ecl trigger overview
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2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
ECL Trigger overviewByungGu Cheon (SKKU)
Outline ECL calorimeter ECL trigger scheme & performance Recent trigger upgrade status ECL trigger system @ 1035 super-KEKB Summary
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Belle ECL (Electromagnetic Calorimeter)
8736 CsI(Tl) crystals
& e energy and position measurement
Trigger info. generation : powerful tool to suppress BG events.
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
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) : ETC > 100MeV
– Energy trigger : Total energy sum > 1GeV– Isolated cluster counting trigger : # of clusters > 3– Bhabha & cosmic-veto triggers
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger Cell Map
Analog cell
Physics trigger region (Etot / ICN)
576 Trigger cells ICN
136 Analog cells ETOT & Bhabha/
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Bhabha/ trigger Using Back-to-Back condition of each bhabha type depending on LAB angle with high energy threshold.
Bhabha type Threshold (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
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Cosmic veto trigger Using naive event topology of hadronic process events against cosmic ray and beam BG topologies.
r- Plane in Barrel Region
DBCAOLD
AB
C D DC
AB
IR
)()( FEBarrelFEOLDNEW
IR
energy trigger effi.
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger Scheme
Energy trigger and Bhabha trigger
Isolated cluster counting trigger
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger efficiency
Energy trigger ICN trigger Bhaha trigger
~ 97%
~ 95% ~ 99%
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger rate tendency
ETOT>0.5GeV ETOT>1.0GeV ETOT>3.0GeV
Trigger rate : 900Hz, 400Hz, 250Hz @ 7x1033
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger rate tendency
ICN bit0
trigger rates @ 7x1033 :
10KHz, 1.3KHz,
55Hz, 17HzICN bit2 ICN bit3
ICN bit1BhabhaCosmicICN 3
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Trigger rate tendency
Bhabha trigger rate @ 7x1033 :
350Hz, 100Hz,
10KHz, 14KHz
Pre-Bhabha
Cosmic Timing
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
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 eeX – Matching with track trigger bits
• MC simulation study– Bhabha trigger efficiency : 99% X trigger efficiency : 37% 72%
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Electronics flow chart
New trigger system
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Hardware in new system
BTLTPSD
CVC
ETM
(32)
(32) (4)
CCM & EBM
STM
AAA
Newly added chain
GDL
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Bhabha/ tagging
8 overlapped sectors
r-plane
5
1
r-zplane
Back
to b
ack
for
Back
to b
ack
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
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Bhabha, and X
r- plane
8 overlapped sectors
421 5 876 3
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 !
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Logic simulation study
5
1
TRK 1 & 5& &
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Threshold calibration
Type 1 2 3 4 5 6 7 8 9 10 11
FWD 4 4.5 4.5 4.5 4.5 4 5 4 4 ---- 4.5
BWD 3 3 3 3.5 3 3 3 3.5 4 3.5 ----
Threshold table for r-z Threshold for r-
D1
D
D
5
3GeV
3GeV
7GeV
( GeV )
Threshold calculation
ON ON+OFF
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Threshold calibration
Setting of threshold for all channels
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
Expected L1 trigger rates @ 1035 super-KEKB
Trigger bit Rate @ 1035
ETOT>0.5GeV 6.5K
ETOT>1.0GeV 3.4K
ETOT>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: ETC & physics trigger region Optimize btw trig efficiecny and trig rates
TC pulse width : 1s TC occupancy < 10KHz @ 1035
Current L1 trigger system can be kept.
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
L2/L3 trigger @ 1035 super-KEKB
It’s rather difficult to make concrete plan to prepare L2/L3 triggers before Trigger+DAQ readout scheme is finalized.
preAmp Shaper Flash-ADC
ECL L1 trigger
L2/L3 PC farm
GDL
Software triggers for ECL• ET balance• ECL/CDC matching• TC hitmap pattern• Total Energy• Cluster finding logic
fast
slow
CDC L1 trigger
KLM L1 trigger
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
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/cm3
X0
cm
em
nm
Nph/MeV decay
nsec
CsI(Tl) 4.51 1.86 550 52000 1000
CsI 4.51 1.86 305/400 5000 10/1000
2002.10.28-29 Mini-Trigger/DAQ workshop,OCU B.G.Cheon
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 1035 super-KEKB.• Trigger electronics R&D work is necessary if pure-CsI is chosen
to endcap calorimeter.
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