While tracking (muons) with spin in the presence of parallel worlds spin information in post steps is not defined: -=-=-=-=-= With Parallel Words -=-=-=-=-= ********************************************************************************************************* * G4Track Information: Particle = mu+, Track ID = 1, Parent ID = 0 ********************************************************************************************************* Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName 0 0 7.06e+03 0 2.99e+03 0 0 0 RingVacuum initStep ... >>AlongStepDoIt (process by process): Process Name = CoupledTransportation ++G4Step Information Address of G4Track : 0x7ff6ea349e20 Step Length (mm) : 5.000000000000001e-07 Energy Deposit (MeV) : 0 ----------------------------------------------------------------------- StepPoint Information PreStep PostStep ----------------------------------------------------------------------- Position - x (mm) : 05.000000000000001e-07 Position - y (mm) : 7065 7065 Position - z (mm) : 0 0 Global Time (ns) : 01.667820475990761e-09 Local Time (ns) : 01.667820475990761e-09 Proper Time (ns) : 05.691552929717019e-11 Momentum Direct - x : 1 0.9999999999999999 Momentum Direct - y : 0 0 Momentum Direct - z : 0 0 Momentum - x (MeV/c): 3094.349662748337 3094.349662748336 Momentum - y (MeV/c): 0 0 Momentum - z (MeV/c): 0 0 Total Energy (MeV) : 3096.153020421933 3096.153020421932 Kinetic Energy (MeV): 2990.494653421933 2990.494653421932 Velocity (mm/ns) : 299.6177205138951 299.6177205138951 Volume Name : RingVacuum RingVacuum Safety (mm) : 0 0 Polarization - x : -1 nan <------- Polarization - y : 0 nan Polarization - Z : 0 nan Weight : 1 1 Step Status : Undefined AlongStep Proc. Process defined Step: Undefined TrackingPlaneWorld ----------------------------------------------------------------------- !Note! Safety of PostStep is only valid after all DoIt invocations. ++G4ParticleChange Information ----------------------------------------------- G4ParticleChange Information ----------------------------------------------- # of 2ndaries : 0 ----------------------------------------------- Energy Deposit (MeV): 0 Non-ionizing Energy Deposit (MeV): 0 Track Status : Alive True Path Length (mm) : 5e-07 Stepping Control : 0 Mass (GeV) : 0 Charge (eplus) : 0 MagneticMoment : 0 : = 0*[e hbar]/[2 m] Position - x (mm) : 5e-07 Position - y (mm) : 7.06e+03 Position - z (mm) : 0 Time (ns) : 1.67e-09 Proper Time (ns) : 5.69e-11 Momentum Direct - x : 1 Momentum Direct - y : 0 Momentum Direct - z : 0 Kinetic Energy (MeV): 2.99e+03 Velocity (/c): 0.999 Polarization - x : nan <------- Polarization - y : nan Polarization - z : nan Touchable (pointer) : 0 ++List of secondaries generated (x,y,z,kE,t,PID): No. of secodaries = 0 ... >>AlongStepDoIt (after all invocations): ++List of invoked processes 1) CoupledTransportation 2) msc 3) TrackingPlaneWorld 4) StorageRegionWorld 5) muIoni ++G4Step Information Address of G4Track : 0x7ff6ea349e20 Step Length (mm) : 5.000000000000001e-07 Energy Deposit (MeV) : 1.551700173395916e-32 ----------------------------------------------------------------------- StepPoint Information PreStep PostStep ----------------------------------------------------------------------- Position - x (mm) : 05.000000000000001e-07 Position - y (mm) : 7065 7065 Position - z (mm) : 0 0 Global Time (ns) : 01.667820475990761e-09 Local Time (ns) : 01.667820475990761e-09 Proper Time (ns) : 05.691552929717019e-11 Momentum Direct - x : 1 0.9999999999999999 Momentum Direct - y : 0 0 Momentum Direct - z : 0 0 Momentum - x (MeV/c): 3094.349662748337 3094.349662748336 Momentum - y (MeV/c): 0 0 Momentum - z (MeV/c): 0 0 Total Energy (MeV) : 3096.153020421933 3096.153020421932 Kinetic Energy (MeV): 2990.494653421933 2990.494653421932 Velocity (mm/ns) : 299.6177205138951 299.6177205138951 Volume Name : RingVacuum RingVacuum Safety (mm) : 0 5e-10 Polarization - x : -1 nan <------- Polarization - y : 0 nan Polarization - Z : 0 nan Weight : 1 1 Step Status : Undefined AlongStep Proc. Process defined Step: Undefined TrackingPlaneWorld ----------------------------------------------------------------------- ++List of secondaries generated (x,y,z,kE,t,PID): No. of secodaries = 0
Created attachment 303 [details] Tarball of patches Thank you to the author Nathan Froeming for the clear demonstration of this problem. I have been able to isolate its causes and create a set of patches which address the causes. Please find attached a tar ball with patch files for these issues, and a short explanation how to apply them.
K. Genser has confirmed that the patch fixes the issue in the example. Marking as resolved. ( Will reopen if problem persists in full program or elsewhere.)
