marlintpc::ChargeDistributionProcessor Class Reference

This processor takes the coordinates of the drifted electrons and the charge from amplification and smears the charge on the padplane. More...

#include <ChargeDistributionProcessor.h>

Inheritance diagram for marlintpc::ChargeDistributionProcessor:

Public Member Functions
virtual Processor *	newProcessor ()
virtual void	init ()
	Called at the begin of the job before anything is read. More...
virtual void	processRunHeader (lcio::LCRunHeader *run)
	Called for every run.
virtual void	processEvent (lcio::LCEvent *evt)
	Called for every event - the working horse.

Static Public Member Functions
static std::list< std::pair < VoxelTPC::VoxelIndex, int > > *	fetchVoxelList ()
	A function to directly get the voxels from the internal map. More...

Protected Attributes
std::string	_inputCollectionName
	Input/output collection names. More...
std::string	_outputCollectionName
	Name of the output collection.
std::string	_tpcConditionsColName
	Name of collection containing the TPCConditions.
std::string	_altTPCConditionsName
	Name of the newly created TPCConditonsCollection if the original one is not writeable.
std::string	_gas
	Name of the gas mixture.
float	_ETrans1
	First transfer field.
float	_ETrans2
	Second transfer field.
float	_EInd
	Induction field.
bool	_outputIsPersistent
double	_sigma
	If true the output collection is written. More...
double	_sigmaLong
	Value of the longitudinal defocussing.
float	_BField
	Strength of the magnetic field in T.
double	_bunchIntervall
	Time between two bunch crossings in ns.
double	_zBinLength
	Length of a z-bin in ns.
int	_writeAfterNEvents
	Number of overlayed events after which the TPC is read out.
const gear::TPCParameters *	_tpcParameters
marlintpc::VoxelTPC *	_trackerData
bool	_isFirstEvent
	Test if this is the first event to be processed at all.
double	_ionisationEnergy
	Ionisation energy of the gas.
bool	_improveMemoryFootprint
	Flag whether to use the memory saving shotcut.
double	_sigmaOverride
	Optional override parameter for the charge broadening.
double	_BOverride
	Optional override parameter for the magnetic field.
double	_inductionFactor
	Size of induction on neighbour pads in percent of charge on central pad.

Static Protected Attributes
static std::list< std::pair < VoxelTPC::VoxelIndex, int > > *	_fetchedList = 0
	A subset of voxels which has been removed (fetched) from the VoxelTPC. More...

Detailed Description

This processor takes the coordinates of the drifted electrons and the charge from amplification and smears the charge on the padplane.

Broadening of the charge cloud due to diffussion between the GEMs is included as well as charge transfer parameters in dependence on the GEM settings. The processor adds the transversale defocussing in the GEM stack to the conditions data. If the conditions data is write protected and therefor the defocussing can not be added a new writeable TPCConditions object is added to the data stream. The new object is a copy of the original TPCConditions and additionally holds the value for the mean amplification of an single electron. Later processors should only use the newly created object.

Do not use the marlin::ConditionsProcessor to manage TPCConditions set or modified by the GEMProcessor!!!

The WriteAfterNEvents parameter is optional. It is inteded for a CLIC-like bunch train structure where the bunch train length is much shorter than the readout time of the TPC. The TPC is read out completely if ( eventNr % WriteAfterNEvents == (WriteAfterNEvents - 1) ). All events up to this point are empty, the whole TPC picture is written to one event.

The ImproveMemoryFootprint flag disables the output collection. Instead the static fetchVoxelMap() function has to be called by the subsequent processors.

Input - Prerequisites

Collection of SimTrackerHits with charge values set as dEdx

Output

Collection with TPCVoxels containing charges on pads

Parameters

InputCollectionName	Name of input collection, SimTrackerHits
OutputCollectionName	Name of output collection, TPCVoxel
WriteOutputToStorage	If true the output collection is written (default: true)",
xBinLength	Length of the bins in z direction in ns
ETrans1	Value of first transfer field in V/cm
ETrans2	Value of second transfer field in V/cm
EInd	Value of Induction field in V/cm
Gas	Gas mixture
BunchIntervall	Time between two bunch crossings in ns
TPCConditions	Name of the collection with TPCConditons to be read in
AlternativeTPCConditionsName	Name of newly created TPCCondtions collection if original object is writeable
IonisationEnergy	Mean ionisation energy of the chambers gas in [GeV] (default: 26E-9 (argon))
WriteAfterNEvents	Force readout of the full TPC after overlaying n events (optional)
ImproveMemoryFootprint	Flag whether to use fetchVoxelCollection instead of the output collection (default:false)
SigmaOverride	Override the sigma which usually is calculated from the diffusion in the GEM stack (optional)

Author

Thorsten Krautscheid

Member Function Documentation

std::list< std::pair< VoxelTPC::VoxelIndex, int > > * marlintpc::ChargeDistributionProcessor::fetchVoxelList ( )

static

A function to directly get the voxels from the internal map.

Like this the data does not go to the event and thus reduces the memory footprint. Sort of a hack which bypasses the processor interface, but necessary due to the huge memory consumption. Make sure to delete it in order not to leak memory.

References _fetchedList.

Referenced by marlintpc::TPCElectronicsProcessor::processEvent().

void marlintpc::ChargeDistributionProcessor::init ( )

virtual

Called at the begin of the job before anything is read.

Use to initialize the processor, e.g. book histograms.

References _BField, _BOverride, _EInd, _ETrans1, _ETrans2, _gas, _inductionFactor, _isFirstEvent, _sigma, _sigmaLong, _sigmaOverride, _zBinLength, marlintpc::TPCGas::CalculateGasParameters(), marlintpc::TPCGas::GetLongitudinalDiffusion(), marlintpc::TPCGas::GetTransverseDiffusion(), marlintpc::TPCGas::SetBField(), and marlintpc::TPCGas::SetEField().

Member Data Documentation

std::list< std::pair< VoxelTPC::VoxelIndex, int > > * marlintpc::ChargeDistributionProcessor::_fetchedList = 0

staticprotected

A subset of voxels which has been removed (fetched) from the VoxelTPC.

It is to be fetched by the subsequent processor using fetchVoxelList.

Referenced by fetchVoxelList(), and processEvent().

std::string marlintpc::ChargeDistributionProcessor::_inputCollectionName

protected

Input/output collection names.

Name of the input collection

Referenced by processEvent().

double marlintpc::ChargeDistributionProcessor::_sigma

protected

If true the output collection is written.

Value of the transverse defocussing

Referenced by init(), and processEvent().

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The documentation for this class was generated from the following files:

• ChargeDistributionProcessor.h
• ChargeDistributionProcessor.cc