Liang HAN University of Manchester

December 31th, 2002 Liang HAN 1

Liang HANUniversity of Manchester

Central Fiber Track Trigger System

I. CFT & CTTT

II. Simulator: l1ft2b

III. First real L1CTT

IV. Run2a

V. Run2b

VI. Summary


L1 & L2 trigger


Dzero Upgrade Tracker


Picture: recod tracks in CFT


I. Central Fiber Track Trigger

a) 8 cylinders: Layer A,H

b) Axial doublet fibers per Layer

c)

d) in rphi: 80 Sectors, 10 Octants

Provide pT Track Trigger in xy-plane


Alignment cylinders: Fibers of 1 super Layer/sector:

Pictures of CFT Pictures of CFT


1 “sector”


DDoublet[k] = oublet[k] = { !inner(k-1) & outer(k) } ||{ !inner(k-1) & outer(k) } || innerinner((k)k)

CFT axial doublets are formed using two interleaved CFT fiber layers as follows:

k+1

k

k

k+1

k-1

k-1

increasing phi(looking NORTH at SOUTH face of detector)

CFT Axial Doublet


CTTT Algorithm

Stable charged from (0,0) in 2T Bz

where in Dzero, in cm and pT in GeV

ii rpT

kQ

0

0 5.0

ir006.00 k

pTNiFiber Fibersi 2

][


Pre-programmed Trigger lookup table: 8 Doublet Equation

(A,B,C,D,E,F,G,H)

Ptmin

(GeV)

Ptmax

(GeV)

Intacc relacc

0 1 1 1 1 1 1 0 -.161E+02-.119E+02 25160 0.357E-02

5 5 5 5 4 3 1 0 -.351E+01-.307E+01 92610 0.132E-01

-2 -2 -1 -1 -1 -1 0 0 0.18E+02 0.525E+02

57220 0.813E-02

11 12 12 11 10 7 4 1 -.169E+01-.162E+01 19890 0.283E-02

… … … … …

Hit Paten )/1/1(

2

maxmin ptptpT

“Equation”


1) Exclusive pTbin:

2) Inclusive Terms:

PT1 pT>10PT2 10>pT>5PT3 5>pT>3PT4 3>pT>1.5

TTK10 >=1 PT102TTK10 >=2 PT10

TTK5 >=1 PT52TTK5 >=2 PT5

… …

Trigger pTbin & AndOr Terms:


L1CTT framework


Simulate CTTT system, follows Trigger framework as close as possible, aim to Run2b Algorithm study:

1) CFT axial hits(ADC cut)2) Trigger Cluster, i.e. Doublet/Singlet (Algorithm)3) different Equations (Algorithm)4) Equation-Cluster match5) matched tracks reported

II. Simulator: lft2b

CTTTCTTTframeworkframework

SimulatorSimulator

l1ft2bl1ft2bOnlineOnline

platformplatform


III. First real L1CTT

L1CTT started working this November, many strange of online Platform have been observed.

l1ft2b is considered as close to the frameworkas possible, so a good tool to understand what’swrong. Focus on highest pTbin PT1


Phi distribution of online TTK10 triggered events:Phi distribution of online TTK10 triggered events:

Octant 2&7 screwed upOctant 2&7 screwed up!!!!

what understood


MaxpT distribution of MaxpT distribution of l1ft2bl1ft2b for for 37473747 events triggered by events triggered by online TTK10online TTK10

20492049 out of out of 37473747, why?, why?

what not understood yet


IV. Run2a Doublet EquationIV. Run2a Doublet Equation

PT1 eff of current online on single muon from(0,0)PT1 eff of current online on single muon from(0,0)


Problem of current EquationProblem of current Equation

Current online(Current online(nominalnominal):):• 80 sectors: 80 sectors: identicalidentical• designed Layer position: designed Layer position: eg HX eg HX 51.5cm51.5cm• tracks from (tracks from (0,00,0) )

As-builtAs-built::• sectors: sectors: individualindividual!!!!!!• Layer shift: eg HX Layer shift: eg HX 52.0cm52.0cm• beam-spot: eg beam-spot: eg (-0.3,0.339)mm(-0.3,0.339)mm

problem:PT1 eff of problem:PT1 eff of nominalnominal on pT=15 single muonon pT=15 single muon99.199.1% % 61.161.1% % (+20.7% PT2)(+20.7% PT2)

answer: new answer: new as-builtas-built equations(Graham Wilsom) equations(Graham Wilsom)


New as-built EquationNew as-built Equation

check check as-builtas-built with data: 143 recod dimuon(pT>15) with data: 143 recod dimuon(pT>15)

216

202

)60,(#

)01.0,1(#

M

PTPT1 effPT1 eff 93.593.5%%


Sample Equation PT1 efficiencyMC mu(15),mb0,

no ADC cutnominal ~99.5%

MC mu(15),mb7.5,

no ADC cutnominal 98.5+/-0.19%

MC mu(15),mb7.5,

1.5pe cutnominal 97.6+/-0.24%

Dimu Data (pT>15) as-built 93.5+/-1.7%

MCMC expect ~ expect ~9999% PT1 eff with current luminosity, % PT1 eff with current luminosity, but but as-builtas-built only gives ~ only gives ~9393% on data, i.e. % on data, i.e. 66% ineff % ineff


Weakness of Doublet Veto

Doublet[2] Doublet[1]

Track hit

Noise hit


Current CFT Layer occupancy


Causes of ineff:Causes of ineff:• multiple scattering: multiple scattering: unlikelyunlikely, ineff independent with track pT, ineff independent with track pT• Doublet Veto: Doublet Veto: unlikelyunlikely, 1D-shift mostly occur at D Layer, 1D-shift mostly occur at D Layer• beam shift: beam shift: unlikelyunlikely, include 250micron smearing , include 250micron smearing • inperfect CFT geometry: inperfect CFT geometry: possiblepossible, some fibers are not parellel to z, some fibers are not parellel to z

Risk: the number of equations increase, eg Risk: the number of equations increase, eg

nominal 16k nominal 16k to current to current as-built 18kas-built 18k fake ratefake rate


V. Run2b developmentV. Run2b development

Run2a Run2b

Luminosity 2E30 2E31

Bench(ns) 396 132

No of mb ~2 ~6-7

Bad news: we may never come to 132ns in Run2bBad news: we may never come to 132ns in Run2b


Weakness of Doublet AlgorithmWeakness of Doublet Algorithm

A) A) Veto:Veto: pT=15 muons in Pythia mb7.5, Doublet PT1 eff ispT=15 muons in Pythia mb7.5, Doublet PT1 eff is

97.697.6%% (~99% in mb0) (~99% in mb0)

B)B) Fake: Fake: pure Pythia mb7.5 events, from random noise Doublet will havepure Pythia mb7.5 events, from random noise Doublet will have

11%% triggered by fake PT1triggered by fake PT1

L1 can only survive with greater than L1 can only survive with greater than 0.20.2% fake in % fake in Run2b luminosityRun2b luminosity

Doublet can’t survive in Run2b luminosity!!


Worst-case scenario:Isajet

A)A) Eff lost due to Veto: Eff lost due to Veto:

B)B) Fake rate: Fake rate:


Worst-case scenario(cont.)


Solution: Solution: SingletSinglet or mixture or mixture


16 Singlet

Advantage:A) no Veto: efficiency unchanged with mb

B) reject fake: finer Trigger Bin

Problem: PT1 part, with nominal+1.5pe fiber efficiency cut

4800k!!! 300 times FPGA resources of current online Run2a


Trim Equations

Tried and tested 13 different algorithms, kill most of themand come to the “final” choice :

A) Mixed Algorithm: pT>5 part, pure 16 Singlet, i.e. “abcdefgh” pT<5 part, Singlet-Doublet mixture, i.e. “ABCDefgh”

B) tricky pruning: to get rid of low acceptance ones


Tricky pruning

1) Remove equations with Doublet missing2) Cut on “intacc”(MC hits)3) Remove/combine redundancy

Come to “16v5PT12_acc200rr” and “12v4PT34_acc10rr”


Result of latest Run2b Algorithm

“abcdefgh”

“ABCDefgh”

• 98% PT1 eff, and 0.031% fake in pmb7.5

• Total come to 31k, risk of overflow FPGA


What if can’t go to 132ns in Run2b

Run2b Singlet Algorithm


How worse it would be


VI. SummaryVI. Summary

CTTT simulator:

online CTTT: start to work, but

Run2a: real as-built equation is under development, need more Zmumu data for calibration

Run2b: new algorithm is suggested; need Run2a inform to make Run2b real

CTTTCTTTframeworkframework

SimulatorSimulator

l1ft2bl1ft2b

SimulatorSimulator

l1ft2bl1ft2bOnlineOnline

platformplatform why?why?


No. of Doublet/sector in the TTK10 triggered events, given by onlineNo. of Doublet/sector in the TTK10 triggered events, given by online

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