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Central Fiber Track Trigger System. Liang HAN University of Manchester. 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.

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slide1

Central Fiber Track TriggerSystem

Liang HAN

University of Manchester

I. CFT & CTTT

II. Simulator: l1ft2b

III. First real L1CTT

IV. Run2a

V. Run2b

VI. Summary

Liang HAN

slide5

I. Central Fiber Track Trigger

Provide pT Track Trigger in xy-plane

a)8 cylinders: Layer A,H

b) Axial doublet fibers per Layer

c)f~(0,2p), h~(-1.5,+1.5)

d) in rphi: 80 Sectors, 10 Octants

Liang HAN

slide6

Pictures of CFT

Alignment cylinders:

Fibers of 1 super Layer/sector:

Liang HAN

slide8

CFT Axial Doublet

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

increasing phi

(looking NORTH at SOUTH face of detector)

k+1

k

k-1

k+1

k

k-1

Doublet[k] = { !inner(k-1) & outer(k) } ||inner(k)

Liang HAN

slide9

CTTT Algorithm

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

where in Dzero, in cm and pT in GeV

Liang HAN

slide10

“Equation”

Pre-programmed Trigger lookup table:

Hit Paten

Liang HAN

slide11

Trigger pTbin & AndOr Terms:

1) Exclusive pTbin:

2) Inclusive Terms:

Liang HAN

slide13

II. Simulator: lft2b

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 match

5) matched tracks reported

Online

platform

CTTT

framework

Simulator

l1ft2b

Liang HAN

slide14

III. First real L1CTT

L1CTT started working this November, many

strange of online Platform have been observed.

l1ft2b is considered as close to the framework

as possible, so a good tool to understand what’s

wrong. Focus on highest pTbin PT1

Liang HAN

slide15

what understood

Phi distribution of online TTK10 triggered events:

Octant 2&7 screwed up!!

Liang HAN

slide16

what not understood yet

MaxpT distribution of l1ft2b for 3747 events triggered by online TTK10

2049 out of 3747, why?

Liang HAN

slide17

IV. Run2a Doublet Equation

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

Liang HAN

slide18

Problem of current Equation

  • Current online(nominal):
  • 80 sectors: identical
  • designed Layer position: eg HX 51.5cm
  • tracks from (0,0)
  • As-built:
  • sectors: individual!!!
  • Layer shift: eg HX 52.0cm
  • beam-spot: eg (-0.3,0.339)mm
  • problem:PT1 eff of nominalon pT=15 single muon

99.1% 61.1% (+20.7% PT2)

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

Liang HAN

slide19

New as-built Equation

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

93.5%

PT1 eff

Liang HAN

slide20

MC expect ~99% PT1 eff with current luminosity,

but as-built only gives ~93% on data, i.e. 6% ineff

Liang HAN

slide21

Weakness of Doublet Veto

Track hit

Noise hit

Doublet[2] Doublet[1]

Liang HAN

slide23

Causes of ineff:

  • multiple scattering: unlikely, ineff independent with track pT
  • Doublet Veto: unlikely, 1D-shift mostly occur at D Layer
  • beam shift: unlikely, include 250micron smearing
  • inperfect CFT geometry: possible, some fibers are not parellel to z
  • Risk: the number of equations increase, eg

nominal 16k to current as-built 18kfake rate

Liang HAN

slide24

V. Run2b development

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

Liang HAN

slide25

Weakness of Doublet Algorithm

A) Veto:

pT=15 muons in Pythia mb7.5, Doublet PT1 eff is

97.6% (~99% in mb0)

B) Fake:

pure Pythia mb7.5 events, from random noise Doublet will have

1%triggered by fake PT1

L1 can only survive with greater than 0.2% fake in Run2b luminosity

Doublet can’t survive in Run2b luminosity!!

Liang HAN

slide26

Worst-case scenario:Isajet

  • A) Eff lost due to Veto:
  • B) Fake rate:

Liang HAN

slide29

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

Liang HAN

slide30

Trim Equations

Tried and tested 13 different algorithms, kill most of them

and 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

Liang HAN

slide31

Tricky pruning

1) Remove equations with Doublet missing

2) Cut on “intacc”(MC hits)

3) Remove/combine redundancy

Come to “16v5PT12_acc200rr” and “12v4PT34_acc10rr”

Liang HAN

slide32

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

Liang HAN

slide33

What if can’t go to 132ns in Run2b

Run2b Singlet Algorithm

Liang HAN

slide35

VI. 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

Simulator

l1ft2b

CTTT

framework

Online

platform

Simulator

l1ft2b

why?

Liang HAN