1. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU ECL Trigger overview ByungGu Cheon (SKKU) Outline  ECL calorimeter  ECL trigger scheme & performance  Recent trigger upgrade status  ECL trigger system @ 10 35 super-KEKB  Summary

2. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Belle ECL (Electromagnetic Calorimeter)  8736 CsI(Tl) crystals   & e  energy and position measurement  Trigger info. generation : powerful tool to suppress BG events.

3. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU ECL Trigger Trigger concept/requirement –Suppress beam-BG and cosmic events –Separate physics events from Bhabha/  –Fast trigger decision < 1.85  s –Good timing resolution Trigger condition –Trigger Cell (4x4 matrix) : E TC > 100MeV –Energy trigger : Total energy sum > 1GeV –Isolated cluster counting trigger : # of clusters > 3 –Bhabha & cosmic-veto triggers

4. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger Cell Map Analog cell Physics trigger region (Etot / ICN) 576 Trigger cells  ICN 136 Analog cells  E TOT & Bhabha/ 

5. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Bhabha/  trigger Using Back-to-Back condition of each bhabha type depending on  LAB angle with high energy threshold. Bhabha typeThreshold (GeV) Type 1 5.0 Type 2 5.5 Type 3 5.0 Type 4 5.0 Type 5 5.0 Type 6 5.0 Type 7 5.0 Type 8 5.0 Type 9 5.0 Type 10 5.0 Type 11 3.0

6. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Cosmic veto trigger Using naive event topology of hadronic process events against cosmic ray and beam BG topologies. r-  Plane in Barrel Region AB CDDC A B IR energy trigger effi.

7. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger Scheme Energy trigger and Bhabha trigger Isolated cluster counting trigger

8. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger efficiency Energy triggerICN triggerBhaha trigger  ~ 97%  ~ 95%  ~ 99%

9. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger rate tendency E TOT >0.5GeV E TOT >1.0GeV E TOT >3.0GeV Trigger rate : 900Hz, 400Hz, 250Hz @ 7x10 33

10. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger rate tendency ICN bit0 trigger rates @ 7x10 33 : 10KHz, 1.3KHz, 55Hz, 17Hz ICN bit2ICN bit3 ICN bit1

11. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Trigger rate tendency Bhabha trigger rate @ 7x10 33 : 350Hz, 100Hz, 10KHz, 14KHz Pre-Bhabha CosmicTiming

12. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Motivation for new trigger system Weakness of Bhabha trigger for e + e -   X event selection Separate Bhabha and  events in the trigger level Expect much stable Bhabha/  tagging than current system Using  directional Back-to-Back condition –Tag of ee  X –Matching with track trigger bits MC simulation study –Bhabha trigger efficiency : 99% –  X trigger efficiency : 37%  72%

13. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Electronics flow chart New trigger system

14. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Hardware in new system BTLTPSD CVC ETM (32) (4) CCM & EBM STM AAA Newly added chain GDL

15. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Bhabha/  tagging 8 overlapped sectors r-  plane 5 1 r- z  plane Back to back for  Back to back for  Bhabha =  &  !!  For ,  16 overlapped signals @ r-z plane.  For ,  8 overlapped signals @ r-  plane.  4 back to back combined signals.  4 back to back combined signals with different threshold

16. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Bhabha,  and  X r-  plane 8 overlapped sectors 42158763 84736251 ECL CDC Back-to-Back  trigger : ECL(1&5) & CDC(0&0) Bhabha trigger : ECL(1&5) & CDC(1&5)  X trigger : ECL(1)+CDC(0) & Bhabha/  veto 5 1 Generate triggers by matching with track information !

17. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Logic simulation study 5 1 TRK 1 & 5 &&

18. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Threshold calibration Type1234567891011 FWD44.5 4544----4.5 BWD3333.5333 4 ---- Threshold table for r-z Threshold for r-  D 1 D D 5 3GeV 7GeV ( GeV ) Threshold calculation ONON+OFF

19. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Threshold calibration Setting of threshold for all channels

20. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Expected L1 trigger rates @ 10 35 super-KEKB Trigger bit Rate @ 10 35 E TOT >0.5GeV 6.5K E TOT >1.0GeV 3.4K E TOT >3.0GeV 2.5K ICN bit-0 18.0K ICN bit-1 5.0K ICN bit-2 0.5K ICN bit-3 0.2K Bhabha 5.0K Pre-Bhabha 1.5K Cosmic 38.0K CsI timing 110.0K  Estimated with current trigger performance  Depend on super-KEKB beam condition  Some flexibilities:  E TC & physics trigger region  Optimize btw trig efficiecny and trig rates  TC pulse width : 1  s  TC occupancy < 10KHz @ 10 35  Current L1 trigger system can be kept.

21. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU L2/L3 trigger @ 10 35 super-KEKB  It ’ s rather difficult to make concrete plan to prepare L2/L3 triggers before Trigger+DAQ readout scheme is finalized. preAmpShaper Flash-ADC ECL L1 trigger L2/L3 PC farm GDL Software triggers for ECL E T balance ECL/CDC matching TC hitmap pattern Total Energy Cluster finding logic fast slow CDC L1 trigger KLM L1 trigger

22. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU CsI(Tl) Barrel + pure-CsI Endcap  Current trigger system should be modified to accommodate both outputs in the trigger level.  Simple(?) concept to modify endcap electronics :  preAmp  fast shaper  STM for Barrel region  preAmp  new fast shaper  STM for endcap region  pulse height correction + active timing delay  potential problem of trigger timing resolution Crystal  g/cm 3 X 0 cm em nm N ph /MeV  decay nsec CsI(Tl) 4.51 1.86 550 52000 1000 CsI 4.51 1.86305/400 500010/1000

23. B.G.Cheon2002.10.28-29Mini-Trigger/DAQ workshop,OCU Summary Current ECL trigger works well and new Bhabha trigger system is in progress. We expect the new system to be implemented before KEKB winter shutdown. Current ECL trigger system can be used at 10 35 super-KEKB. Trigger electronics R&D work is necessary if pure-CsI is chosen to endcap calorimeter.