B.G.Cheon Mini-Trigger/DAQ workshop,OCU ECL Trigger overview ByungGu Cheon (SKKU) Outline  ECL calorimeter  ECL trigger scheme & performance  Recent trigger upgrade status  ECL trigger super-KEKB  Summary

B.G.Cheon Mini-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.

B.G.Cheon Mini-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

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

B.G.Cheon Mini-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 Type Type Type Type Type Type Type Type Type Type

B.G.Cheon Mini-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.

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Trigger Scheme Energy trigger and Bhabha trigger Isolated cluster counting trigger

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

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Trigger rate tendency E TOT >0.5GeV E TOT >1.0GeV E TOT >3.0GeV Trigger rate : 900Hz, 400Hz, 7x10 33

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

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

B.G.Cheon Mini-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%

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Electronics flow chart New trigger system

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

B.G.Cheon Mini-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 r-z plane.  For ,  8 overlapped r-  plane.  4 back to back combined signals.  4 back to back combined signals with different threshold

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Bhabha,  and  X r-  plane 8 overlapped sectors 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 !

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Logic simulation study 5 1 TRK 1 & 5 &&

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Threshold calibration Type FWD BWD Threshold table for r-z Threshold for r-  D 1 D D 5 3GeV 7GeV ( GeV ) Threshold calculation ONON+OFF

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Threshold calibration Setting of threshold for all channels

B.G.Cheon Mini-Trigger/DAQ workshop,OCU Expected L1 trigger super-KEKB Trigger bit E TOT >0.5GeV 6.5K E TOT >1.0GeV 3.4K E TOT >3.0GeV 2.5K ICN bit K 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 <  Current L1 trigger system can be kept.

B.G.Cheon Mini-Trigger/DAQ workshop,OCU L2/L 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

B.G.Cheon Mini-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) CsI / /1000

B.G.Cheon Mini-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 super-KEKB. Trigger electronics R&D work is necessary if pure-CsI is chosen to endcap calorimeter.