Dead and noisy channels masking

General description

There are some channels that don't work properly. Generally we can divide this channels into two groups:

• dead channels (do not answer)
• noisy channels (answer to much)

The purpose of dead and noisy channels masking is to exclude both groups of channels from simulation and reconstruction.

Steps that have to be taken

Out of software:

• retrieve list of dead and noisy channels
• convert this list to XML file

In Software:

• parse XML file and create AnalysisMask
• use AnalysisMask in order to exclude channels from simulation and reconstruction

The software part of dead and noisy channels masking takes place during digitalization.

Common part for every detectors

parse XML file and create AnalysisMask

This step of masking takes part directly in software. In order to parse XML and create AnalysisMask(TotemCondFormats/DAQInformation/interface/AnalysisMask.h) we should use DAQMappingSourceXML class (TotemCondFormats/DAQInformation/plugins/DAQMappingSourceXML.cc). To use this class we have to include in our configuration file a special module. We have to also provide mapping files and XML files containing dead & noisy channels. Sample configuration files will be later presented in this document.

Roman Pots

retrieve list of dead and noisy channels

The list of dead and noisy channels can be obtained by using extract_vfat_channels script written by Dominik Mierzejewski. The description of this script can be found at https://twiki.cern.ch/twiki/bin/view/TOTEM/CompComTools.

convert this list to XML file

To convert this list to XML file we can use deadChannelsToXML.py which is described at https://twiki.cern.ch/twiki/bin/view/TOTEM/CompComTools.

use AnalysisMask in order to exclude channels from simulation and reconstruction

To exclude channels from simulation or reconstruction we have to simply check whether an AnalysisMask contains this channels and then (if it is true) remove this channels from vector (or sth similar) of channels. For Roman Pots it is done in:

Reconstruction:

In class TotemRawData (TotemRawData/RawToDigi/plugins/Raw2DigiProducer.cc) in method rpDataProduce

Simulation:

In class RPDigiProducer (SimTotem/RPDigiProducer/src/RPDigiProducer.cc)

• reading AnalysisMask

In method beginJob (after software migration it is very likely that this method will change to beginRun)

• removing dead and noisy channels

In method produce, using DeadChannelsManager (SimTotem/RPDigiProducer/src/DeadChannelsManager.cc)

Sample configuration file

In reconstruction dead and noisy channels are always excluded. However in simulation it is not necessary, hence a special flag indicating whether we want to simulate dead channels or not was introduced. A sample configuration file can be found in the repository: TotemCondFormats/DAQInformation/test/prodRPinelastic90Energy7TeV_cfg_withDeadChannels.py .

The new part is:

process.load('TotemCondFormats.DAQInformation.DAQMappingSourceXML_cfi')

# mapping files
process.DAQMappingSourceXML.mappingFileNames.append('TotemCondFormats/DAQInformation/data/rp_220.xml') #load all mapping files
process.DAQMappingSourceXML.mappingFileNames.append('TotemCondFormats/DAQInformation/data/rp_147.xml')
process.DAQMappingSourceXML.mappingFileNames.append('TotemCondFormats/DAQInformation/data/t1_all.xml')
process.DAQMappingSourceXML.mappingFileNames.append('TotemCondFormats/DAQInformation/data/t2_4quarters.xml')

# mask files
process.DAQMappingSourceXML.maskFileNames.append('TotemCondFormats/DAQInformation/data/deadChannels_220.xml') #load configuration files
process.DAQMappingSourceXML.maskFileNames.append('TotemCondFormats/DAQInformation/data/deadChannels_147.xml') #for both stations

process.RPSiDetDigitizer.simulateDeadChannels = cms.bool(True) #this flag (set to true) indicates that we want to take 
                                                               #into account dead channels

NOTE

If you need more specific documentation, please look into source code of class mentioned in this documentation. Important parts of the code are documented in the repository.

NOTE2

All scripts presented in this section (extract_vfat_channels, deadChannelsToXML.py) works only for Roman Pots.

-- JakubSmajek - 02-Sep-2011

T1 detector

retrieve raw list of dead and noisy channels

The list of dead and noisy channels can be obtained by using T1DeadChannelAnalyzer that is similar to T1XMLDataDigiProducer. T1DeadChannelAnalyzer count hits per channel and saves it in the map: encoded_channel_number -> number_of_hits. where:

encoded_channel_number  = 1000000 * arm + 100000 * plane + 10000 * chamber + 1000 * channelType + channelNumber; 

You can run T1DeadChannelAnalyzer using sample configuration file:

import FWCore.ParameterSet.Config as cms
process = cms.Process("T1ChannelsHitRate")
process.maxEvents = cms.untracked.PSet(
    input = cms.untracked.int32(NUMBER_OF_EVENTS)
)
process.load("Configuration.TotemCommon.LoggerMin_cfi")
# raw data source
process.source = cms.Source("RawDataSource",
    verbosity = cms.untracked.uint32(0),
    eventsToCheck = cms.uint32(10),
    skipCorruptedEvents = cms.bool(False),
    performChecks = cms.bool(True), 
    setRunNumberFromFileName=cms.bool(False),    
    fileNames = cms.untracked.vstring('PATH_TO_RAW_DATA')
)
process.DAQInformationSourceXML = cms.ESSource("DAQInformationSourceXML",
    xmlFileName = cms.string('TotemRawData/RawToDigi/python/T1_all_0.xml')
)
process.t1raw2digi = cms.EDAnalyzer("T1DeadChannelDataAnalyzer",
                                    verbosity = cms.untracked.uint32(0),
                                    deadCutValue= cms.untracked.uint32(150),
                                    noiseCutValue= cms.untracked.uint32(10),
)
process.o1 = cms.OutputModule("PoolOutputModule",
    fileName = cms.untracked.string('./recoT1_091101_mux.root'),
    outputCommands=cms.untracked.vstring('drop totemRawEvent_*_*_*')
)
process.p1 = cms.Path(process.t1raw2digi)
process.outpath = cms.EndPath(process.o1)

it is advised to set NUMBER_OF_EVENTS > 10 000.

deadCutValue and noiseCutValue is used when checking if channel is dead or noisy. By default deadCutValue = 200 and noiseCutValue = 9.

it means that channel is considered dead if it's hits number is less or equal than average_number_of_hits_per_channel_in_plane / deadCutValue

channel is considered as noisy when it's hits number is greater or equal then average_number_of_hits_per_channel_in_plane * noiseCutValue

At the end of processing all channels that are considered dead or noisy are printed.

The output has format:

arm:plane:chamber:channel_type:channel_number

Example:

$ cmsRun T1DeadChannelAnalyzer_runner.py > rawDeadChannelsList.txt

Create XML file with dead and noisy channels

rawDeadChannelsList.txt has to be changed to XML file. To do that i wrote T1RawDeadChannelsToXML.py that parse rawDeadChannelsList.txt file and prints xml format file - T1DeadChannelsList.xml

to run it:

$ python T1RawDeadChannelsToXML.py    rawDeadChannelsList.txt     >    T1DeadChannelsList.xml 

XML file format:

<top>
    <t1_detector_set id="100">
        <t1_arm id="0">
            <t1_plane id="1">
                <t1_csc id="2">
                    <t1_channel_type id="1" full_mask="no">
                        <channel id="44"/>
                        <channel id="55"/>
                    </t1_channel_type>
                    <t1_channel_type id="2" full_mask="yes"/>                                  
                    <t1_channel_type id="3" full_mask="no">
                        <channel id="220"/>
                        <channel id="129"/>
                    </t1_channel_type>
                </t1_csc>
            </t1_plane>
        </t1_arm>
    </t1_detector_set>
</top> 

Chart presenting number of hits per channel in T1 detector

• T1ChannelsHitRate:
  

use AnalysisMask in order to exclude channels from simulation and reconstruction

To exclude channels from simulation or reconstruction we have to simply check whether an AnalysisMask contains this channels and then (if it is true) skip operation. For T1 it is done in:

Reconstruction:

In class (TotemRawData/RawToDigi/plugins/Raw2DigiProducer.cc) in method T1DataProduce

Simulation:

In classes:

T1DigiProducer (SimTotem/T1DigiProducer/src/T1DigiProducer.cc)

T1Digitizer (SimTotem/T1DigiProducer/src/T1Digitizer.cc)

T1WireElectronicsSim (SimTotem/T1DigiProducer/src/T1WireElectronicsSim.cc)

T1StripElectronicsSimStandard (SimTotem/T1DigiProducer/src/T1StripElectronicsSimStandard.cc)

T1StripElectronicsSimVfat (SimTotem/T1DigiProducer/src/T1StripElectronicsSimVfat.cc)

• reading AnalysisMask

In method beginJob of T1DigiProducer (after software migration it is very likely that this method will change to beginRun)

• removing dead and noisy channels

In method produce, using T1DeadChannelsManager (SimTotem/T1DigiProducer/src/T1DeadChannelsManager.cc)

Sample configuration file

In reconstruction dead and noisy channels are always excluded. However in simulation it is not necessary, hence a special flag indicating whether we want to simulate dead channels or not was introduced.

The new part is:

process.load('TotemCondFormats.DAQInformation.DAQMappingSourceXML_cfi')

# mask files
process.DAQMappingSourceXML.maskFileNames.append('PATH_TO_T1_DEAD_CHANNEL_LIST')  #load configuration files
process.T1Digis.simulateDeadChannels = cms.bool(True) #this flag (set to true) indicates that we want to take dead channels into account. 

-- MarcinBorratynski - 08-Sep-2011