Problem 1428

Summary:	Ion Ionization process gives wrong electric charge
Product:	Geant4	Reporter:	michel.maire
Component:	processes/electromagnetic	Assignee:	Vladimir.Ivantchenko
Status:	RESOLVED INVALID
Severity:	normal	CC:	kurasige
Priority:	P5
Version:	other
Hardware:	All
OS:	All

Description michel.maire 2013-01-18 18:48:17 CET

An ion, defined in neutral atomic state (Q=0), is still deviated in magnetic field

Comment 1 kurasige 2013-01-19 02:14:35 CET

 I can not reproduce it. I tested N03 with following macro. In the run#0, O16 with Q=0 goes straight. In run#1,2, O16 with Q=1,8 is bent because of magnetic field.

/N03/det/setField 10.0 tesla
/gun/energy 10 MeV
/gun/direction 1.0 0.0 0.0

/gun/particle ion
/gun/ion 8 16 0
/run/beamOn 1

/gun/ion 8 16 1
/run/beamOn 1

/gun/ion 8 16 8
/run/beamOn 1

##Run 0 Q=0
*********************************************************************
* G4Track Information:   Particle = O16[0.0],   Track ID = 1
*********************************************************************
Step#      X         Y         Z        KineE     Volume     Process
    0     -9 cm      0 fm      0 fm     10 MeV    World   initStep
    1   -7.5 cm      0 fm      0 fm     10 MeV    World   Transportation
    2   -7.5 cm  -1.15 Ang     0 fm      0 eV     Lead      ionIoni

##Run 1 Q=1
*********************************************************************
* G4Track Information:   Particle = O16[0.0],   Track ID = 1
*********************************************************************
Step#      X         Y         Z        KineE     Volume     Process
    0     -9 cm      0 fm      0 fm     10 MeV    World   initStep
    1   -7.5 cm   -619 um      0 fm     10 MeV    World   Transportation
    2   -7.5 cm   -620 um      0 fm      0 eV     Lead      ionIoni

##Run 2 Q=8
*********************************************************************
* G4Track Information:   Particle = O16[0.0],   Track ID = 1
*********************************************************************
Step#      X         Y         Z        KineE     Volume     Process
    0     -9 cm      0 fm      0 fm     10 MeV    World   initStep
    1   -7.5 cm  -5.64 mm      0 fm     10 MeV    World   Transportation
    2   -7.5 cm  -5.64 mm      0 fm      0 eV     Lead      ionIoni

Comment 2 michel.maire 2013-01-19 18:49:50 CET

the ion is deviated in mag field, even if Q=0, and even in vacuum.
 If one desactivate ion Ionisation, trajectories looks ok.

Comment 3 kurasige 2013-01-21 01:02:41 CET

In tracking of neutral ion (i.e. Q=0 ), ion ionization gives positive charge even in Vacuum.
For example, in case of O16 atom (Q=0) with 10 MeV kinetic energy in Galactic (very low dwnsity material), ion ionization gives +5.47194 eplus charge in the end of the first step. The charge should remain 0.