar. layer1 DB<11:0> layer2 DATA BUS MULTIPLEXER layer3 layer4 layer5 COUNT HIT COUNTER OPC<3:0> SHIFT ENP* CONTROL MATCH BIT SEL* CLKB ADDRESS ENCODER CLKA AB<6:0>(OUTPUT MODE) OR* AM chip internal structure Luciano Ristori - Vertex2002_7Nov02.ppt

  13. AMchip Luciano Ristori - Vertex2002_7Nov02.ppt

  14. Amplug: mezzanine board Luciano Ristori - Vertex2002_7Nov02.ppt

  15. AM Board 128 Amchips x 128 patterns each = 16K pattern board x16 VME AMbus Luciano Ristori - Vertex2002_7Nov02.ppt

  16. SVT basic architecture • Pattern recognition and track fitting done separately and pipelined • Pattern recognition with Associative Memory (AM) • highly parallel algorithm • using coarser resolution to reduce memory size Hits Associative Memory Hits Hit Buffer Roads Track Fitter Roads + hits Tracks (d, pT, ) • Fast track fitting with linear approximation • using full resolution of the silicon vertex detector Luciano Ristori - Vertex2002_7Nov02.ppt

  17. D xi From non-linear to linear constraints Non-linear geometrical constraint for a circle: F(x1 , x2 , x3 , …) = 0 But for sufficiently small displacements: F(x1 , x2 , x3 , …) ~ a0 +a1Dx1 + a2Dx2 + a3Dx3 + … = 0 with constant ai (first order expansion of F) Luciano Ristori - Vertex2002_7Nov02.ppt

  18. Constraint surface Luciano Ristori - Vertex2002_7Nov02.ppt

  19. SVT Wedges Luciano Ristori - Vertex2002_7Nov02.ppt

  20. SVT system architecture Hit Finders raw data from SVX front end Sequencer Associative Memory COT tracks fromXTRP roads 12 fibers hits Track Fitter to Level 2 Merger hits Hit Buffer x 12 phi sectors Luciano Ristori - Vertex2002_7Nov02.ppt

  21. INFN INFN & Geneva University of Chicago SVT: board count • Hit Finders 42 • Mergers 16 • Sequencers 12 • AMboards 24 • Hit Buffers 12 • Track Fitters 12 • Spy Controls 8 • XTFA 1 • XTFB 2 • XTFC 6 • Ghostbuster 1 + spares TOTAL 136 Luciano Ristori - Vertex2002_7Nov02.ppt

  22. CPU Hit Finder Merger XTFA Tracer XTFB Sequencer Hit Buffer Spy Control Associative Memory XTFC Track Fitter b0svt00 b0svt07 b0svt06 b0svt05 b0svt01 b0svt02 b0svt03 b0svt04 SVT: board and crate layout Luciano Ristori - Vertex2002_7Nov02.ppt

  23. Hit Buffer board Luciano Ristori - Vertex2002_7Nov02.ppt

  24. Hit Finder board Luciano Ristori - Vertex2002_7Nov02.ppt

  25. Merger board Luciano Ristori - Vertex2002_7Nov02.ppt

  26. SVT crates in CDF counting room Luciano Ristori - Vertex2002_7Nov02.ppt

  27. Impact parameter vs. phi Raw x phi d y d d Subtracted d = y cos(phi) – x sin(phi) phi Luciano Ristori - Vertex2002_7Nov02.ppt

  28. SVT: beam profile Impact parameter distribution This distribution is interpreted as the convolution of the actual transverse size of the beam spot with the impact parameter resolution of the SVT sigma ~ 50 um ~ 43 um + 25 um SVT resolution beam spot size Luciano Ristori - Vertex2002_7Nov02.ppt

  29. Tevatron Beam Moves! Beam center at beginning of store normally stable within 20 microns. Drift during the duration of a store of 20 to 30 microns in x,y (often correlated) Beam slope more stable (variation <20 microradians) 25 microns TeV store ~12 hours x position (m) x slope (rad) y position (m) y slope (rad) Luciano Ristori - Vertex2002_7Nov02.ppt

  30. Hadronic B decays with SVT Two paths @ 3 x 1031 cm-2 s-1 • L1: • Two XFT tracks • Pt > 2.5 GeV; Pt1 + Pt2 > 6.5 GeV •  < 135° • L2: • d0>100 m for both tracks • Validation of L1 cuts with >20° • Lxy > 200 m • d0(B)<140 m • L1: • Two XFT tracks • Pt > 2.5 GeV; Pt1 + Pt2 > 6.5 GeV •  < 135° • L2: • d0>120 m for both tracks • Validation of L1 cuts with >2° • Lxy > 200 m • d0(B)<140 m ~ 3 KHz ~ 5 Hz Many body decays Two body decays Luciano Ristori - Vertex2002_7Nov02.ppt

  31. CDF as a Charm factory? Luciano Ristori - Vertex2002_7Nov02.ppt

  32. Fully Hadronic B decays Luciano Ristori - Vertex2002_7Nov02.ppt

  33. The design and construction of SVT was a significant step forward in the technology of fast track finding We use a massively parallel/pipelined architecture combined with some innovative techniques such as the associative memory and linearized track fitting SVT is now fully commissioned and we have shown we can handle all the technical challenges related to detector and beam alignment in real time Performance of SVT is as expected CDF is triggering on impact parameter and collecting data we hope will soon lead to significant physics results SUMMARY Luciano Ristori - Vertex2002_7Nov02.ppt

More Related