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Detector Algorithm Quality Assurance Experience with cosmic ray data taking Reconstruction Alignment
PMD Software Status
Outline
ALICE offline week, CERNAjay Kumar Dash For the PMD
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Raw Data
Pedestal
ESD
Hits
SDigits
Digits
Clustering
Simulation
keV-ADC Conversion From Test Beam
Hardware Mapping information
Flow chart of Simulation & Reconstruction for PMD
2003 and 2006 Test Beams
Gain
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Detector Algorithm (DA)
Two algorithms for PMD
Pedestal DA: Calculates Mean, RMS for each channel No of Events : 1K (to have a better mean and sigma) Mode of data taking : Standalone, LDC
Gain DA : Calculates relative gain of each channel No of events : ~10 Million Execute on monitoring machine
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DA continuing…..
Pedestal DA
pedestal2304.pedpedestal2305.pedpedestal2306.pedpedestal2307.pedpedestal2308.pedpedestal2309.ped
===>>Load to MARC for zero- suppression
ASCII files
PMD_PED.root ==>> File Exchange Server (FES) ==>> OCDB
Copy stored to DAQ DataBase for GAIN DA
Stores mean and rms for
each channel
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Pedestal run No : 42155
DA continuing…..
One entry corresponds to one channel
rms (adc)mean (adc)
coun
ts
coun
ts
X
Y
Preshower plane
Modules installed for pp run
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Lessons from Pedestal Analysis
In the beginning, we were unable to read pedestal raw file Found few bugs in the decoding algorithm
Fixed AliPMDRawStream class Now successfully read the pedestal data as well as simulated RAW data
RAW data writing class “AliPMDDDLRawData” is modified appropriately
Codes are committed to SVN
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Both plane
adc
From SimulationPYTHIA Minimum bias20K eventsSqrt(S) = 14 TeV
Isolated adc spectra
DA continuing…..
0
0 0
0
0
0ADC>0
isolated cell
Cell to cell gain calibration
Philosophy
Mimics the single particle muon
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GAIN DA
Minimum entries required : ~ 1k per channel Total # channels : 221184 Total entries required for stable mean ( or MPV) : ~220 Million
Simulation:
PYTHIA Minimum bias @ Sqrt(S) = 14 TeV 20K events => ~ 0.5 Million Entries No of events required : ~ 10 Million pp events
Single particle 1GeV muon
DA continuing…..
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• One RUN may not be enough to give the required statistics• Need to combine few RUNS
PMD_GAIN_CONFIGFILE(status = 0 Event = 0 MaxEvent )
PMD_PED.root
Event processed >= Max Event
WritePMD_GAIN.root
FES
Change CONFIGFILE (0, 0, MaxEvt)
Write a temp filepmd_gain_tempfile.datChange PMD_GAIN_CONFIGFILE
(1, Evt processed, MaxEvt)
Fetches PMD_GAIN_CONFIGFILE
PMD_PED.root
Does pedestal sub
Isolated cellsearch
False
True
DAQ Data Base
GAIN DA
DA continuing…..
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Quality Assurance
• Hits• Sdigits• Digits• Raw data• Reconstruction• ESD
Implemented at various levels
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Hits Level QA
energy deposition (eV)total hits in preshower plane
cou
nts
cou
nts
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Digits Level QA
total # of cells hit cell adc
cou
nts co
un
ts
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Raw Level QA
Total cell adc
To
tal #
of c
ells
Cell adc
cou
nts
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Reconstruction Level QA
cluster adc# of clusters in 6 modules
cou
nts
cou
nts
• QA histos are also filled for ESD
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• Some preliminary histos are defined in the codes and committed to SVN
• In some histos, scales are not proper
• Also discussing what are the histos to be put
• By the end of this week the final code will be committed as well as the reference histos
Status of QA
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Experience with Cosmic data taking
PMD was included in the Cosmic run
Cosmic data are being analysed
For PMD, it was basically random coincidence
But it was a good experience in debugging the reconstruction software as well as to come across some hardware problem
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Run no : 42290
Experience with cosmic …..
Plots are after pedestal subtraction (Only for one event)
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Lesson from Cosmic
For corrupted event PMD reconstruction was crashing Sometime the FEE board address was wrong in cosmic run, but the pedestals are coming alright. No FEE board address found to be wrong
This problem is under investigation
Remedy
Put protection against the corrupt data in AliPMDRawStream, AliPMDClusterFinder
Modification inside AliPMDClusterFinder to do the reconstruction for active modules
All modified codes are in SVN
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Reconstruction
Clustering is the main algorithm for PMD reco
In the old clustering algorithm, there are many static dimensions
Everything was cleaned up and made dynamic memory allocation
The code is under the test using the simulated Pythia events
Will be committed by the end of this week
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For Photons
inc Eta of incident photonclus Eta of cluster centre
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inc Phi of incident photonclus Phi of cluster
For Photons
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Macro to generate the Alignment object and to read the survey data points are in SVN
Alignment
Once the detector fiducial points are surveyed, we can immediately generate the misalignment object