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The reconstruction is implemented within the HPS Java project as a chain of org.lcsim Drivers (event processors) described by lcsim xml and run by the lcsim job manager. The EvioToLcio command line tool is used to convert the EVIO to LCIO events using an LCSimEventBuilder such as LCSimEngRunEventBuilder. The LCIO events are accessed in Java code through the EventHeader API. The Drivers add output collections to the event such as tracks, calorimeter clusters, reconstructed particles and vertices. The combined data/physics LCIO events are written out to an LCIO file, which can subsequently be converted to ROOT DST Data Format. The LCIO events may also be loaded back into the HPS Java environment for analysis.

Basic Steps

These are the steps performed in reconstructing the data:

EvioToLcio command line tool is run with command line parameters like the EVIO file(s) and the path to the XML steering file.
The JobControlManager loads the steering file which defines the chain of reconstruction Drivers and their parameters.
Detector Conditions including per channel calibrations are read and applied in Driver detectorChanged methods.
Each EvioEvent is read with EvioReader and converted to an LCIO raw data event using an appropriate LCSimEventBuilder.
The HPS Java reconstruction runs on the LCIO event, adding additional reconstruction collections to the events.
The events are written to an LCIO file containing the results of the recon.
The output LCIO file is converted to ROOT DST Data Format for analysis.

Steps 1-7 6 are typically performed in the same job using the EvioToLcio command line utility.

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Order	Driver Name	Driver Class	Description
1	RfFitter	RfFitterDriver	converts accelerator's RF wave form to time and inserts into event
2	EcalRunningPedestal	EcalRunningPedestalDriver	calculates per channel running averages for ECal signal pedestals
3	EcalRawConverter	EcalRawConverterDriver	converts ECal digits to CalorimeterHit collection with energy and time measurements
4	ReconClusterer	ReconClusterDriver	performs calorimeter clustering algorithm on ECal hits
5	CopyCollection	CopyClusterCollectionDriver	copies calorimeter clusters to new collection to preserve uncorrected energy measurements
6	RawTrackerHitSensorSetup	RawTrackerHitSensorSetup	assigns RawTrackerHits to their sensors for use by track recon
7	RawTrackerHitFitterDriver	RawTrackerHitFitterDriver	fits ADC vs time signal and stores the results, associated to the each raw hit
8	TrackerHitDriver	DataTrackerHitDriver	creates stereo pairs from SVT strip hits
9	HelicalTrackHitDriver	HelicalTrackHitDriver	creates 3D hit clusters from stereo pairs
10	TrackReconSeed345Conf2Extd16	TrackerReconDriver	track finding using layers 3, 4 & 5 as a seed, layer 2 to confirm, and layers 1 and 6 to extend
11	TrackReconSeed456Conf3Extd21	TrackerReconDriver	track finding using layers 4, 5 & 6 as a seed, layer 3 to confirm, and layers 2 and 1 to extend
12	TrackReconSeed123Conf4Extd56	TrackerReconDriver	track finding using layers 1, 2 & 3 as a seed, layer 4 to confirm, and layers 5 and 6 to extend
13	TrackReconSeed123Conf5Extd46	TrackerReconDriver	track finding using layers 1, 2 & 3 as a seed, layer 5 to confirm, and layers 4 and 6 to extend
14	MergeTrackCollections	MergeTrackCollections	merges collections from track finding into a single output collection
15	GBLRefitterDriver	GBLRefitterDriver	performs GBL track refit
16	TrackDataDriver	TrackDataDriver	adds additional collections containing track information to the output event
17	ReconParticleDriver	HpsReconParticleDriver	creates output reconstructed particle collections, associating tracks with clusters also performs vertex reconstruction and creates vertex collection
18	LCIOWriter	LCIODriver	writes output LCIO file
19	CleanupDriver	ReadoutCleanupDriver	cleans up readout state for next event (clears assignments of SVT raw hits to sensors)

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HPS Java Reconstruction Packages

The The HPS Java Documentation can be used to browse the packages and classes used for physics reconstruction.

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Old Version 94

New Version 95

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Basic Steps