PHOS offline status report

PHOS offline status report

Yuri KharlovALICE offline week

7 July 2008

Simulation

• Status of PHOS FEE is still being changed:– Simulation of PHS raw data needs flexible handles

instead of hard-coded parameters

• Physical parameters of the first PHOS module differs from the designed ones:– PHOS crystal light yield and related parameters should

be changeable without recompilation of the code

• A class AliPHOSSimParam supplies various simulation parameters to PHOS.

7 July 2008 PHOS offline status 2

Steering the simulations(as of offline week Apr-2008)

AliPHOSSimParam sets PHOS simulation parameters:

• Float_t fLightYieldMean ; // Average number of // photoelectrons per GeV

• Float_t fIntrinsicAPDEfficiency; // APD efficiency including // geometric coverage

• Float_t fLightFactor ; // Average number of photons // collected by APD per

GeV• Float_t fAPDFactor ; // factor relating light

// yield and APD response

• Float_t fAPDNoise; //RMS of APD noise• Float_t fEMCDigitThreshold ; //minimal energy to keep digit• Float_t fEMCADCchannel ; //width of ADC channel in GeV• Float_t fTOFa ; //constant term of TOF resolution• Float_t fTOFb ; //stochastic term of TOF resolut.


PHS FEE: raw data simulation

• {energy, time, id} is converted to 2 pulses as ALTRO samples, High Gain and Low Gain

• AliPHOSPulseGenerator:– Parameters of the signal shaper– Parameters of ALTRO sampling:

• Noise• Pedestal• Number of samples• Number of presamples

• Now all FEE parameters are hard coded. • Last week a necessity to change the parameters without

recompilation of the code has been realized (namely, the number of samples can vary up to 1023).

• A redesign of AliPHOSPulseGenerator will be done to provide the required flexibility.


PHOS configuration for PDC08 in Config.Cif (iPHOS) {

//=================== PHOS parameters ===========================

AliPHOS *PHOS = new AliPHOSv1("PHOS", "IHEP");

//Set simulation parameters different from the default ones.

AliPHOSSimParam* simEmc = AliPHOSSimParam::GetInstance() ;

// APD noise of warm (+20C) PHOS:

Float_t apdNoise = 0.012*2.5;

simEmc->SetAPDNoise(apdNoise);

//Raw Light Yield at +20C

simEmc->SetMeanLightYield(18800);

//ADC channel width at +18C.

simEmc->SetADCchannelW(0.0125);

}

Simulation parameters are set in Config.C. Might be better to store them in OCDB.

7 July 2008 5PHOS offline status

PHOS geometry for 2008

• One PHOS module is installed at 6 o’clock• Position of the module is measured w.r.t. the ALICE global reference

system (19.05.2008):

• An ascii table with survey data in ALICE global reference system was provided by the survey team.

• A class to convert this table to AliAlignObjAngles is ready (T.Pocheptsov). Now it is testing for consistency, overlaps, etc (G.Shabratova).

Real center Ideal center

X, mm 13 0

Y, mm -4471 -4600

Z, mm -14 0


More about geometry

• In May a request from P.C. has been passed to PHOS to provide a single PHOS module for simulations in PDC, as a geometry-as-built.

• Now the option to set an arbitrary number of modules in arbitrary configuration is provided:– AliPHOS *PHOS = new AliPHOSv1("PHOS", “PHOS3_noCPV");

– AliPHOS *PHOS = new AliPHOSv1("PHOS", “PHOS345_noCPV");

• However, we asked to leave all 5 modules for PDC08.• A few overlaps/extrusions have been discovered by

Andreas. Now fixed.


1 module at 6 o’clock


PHS raw data

• PHS raw data simulation and reconstruction did not change• Real mapping differs from the ideal one:

• Cables will not be reconnected till the end of 2008• New mapping is to be provided for reconstruction and DA:• Renaming the 4 mapping files is sufficient. It will be done as soon as

next data is taken.


Expected Equipment ID Actual Equipment ID

1800 1803

1801 1801

1802 1800

1803 1802

CPV raw data

• Now CPV raw data simulation is implemented (in svn trunk since 7 July 2008):– AliPHOSCpvRawWrite – a new class

– AliPHOS::Digits2Raw – updated for CPV raw data

• CPV mapping:– 1 CPV module is 1 DDL, total 5 CPV modules

– 1 DDL is divided into 16 row

– 1 row is 10 Dilogic chips

– 1 Dilogic ship is 48 (=6x8) pads

• In total, 7680 pads per module

• Reconstruction of CPV raw data will come next


On-line processing

• Two DA are implemented:– Relative gain equalization by mean deposited energy and HG/LG ratio

(PHOSGAINda.cxx)– Bad channel map

• The algorithmic code for DAQ DA and HLT DA is identical– AliPHOSRcuDA1– AliPHOSDA2

• The histograms produced by DAQ DA and HLT DA are identical and scalable– due to per-RCU parallelization of DA in HLT, each process produced

histograms for ¼ of PHOS module.• DA is embedded to DAQ and HLT environments: data reading and

decoding are different.• There is only one preprocessor for all DAs, independent on

HLT/DAQ environment


DA deployment in DAQ

• PHOSGAINda is deployed in P2 on the DQM DAQ machine

• DA processes data from PHYSICS and STANDALONE runs

• This DA is permanently running for taken data in P2

• PHOS still runs stand-alone, therefore Shuttle does not pick up DA’s histograms


PHOS HLT at P2

• PHOS HLT is fully operational at P2– Basic chain providing on-line monitoring running

without a single stop for a week


Zero Suppression in HLT

• Software “zero suppression” possible in HLT– Not on a sample level at this point, behaving more

like a sparse scan– Possible to implement on sample level if needed


HLT Reconstruction

• Energy and timing extraction • Clustering for HLT has been implemented

– Based on the algorithm used by off-line

• Most of the off-line reconstruction has been ported to HLT during the last weeks– Not been sufficiently tested and debugged


PHOS HLT DA

• Running on HLT using same code as off-line • Porting of offline code provides possibility to do

more advanced physics calibration• Needs more testing with the FXS


HLT On-line Monitoring

• Using PHOS HLT Online Monitoring used for debugging and visualisation

• Integration into AliEVE started (first version routinely used)

• With new ported reconstruction better visualisation and performance monitoring is possible


HLT On-line Monitoring


About DCS DP• A set of DCS DPs which are potentially useful for offline reconstruction was

submitted to the Shuttle team a year ago• No correction of calibration parameters is expected for DCS DPs. The DCS

DPs might be useful (but not mandatory) to see for reference, if some unexpected data appears.

• PHOS PVSS is being integrated in P2 with very little manpower (0.25 FTE). No DCS DPs are monitored, nor archived at the moment.

• Shuttle looks for declared DPs, does not find them and stops any actions of the PHOS preprocessor.

• Due to missing DCS DPs, the DAQ DA and HLT DA are not validated yet.• In SVN trunk, AliPHOSPreprocessor::ProcessDCS() returns kFALSE• AliPHOSPreprocessor::ProcessDCS() can check the existence of DPs which

provides more flexibility.• PHOS can survive without DCS preprocessor (this year).


Reconstruction parameters

• The framework for detector reconstruction parameters is being developed (Cvetan)

• AliPHOSRecoParam is inherited from AliDetectorRecoParam. EMC and CPV reco parameters were merged into one object

• All PHOS code has been changed to follow the reco parameters framework. Submitted to Cvetan.

• Validation will be performed after committing the framework to CVN.


QA

• QA histograms are filled at every step of simulation and reconstruction:– Hits– Digitization– Raw data– Local reconstruction– ESD filling

• So far the quality is checked “by eyes”. No quantitative criteria is provided yet. No reference objects are created nor stored in OCDB


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PHOS offline status report