Track Fitting and Comparator Track Fitting and Comparator ResultsResults

Emu meeting @ UC DavisFeb. 26, 2005

Yangheng ZhengUniversity of California, Los Angeles

Motivation & Introduction

Results

02/26/2005Emu meeting @ UC Davis2

MotivationsMotivations

Check output from comparator chips (for both ME2/2 and ME1/1)

Get familiar with Stan’s track-fitting utility package (TrackFnd)

Test the unpacking software (ORCA/EmuDAQ) for test-beam 2004 data

Look at ME1/1 data from TB2004

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Stan’s Track Fitting FrameworkStan’s Track Fitting Framework

Pedestal Subtraction Precision Sampling Time buckeye shaping Cross Talk is a function of ts (capacitative+slightly

resistive coupling between adjacent strips) lookup table

Cathode Noise Correlation unfired events Fitting Gatti distribution hit position / each layer Track Finding Kalman Filter Track Fitting A straight line least squares fit Details can be found:

http://www.physics.ohio-state.edu/~durkin/testbeam03/TrackFnd.htm

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Data for Gatti FittingData for Gatti Fitting

)50()50()50(

)0()0()0(

)50()50()50(

RML

RML

RML

qqq

qqq

qqq

stripsti

me

bin

s

Largest pedestal subtracted ADC value

INPUT DATA:

OUTPUT: track hit position for each layer through the least squares fitting

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Something NewSomething New New interface between TrackFnd and

ORCA/EmuDAQ Add options of gMinuit for fitting

distributions of buckeye and Gatti Change pedestal subtraction method New constants for ME11

cross talk cathode noise correlation Gatti parameters strip width and no staggering

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Buckeye ShapingBuckeye Shapingcs ttt

s ett /)(4)(

4*tc

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Peaking Time Peaking Time ttccME22 (tc33.25ns)

ME11(tc28ns)

ME11: smaller gas gap and wire spacing shorter drifting time

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Peak Charge Time BinsPeak Charge Time Bins

ME22 (TB2003) ME22 (TB2004) ME11 (TB2004)

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Pedestal SubtractionPedestal Subtraction

Standard method: subtracting first two time samples

Method 2: pedestals empty event (lookup table for every strip)

Method 3: pedestals fitting all available time samples for every event (buckeye shape + constant pedestal)

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Pedestal Subtraction (cont.)Pedestal Subtraction (cont.)

Method 1 – Method 2 Method 3 – Method 2ME22 (TB2004)

Mean 1.041

RMS 3.17

Mean 4.322

RMS 5.901

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Pedestal Subtraction (cont.)Pedestal Subtraction (cont.)

ME22 (TB2004)

---- Method 1

---- Method 2

---- Method 3

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Cross Talk Cross Talk a function of ts

determined by tracks passed within 0.05 strip width of the center of the strip

ME22(TB2003)

ME22(TB2004)

ME11(TB2004)

small statistics

ts (ns)

cro

ss t

alk

frac

tio

n

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Cathode Noise CorrelationCathode Noise Correlation Determined from unfired strips For time bins i and j,

For time bins 3, 4, 5, 6 (ADC counts)

For ME22, TB2003 and TB2004 show similar results ME11 shows different noise correlation No correlations between adjacent strips’ time bins (<1

count)

a

jja

iiajiij qqqqCC ))((

2.123.62.46.4

3.64.129.69.4

2.49.60.148.8

6.49.48.84.16

9.93.52.32.4

3.57.101.60.4

2.31.67.115.7

2.40.45.71.14

2.79.35.20.3

9.37.70.49.2

5.20.45.79.3

0.39.29.37.7ME22 (TB2003) ME22 (TB2004) ME11 (TB2004)

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Gatti ParametersGatti Parameters

half gas gap (h parameter) configuration: ME22 4.75mm, ME11 3.00mm fitting: ME22 4.91mm, ME11 2.99mm

strip width ME22 8.5-16.0mm, ME11 3.15-7.6mm

number of wire group per layer ME22 64, ME11 48

strip staggering ME22 0.5 strip, ME11 no staggering

02/26/2005Emu meeting @ UC Davis15

2 2 of Gatti Fittingof Gatti Fitting

)()( 1

,

2 xqqxqq expj

measjij

strips ji

expi

measi V

measj

measiijij qqsyserrCV

NDOF: 9 - 3 - 1 = 5

ME22 (TB2004) ME11 (TB2004)

Investigating the large tail effect

0.08 for ME22=

2 2

En

trie

s

En

trie

s

Mean 4.99

RMS 3.16

Mean 4.999

RMS 3.16

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Event DisplaysEvent DisplaysME22 (TB2004) ME11 (TB2004)

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Residue (3Residue (3rdrd Layer) Layer)

ME22 (TB2004) ME11 (TB2004)

sigma=0.0178 sigma=0.0177

3rd layer removed from track fitting

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Comparator Ouput ResolutionComparator Ouput Resolution

fitted track position - comparator output

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Left Half Hits vs Right Half HitsLeft Half Hits vs Right Half Hits

wrong output due to the ambiguous charge difference (see next slide)

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Output ProbabilityOutput Probability

wrong assignment due to the ambiguous charge difference

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Output EfficiencyOutput Efficiency

correct comparator output

correct strip# output

comparator output residue within ¾ strip

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SummarySummary Unpacking software seems robust Small changes applied to TrackFnd class For ME22, results of track fitting of

TB2003 can be fully reproduced. For ME11, the large tail effect of 22 and

systematic errors are under investigation Comparator chip produced reasonable

results for both ME11 and ME22

02/26/2005Emu meeting @ UC Davis23

NextNext

need to understand ME11 data better more refinements can be done

gain effect cross talk as a function of chamber

position geometry constants