ITS code StatusJune 7 2002

A. Badala’, R. Barbera, B. Batyunya, Y. Belikov, M. Bondila,

N. Bustreo, R. Caliandro,P. Cerello, E. Crescio, R. Fini,

E. Fragiacomo, J. Hubbel, E. Lopez, G. Lo Re, B. S. Nilsen,

G. S. Pappalardo, W. Peryt, A. Pulvirenti, S. Radomski,

T. C. Randles, F. Riggi, P. Skowronski, R. Turrisi,

L. Vannucci, T. Virgili

Alice-ITS week Review June 7 2002 2

Outline

• Geometry

• SPD

• SDD

• SSD

• General AliRoot status.

Alice-ITS week Review June 7 2002 3

Results of GeometryReview

• SPD: only briefly looked at.

• SDD: Geometry old but ok.

• SSD: Missing two Front end cards, end ladder elements, wrong Al cooling tubes, and kapton cables. Otherwise old geometry.

• End caps and services: Old course geometry otherwise ok.

Alice-ITS week Review June 7 2002 4

Changes to GeantParameters

Sensitive Si Material -rays on, Ecut=70KeV

, Brems Ecut=70KeV

, Hadron Ecut=1MeV

None Sensitive Materials (Default Settings)

-rays off

• All Ecut=1.0MeV

For All Materials -rays on, Ecut=30KeV

-rays on, Ecut=30KeV

Ecut=1.0MeV

• Hadrons Ecut=30KeV

• Beam Pipe parameter no longer default but set like ITS.

Pre-March 2002 As of June 2002

Alice-ITS week Review June 7 2002 5

Geantes to GeantParameters cont.

Sensitive Si:• Step < 1cm /step < 1.0º• Edep/Eparticl< 30• Volume Boundary location

precision 1cm

Centeral barrel:• Step < 1cm /step < 1.0º• Edep/Eparticl< 30• Volume Boundary location

precision 1cm

Sensitive Si:• Step < 75m /step < 0.1º• Edep/Eparticl< 0.1• Volume Boundary location

precision 1m

Centeral barrel:• Step < 0.1cm /step < 0.1º• Edep/Eparticl< 0.1• Volume Boundary location

precision 1 m

Pre-March 2002 As of June 2002

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Geantes to GeantParameters cont.

Air:• Step < 1cm /step < 1.0º• Edep/Eparticl< 0.003• Volume Boundary location

precision 1cm

Services:• Step < 0.01cm /step < 10.0º• Edep/Eparticl< 0.003• Volume Boundary location

precision 0.003cm

Air:• Step < 1cm /step < 0.1º• Edep/Eparticl< 0.1• Volume Boundary location

precision 1m

Services:• Step < 1cm /step < 1.0º• Edep/Eparticl< 0.5• Volume Boundary location

precision 10 m

Pre-March 2002 As of June 2002

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Changes to Infrastructure• Old:

– Hits Digits RecPoints Tracks• Use Macros, works only for ITS, not in conjunction with other

detectors.• All new data appended to end of initial galice.root file.

• New:– Hits SDigits Digits Tracks PID– SDigits-0 + SDigits-1 Merging Digits

• Added Region of interest cut to Merging.• Merging done using a TTask, and others coming.• Hits SDigits Digits can be done for all detectors at one time (or

soon will be).• Hits, SDigits, Digits, and RecPoints can be in different files.

Alice-ITS week Review June 7 2002 8

General ITS Comments

• Fast-Point simulation getting more use than expected.

• We still need to improve, write, documentation.• Test Macros and the like are still not being

developed and disseminated.• We need to develop better simulations of Test

Beam setups, so that we can make even better comparisons with our simulations.

• ITS AlgorithmAlgorithm Review was missed. Needs to be rescheduled and presentations need improvement.

Alice-ITS week Review June 7 2002 9

SPD related studies• Multiplicity Measurement studies.• Pseudorapidity distribution studies.• Vertex Reconstruction Studies.• SPD based Trigger studies.• SPD-ZDC Correlation studies.• SPD Occupancy studies.• SPD noise studies.• Still have Two available SPD simulations

– Bari-Salerno Model (Default).– Dubna Model.

Alice-ITS week Review June 7 2002 10

Remaining SPDProblems

• The Bari-Salerno model (FORTRAN version) is used by NA57.

• The number of single pixel clusters simulated is more than seen in the Test Beam data.

• The number of 2 and more wide pixels are greatly under predicted.

Bari-SalernoDubnaTest Beam

Alice-ITS week Review June 7 2002 11

Remaining SPDProblems cont.

• Adjusting parameter of the Dubna model can compensate a bit, but leads to unphysical diffusion parameters.

• Changes to the Bari-Salerno model would require similarly unphysical asymmetric coupling parameters.

Bari-SalernoDubnaTest Beam

Alice-ITS week Review June 7 2002 12

SDDActivities

• Much work to try to speed up SDD detector simulation or at least move the slowest parts to SDigit creation.

Detector Sdigits Sec/evnt

Digits Sec/evnt

SPD 0.52 61.28

SDD (March) 114.92 46.96

SDD (new) 8.67 33.86

SSD 0.47 16.84

Based on3 p-p events

Alice-ITS week Review June 7 2002 13

SDD Timings

• The source of the slower SDD simulations are due to the need to have time correlated noise and so consequently use a FFT.

• The TPC, also should have time correlated noise, but have not implemented it yet. At present they are using Random Gaussian noise.

Alice-ITS week Review June 7 2002 14

SDD and Test Beams• Some minor discrepancies

in Anode resolution.• A systematic discrepancy in

Time resolution, may be due to a jittery start pulse in the Test Beam. Drift Path (mm)

0 5 10 15 20 25 30 350.6

0.7

0.8

0.9

1

1.1

1.2

294 um pitch detector

Beam Test DataBeam Test Simulation

Reconstruction Efficiency

0 5 10 15 20 25 30 350

20

40

60

80

100

Beam Test Simulation (Time)

294 um pitch detectorTime Resolution

Beam Test Data (Time)

Drift Path (mm)0 5 10 15 20 25 30 35

0

20

40

60

80

100

294 um pitch detectorAnode Resolution

Beam Test Data (Anode)

Beam Test Simulation (Anode)

Drift Path (mm)

Alice-ITS week Review June 7 2002 15

SDD Parameters

Based on experimental values:

Drift velocity 7.3 m/nsDiffusion constant 3.2 m2/nsInitial size of the cloud 30. mBaseline 20 ADC cntsNoise after electronic 2.38 ADC cntsNoise 10Maximum ADC value 1024 ADC cntsTime Jitter Error 20. mADC sample frequency 40. MHz

Alice-ITS week Review June 7 2002 16

SSD Remaining problems

• SSD Reconstruction needs review.– Piort Skowronski’s reconstruction need

additional comments, to allow it to be maintained, and have it’s parameters reviewed.

– Alternative Ghost and overlaping tracks algorithm needs to be investigated.

– Ghost removal by tracking needs to be implemented.

Alice-ITS week Review June 7 2002 17

SSD Remaining problemscont.

• SSD Digit-ADC histogram has unexpected shape.– See

http://www.ts.infn.it/~efragiac/doublepeak/doublepeak.html and http://AliSoft.cern.ch/people/masera/ssd/

B=0.2T, old settings

Mip peak

Digit ADC

Alice-ITS week Review June 7 2002 18

Study Continues

B=0T

B=0.2TB=0.4T

Digit ADC

Digit ADC

Digit ADC

No NoiseNo Coupling

Just charge sharing.Also seen in SDigits.

Alice-ITS week Review June 7 2002 19

Continue B=0.4

Digit ADC Digit ADCDigit ADC

Digit ADC Digit ADC Digit ADC

1 StripClusters

2 Strip

Clusters

3 Strip

Clusters

4 Strip

Clusters

5 Strip

Clusters

6 Strip

Clusters

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Continue B=0

1 Strip

Clusters

2 Strip

Clusters3 Strip

Clusters

4 Strip

Clusters

5 Strip

Clusters6 Strip

Clusters

Digit ADC

Digit ADC Digit ADC Digit ADC

Digit ADCDigit ADC

Alice-ITS week Review June 7 2002 21

NA57 Strip DataB=0

Alice-ITS week Review June 7 2002 22

NA57 DataB=1.6T

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General AliRootStatus

• Production runs to produce Hits done in Fall 2001 and Winter 2002, more scheduled.

• Big push to get all detectors producing SDigits, Digits, and RecPoints, within the same AliRoot section.

• New high level data structures, use of TFolders.• SDigit merging and writing SDigits, Digits, and

RecPoints into separate files.