1 / 27

L1 Trigger Strategy

L1 Trigger Strategy. Ted Liu, Lawrence Berkeley Lab (for the trigger group). L1 Trigger Requirements and Trigger Lines L1 Trigger performance Background Study Improving Performance : near-term strategy Future Prospect: long-term strategy summary.

tolla
Download Presentation

L1 Trigger Strategy

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. L1 Trigger Strategy Ted Liu, Lawrence Berkeley Lab (for the trigger group) • L1 Trigger Requirements and Trigger Lines • L1 Trigger performance • Background Study • Improving Performance: near-term strategy • Future Prospect: long-term strategy • summary Ted Liu, July 5,00, idea on Ztrigger

  2. Trigger Line Definition/Convention DCT Objects: B: short track reaching SL5, Pt ~120 MeV A: long track reaching SL10, Pt ~180 MeV A’: high Pt track reaching SL10, Pt > 800 MeV EMT Objects: M: minimal ionizing cluster, E >100 MeV G: intermediate energy cluster, E >300 MeV E: high energy cluster, E >700 MeV Y: backward barrel cluster, E >1 GeV IFT Objects: 1U: 1 high P muon in backward endcap o B*,M*...* means back-to-back objects(>120 ) D2 = 2B&1A, D2* = B*&1A D2*+ = B*&1A&1A’ , A+ = A&A’ Ted Liu, July 5,00, idea on Ztrigger

  3. Trigger Lines for Hadronic Events run9304 Requirements: B Physics Pure DCT CP Channels: high eff. Non-CP channels: high + precise eff. DCT + EMT Continuum High & precise eff. for background sub. Pure EMT Strategy for eff. Measurements: orthogonal lines redundant lines record all trigger DAQ data prescaled lines Ted Liu, July 5,00, idea on Ztrigger

  4. From Su Dong Use orthogonal DCT-EMT lines to study eff. Total eff for hadron skim: (EMT OR DCT) > 99.3% Ted Liu, July 5,00, idea on Ztrigger

  5. run9304 Trigger Lines for non-physics Events Requirements: Luminosity, calibration: 2-prong ee, High + precise eff. Pure DCT Calibration, beam monitor: 1-prong ee, DCT + EMT  only Pure EMT Background monitoring Background&Trigger studies Ted Liu, July 5,00, idea on Ztrigger

  6. Trigger Lines for  and 2 Events Requirements:  Physics Pure DCT Rare & Asy.: high eff. Branch Ratios: precise eff. DCT + EMT 2 Physics precise eff. Pure EMT Shortcomings: All unprescaled lines have high Pt cut (800MeV) and with back-to-back requirement. No unprescaled orthogonal lines. All high eff. Lines have to be prescaled. Expected @ high background rate, will try to improve… add 2BM+1AM, lower Pt cut? Ted Liu, July 5,00, idea on Ztrigger

  7. L1 Strategy to improve performance Better Combination of trigger lines: DCT+EMT phi matching Give up some orthogonal lines ... Improve trigger objects: Short-term: PTD ---> DOCAD Long-term: DOCAD --> DOCAZD? Need good understanding of background --> next Ted Liu, July 5,00, idea on Ztrigger

  8. LER HER Single beam LER HER L1 pass thr. events Z distribution From S. Petrak Ted Liu, July 5,00, idea on Ztrigger

  9. LER HER LER HER Single beam L1 pass thr. events x-z view Ted Liu, July 5,00, idea on Ztrigger Many tracks from beampipe: off Z --> off IP in x-y

  10. Drift Chamber DCT Trigger Hardware Binary Track Linker (BLT x1) Coarse data for all supercell hits Trigger data 24 Gbits/s A, B 16 GLT 16 A’ Fine position data for segments found for axial SLs PT Discriminator PTD (x8) New idea Ted Liu, July 5,00, idea on Ztrigger DOCAD Track Segment Finder (x24) (only firmware change)

  11. Drift Chamber Trigger ( DCT ) The heart of DCT is the Track Segment Finder TSF continuously live image processor A novel method: using both occupancy and drift-time information, to find track segments continuously with: time resolution of ~ 100 ns, event-time jitter window ~ 100 ns spatial resolution ~ 1 mm used for track Pt Discrimination (1) send segment patterns downstream for L1 trigger decision making Upon a L1 accept: (2) send segment patterns to the DAQ system for use in Level 3 ... Track Segment Finder Ted Liu, July 5,00, idea on Ztrigger Use 24 TSF modules

  12. Ted Liu, July 5,00, idea on Ztrigger

  13. Ted Liu, July 5,00, idea on Ztrigger

  14. New DOCAD algorithm Current PTD algorithm (baseline design: simple algo.) A10 seed x x 800MeV Pt threshold (800MeV) 850MeV 900MeV SL7 1 GeV SL7 SL4 SL4 SL1 SL1 x x IP IP 4 hits on one track with ~1mm, should be able to tell whether the track is from IP Tracks (above threshold) coming from IP should leave all the hits in one of the slices Tracks not coming from IP will most likely leave hits in different slices Ted Liu, July 5,00, idea on Ztrigger

  15. Apply DOCAD algorithm to TSF data Hadron skim: signal PTD on Effect on Signal: Use hadron skim (~10% bkg) ~ 4% loss at turn on DOCAD on Effect on Background: Use single beam run L1 pass thr events Max Pt in the event 40% rejection on A’ line with simple algorithm PTD on Background rejection: 40% The goal here is not to find the best algorithm possible, but one which is easy to be implemented and with good performance DOCAD on Ted Liu, July 5,00, idea on Ztrigger LER single beam run: background

  16. Require 3/3 in ALL slices DOCAD algorithm: possible improvement TSF can determine segment location with 1 mm resolution only for 4/4 patterns But 20% signal loss The resolution is degraded for 3/4 patterns: Due to cell ineff.  1 2 x x x x x = x x + x x x x 3/4 4/4 4/4 1 <  < 2 calibrating 3/4 patterns should help 70% bkg rejection! using the  information should help (baseline design ignored ) Ted Liu, July 5,00, idea on Ztrigger Currently 3/4 pattern LUT is derived from 4/4 patterns

  17. L1 Long term strategy: cut in Z using TSF fine position info from stereo superlayers? The Drift Chamber ( DCH ) Cell size: 1.2 cm x 1.8 cm 10 superlayers of 4 layers each Axial and stereo alternate Ted Liu, July 5,00, idea on Ztrigger

  18. L1 long-term strategy: Can we cut in Z using TSF position info from stereo SLs? Stereo SLs --> Z Axial SLs --> DOCA DOCAZD Close to IP in z Cosmic ray events In other words: move some L3 DCH algorithm upstream to L1 (cut in doca&z) Off IP in z Tough but possible ! Ted Liu, July 5,00, idea on Ztrigger What to expect? The answer is in the TSF data we already have

  19. B1 B1 LER HER Lost particle interact with beampipe flange real collision due to a step in the synchrotron mask Track z distribution for L1 passthrough events Ted Liu, July 5,00, idea on Ztrigger

  20. Basic idea (~16 new DOCAZ boards in phi) Off Z track 40~50 or so slices in theta ~ 2 cm in z for SL2 TSF phi resolution ~ 1 mm Z resolution ~ 2 cm Ted Liu, July 5,00, idea on Ztrigger

  21. L1 long-term strategy: Can we cut in Z using TSF position info from stereo SLs? Stereo SLs --> Z Axial SLs --> DOCA DOCAZD Current “trigger volume” Possible improved “trigger volume”?? What to expect? The answer is in the TSF data we already have! Ted Liu, July 5,00, idea on Ztrigger

  22. Drift Chamber Upon a L1 Accept ... DAQ Using segments found by TSFs as seeds, fast algorithm applied to DCH data to further reject background... reduce the rate from 2 kHz to 100 hz. Level 3 Filter DAQ Fine position info for segments found for all superlayers Trigger data 24 Gbits/s Currently TSF provides fine position info for all SuperLayers to L3, only axial SLs info passed to PTD. Ted Liu, July 5,00, idea on Ztrigger Track Segment Finder (x24)

  23. One possible scenario Drift Chamber DAQ Level 3 Filter DAQ All track segments found Trigger data 24 Gbits/s A,B Supercell hits GLT DZ? Fine phi info for all(?) SLs DOCAZD ?? Ted Liu, July 5,00, idea on Ztrigger Track Segment Finder (x24)

  24. LER Ted Liu, July 5,00, idea on Ztrigger HER

  25. Ted Liu, July 5,00, idea on Ztrigger

  26. Ted Liu, July 5,00, idea on Ztrigger

  27. The Drift Chamber ( DCH ) 10 superlayers of 4 layers each Axial and stereo alternate Ted Liu, July 5,00, idea on Ztrigger

More Related