Problem 626

Summary: Change to delta ray production bookkeeping in hLowEnergyIonisation?
Product: Geant4 Reporter: marcus.h.mendenhall
Component: processes/electromagnetic/lowenergyAssignee: Vladimir.Ivantchenko
Status: RESOLVED INVALID    
Severity: enhancement CC: robert.a.weller
Priority: P2    
Version: 6.1   
Hardware: All   
OS: All   

Description marcus.h.mendenhall 2004-05-18 10:12:52 CEST 
While poking aorund in hLowEnergyIomnisation, I noticed that the energy produced by delta ray
production in the PostStepDoIt process is added to the energy deposited along the step in the
AlongStepDoIt process.  Since the along-step deposition nominally contains the correct, complete
dEdx, this results in an increase in energy loss when delta ray production is allowed (and a variation in
elenrgy loss as a function of the range cuts).

Would it be completely crazy to balance these effects, simply by recording a _negative_ deposited
energy
in the PostStepDoIt for this process, equal to the energy of the produced delta ray? Since the energy
accounted for by the delta ray is really taken from the pool of total dEdx, this would result in a zero-
sum balance between these two processes.  Since the energy will eventually get properly deposited,
when the delta ray is stopped, I think it does the right thing.

Any thoughts?

Marcus Mendenhall
Comment 1 Maria.Grazia.Pia 2004-05-18 10:16:59 CEST 
The problem is re-assigned to the developer expert in Ge4hLowEnergyIonisation.
Once more, thanks for your careful investigation of Geant4 LowE processes.

Best wishes,
Maria Grazia
Comment 2 Vladimir.Ivantchenko 2004-06-03 04:29:59 CEST 
The problem is connected with wrong interaction between multiple scattering and
G4hLowEnergyIonisation. It is fixed and fix is submitted for 6.2 release of
Geant4
Comment 3 Vladimir.Ivantchenko 2004-06-03 04:42:59 CEST 
Energy deposition PostStep is not added to energy deposition Along Step. Post
Step energy deposition is proposed to ParticleChange as a local deposition in
this point and G4 kernel is taking care about. There are no energy
non-conservation reported, so report is invalid.