b.g.cheon2002.10.28-29mini-trigger/daq workshop,ocu ecl trigger overview byunggu cheon (skku)...

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


Belle ECL (Electromagnetic Calorimeter)

8736 CsI(Tl) crystals

& e energy and position measurement

Trigger info. generation : powerful tool to suppress BG events.


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


Trigger Cell Map Analog cell

Physics trigger region (Etot / ICN)

576 Trigger cells ICN

136 Analog cells ETOT & Bhabha/


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


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

ABIR

)()( FEBarrelFEOLDNEW

IR

energy trigger effi.


Trigger Scheme

Energy trigger and Bhabha trigger

Isolated cluster counting trigger


Trigger efficiency

Energy trigger ICN trigger Bhaha trigger

~ 97%

~ 95% ~ 99%


Trigger rate tendency

ETOT>0.5GeV ETOT>1.0GeV ETOT>3.0GeV

Trigger rate : 900Hz, 400Hz, 250Hz @ 7x1033



ICN bit0

trigger rates @ 7x1033 :

10KHz, 1.3KHz,

55Hz, 17HzICN bit2 ICN bit3

ICN bit1BhabhaCosmicICN 3



Bhabha trigger rate @ 7x1033 :

350Hz, 100Hz,

10KHz, 14KHz

Pre-Bhabha

Cosmic Timing


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%


Electronics flow chart

New trigger system


Hardware in new system

BTLTPSD

CVC

ETM

(32)

(32) (4)

CCM & EBM

STM

AAA

Newly added chainGDL


Bhabha/ tagging

8 overlapped sectors

r-plane

5

1

r-zplane

Back t

o bac

k for

Back t

o bac

k 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


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 !


Logic simulation study

5

1

TRK 1 & 5& &


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


Threshold calibration

Setting of threshold for all channels


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.


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


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


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.

b.g.cheon2002.10.28-29mini-trigger/daq workshop,ocu ecl trigger overview byunggu cheon (skku)...

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