Contact : M.Asai (SLAC)

Introduction

This example demonstrates how to connect the information between primary particles and hits. It also utilize some user-information classes.

Geometry and region information

It has a quite simple cylindrical tracker of 5 layers and a cylindrical calorimeter of lead and scintillator. Dedicated regions are assigned to both tracker and calorimeter mother volumes not for setting additional production thresholds but for adding some more information to these regions. RE01RegionInformation is the class for this purpose. A "readout geometry" is attached to the calorimeter to define its cells.

Physics

This example basically uses QGSP_BERT physics list. In addition to this, RE01UnknownDecayPhysics is used for adding decay process to G4UnknownParticle.

Event generator

An event sample is attached. This event has a Higgs particle which decays into e+e- and mu+mu- pairs through two Z bosons. It uses G4HEPEvtInterface. In this example, by utilizing G4UnknownParticle, all particles appear in the primary event are converted to G4Track and then to RE01Trajectory. Relation between primary particles and track IDs are shown at the end of event execution.

"Source track" information

"Source track" is meant for a track that is either a primary particle or a track born is the tracking region. This information is stored in RE01TrackInformation class object and copied from a parent track to its daughters.

Track suspension

All source tracks are suspended for their tracking when they are getting into the calorimeter region. Thus, all tracks in the tracker region are tracked before generating any shower in the calorimeter.

Tracker hits associated with primary particle information

Information kept in RE01TrackInformation is used to connect each tracker hit to the primary particle.

Energy deposition of each source track

Utilizing RE01StackingAction, shower generation is done for each souorce track separately, and thus energy deposition in calorimeter cells are shown for each individual source track. With the trajectory information, energy deposition for each primary particle can also be gotten.