2152 – The energy of GenericIon increases infinitely.

Problem 2152 - The energy of GenericIon increases infinitely.

Summary: The energy of GenericIon increases infinitely.

Status:	RESOLVED FIXED

Alias:	None

Product:	Geant4
Classification:	Unclassified
Component:	processes/electromagnetic (show other problems)
Version:	10.4
Hardware:	PC Linux

Importance:	P4 major
Assignee:	Vladimir.Ivantchenko

URL:

Depends on:
Blocks:

Reported:	2019-03-18 09:36 CET by jhlee_987
Modified:	2019-04-12 17:10 CEST (History)
CC List:	1 user (show)

See Also:

Attachments
simple geant4 code based on example B1 to show energy divergence. (140.00 KB, application/x-tar) 2019-03-18 09:36 CET, jhlee_987	Details
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Description jhlee_987 2019-03-18 09:36:12 CET

Created attachment 555 [details]
simple geant4 code based on example B1 to show energy divergence.

I have found that the kinetic energy increases infinitely when the GenericIon is set as the primary particle in single scattering process.

The attached file is a code based on Example B1, using GeneralParticleSource to set the GenericIon as the primary particle, and to output the position and energy every step.

Files changed in B1:
  exampleB1.cc
  myPhysicsList.hh (added)
  myPhysicsList.cc (added)
  B1SteppingAction.cc
  run1.mac
  B1PrimaryGeneratorAction.cc
  B1PrimaryGeneratorAction.hh
  B1RunAction.cc

The changes are marked as
//************************

//*******************

I did the following.
  (cmake)
  (make)
  ./exampleB1
  /control/execute run1.mac

I used G4EmStandardPhysicsSS in myPhysicsList, but in fact it uses G4IonCoulombScatteringModel via G4CoulombScattering, so the problem seems to be in the G4IonCoulombScatteringModel.

Comment 1 Vladimir.Ivantchenko 2019-04-08 20:04:56 CEST

Hi Daren,

thanks for this BR - it was non-trivial precision loss in computation of particle momentum. The fix is proposed for testing and will be submitted for the patch.

Vladimir

Comment 2 Daren Sawkey 2019-04-12 17:10:20 CEST

Thanks to jhlee.