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NEXT : G4 Optical Step Collection¶

Objective¶

CG4 steered simulation running from GDML geometry with natural optical steps propagated with Opticks (using OpticksMgr) and hits passed back to CG4

Stages¶

Revisit optical step collection within cfg4-, add natural collection of both Cerenkov and Scintillation process steps into one buffer
The OpticksMgr integration will need to happen in new package okg4- but the G4 level step collection can be developed first with cfg4- and tested on genstep file basis with OpticksMgrTest
generalize genstep material code mapping/lookup

Review old collection with G4DAEChroma¶

http://simoncblyth.bitbucket.org/env/notes/chroma/G4DAEChroma/
gdc- developed in ~/env/chroma/G4DAEChroma
some version was copied into Dayabay NuWa svn Utilities
Tao also integrated some version into JUNO ~/offline/Simulation/DetSimV2/G4DAEChroma
expect should be straightforward enough to incorporate into Opticks cfg4- ?

G4DAEChroma Observations¶

was developed in an earlier (more complicated) era when was using python Chroma, so had to handle distributed operation over ZMQ, metadata, database !
had not settled on step transport
much of gdc- array handling, serialization is obsolete, now that have opticks npy-/NPY and lots of experience using it
yuck : even some ROOT TObject serialization stuff in G4DAEChromaPhotonList which is totally obsolete
gdc- is half the story, see also csa-

csa- originally named after ChromaStackAction, but now handles DetSimChroma¶

Was intended to be renamed dsc- for DetSimChroma but that never happened.

sources in ~/env/nuwa/detsim/src
DsChromaG4Scintillation.cc

G4DAEChroma Things to plunder : looks like very little, NPY handles most of it¶

G4 workflow : G4DAEChroma::BeginOfRun EndOfRun BeginOfEvent ...
G4DAESensDet::MakeTrojanSensDet G4 trojan SD to sneak hits into G4 hit collections en-masse

Approach to reviving optical step collection¶

raid G4DAEChroma for the minimum necessary amount of code to do optical step collection within a new class for this OpticksG4Collector in opticks cfg4-
- initially avoid all the bells and whistles, no ZMQ, no metadata, no database, ... that complexity can hopefully be totally avoided with the C++ opticks

DONE : Near Standard G4 Scintillation/Cerenkov Step Collection¶

Test with:

op --tcfg4 --g4gun
CG4Test --g4gun       ## same as above

TODO: details of scintillation generation, compare Opticks vs G4 generated distrib¶