Dear all,
after updating my installation of Geant4 from 10.6 to 10.7, I frequently get aborted events without having changed my code or the configuration:
-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : TRACK003
issued by : G4ParticleChange::CheckIt()
momentum, energy, and/or time was illegal
*** Event Must Be Aborted ***
G4WT66 > G4Track (0x7f0ef3441fb0) - track ID = 38, parent ID = 1
G4WT66 > Particle type : pi- - creator process : pi+Inelastic, creator model : Undefined
G4WT66 > Kinetic energy : 2.77688 GeV - Momentum direction : (0.125509,-0.103605,0.986668)
G4WT66 > Step length : -765.914 km - total energy deposit : 0 eV
G4WT66 > Pre-step point : (1.4252,-0.256613,189.064) - Physical volume : World (G4_AIR)
G4WT66 > - defined by : Transportation - step status : 1
G4WT66 > Post-step point : (-9.61289e+07,7.93527e+07,-7.55703e+08) - Physical volume : World (G4_AIR)
G4WT66 > - defined by : hIoni - step status : 3
G4WT66 > *** Note: Step information might not be properly updated.
G4WT66 >
-------- EEEE -------- G4Exception-END --------- EEEE -------
Is this something I should worry about? What is the reason for the odd step length?
Best regards,
Simon
I enables /tracking/verbose 6 in order to get some more information, I have the full trace for one of the events attached:
The (probably) relevant part is here:
#Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName
2 18.1 6.48 307 2.17e+03 0.0988 0.4 1.44 World Transportation
>>DefinePhysicalStepLength (List of proposed StepLengths):
++ProposedStep(PostStep ) = 66132569079096.55 : ProcName = UserSpecialCut (No ForceCondition)
++ProposedStep(PostStep ) = 1.797693134862316e+308 : ProcName = StepLimiter (No ForceCondition)
++ProposedStep(PostStep ) = 798571.2073791905 : ProcName = pi+Inelastic (No ForceCondition)
++ProposedStep(PostStep ) = 921533.6251910743 : ProcName = hadElastic (No ForceCondition)
++ProposedStep(PostStep ) = 91621.19083936959 : ProcName = Decay (No ForceCondition)
++ProposedStep(PostStep ) = 29931874.27808011 : ProcName = CoulombScat (No ForceCondition)
++ProposedStep(PostStep ) = 177116427.9302929 : ProcName = hPairProd (No ForceCondition)
++ProposedStep(PostStep ) = 1065286434.804242 : ProcName = hBrems (No ForceCondition)
++ProposedStep(PostStep ) = 57.46375384060007 : ProcName = hIoni (No ForceCondition)
++ProposedStep(PostStep ) = 1.797693134862316e+308 : ProcName = Transportation (Forced)
++ProposedStep(AlongStep) = -213761960.567948 : ProcName = hIoni (CandidateForSelection)
++ProposedStep(AlongStep) = -213761960.567948 : ProcName = msc (NotCandidateForSelection)
++ProposedStep(AlongStep) = -213761960.567948 : ProcName = Transportation (CandidateForSelection)
G4ParticleChange::CheckIt : the local time goes back !! Difference: 714343.8390946602[ns]
pi+ E=2165.480407932291 pos=0.01811530321190624, 0.006477231000467316, 0.3069085078022522 global time=1.692841721526027 local time=0.004803312919536029 proper time=0.0002908016133874408
G4ParticleChange::CheckIt : the proper time goes back !! Difference: 43253.29996619633[ns]
pi+ E=2165.480407932291 pos=0.01811530321190624, 0.006477231000467316, 0.3069085078022522 global time=1.692841721526027 local time=0.004803312919536029 proper time=0.0002908016133874408
-----------------------------------------------
G4ParticleChange Information
-----------------------------------------------
# of 2ndaries : 0
-----------------------------------------------
Energy Deposit (MeV): 0
Non-ionizing Energy Deposit (MeV): 0
Track Status : Alive
True Path Length (mm) : -2.14e+08
Stepping Control : 0
First Step In the voulme :
Mass (GeV) : 0
Charge (eplus) : 0
MagneticMoment : 0
: = 0*[e hbar]/[2 m]
Position - x (mm) : -1.99e+07
Position - y (mm) : -2.67e+06
Position - z (mm) : -2.13e+08
Time (ns) : -7.14e+05
Proper Time (ns) : -4.33e+04
Momentum Direct - x : 0.0933
Momentum Direct - y : 0.0125
Momentum Direct - z : 0.996
Kinetic Energy (MeV): 2.17e+03
Velocity (/c): 0.998
Polarization - x : 0
Polarization - y : 0
Polarization - z : 0
Touchable (pointer) : 0x55ff83406740
-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : TRACK003
issued by : G4ParticleChange::CheckIt()
momentum, energy, and/or time was illegal
*** Event Must Be Aborted ***
G4Track (0x55ff86ea6848) - track ID = 80, parent ID = 70
Particle type : pi+ - creator process : Decay, creator model : Undefined
Kinetic energy : 2.16548 GeV - Momentum direction : (0.0932966,0.012506,0.99556)
Step length : -213.762 km - total energy deposit : 0 eV
Pre-step point : (18.1153,6.47723,306.909) - Physical volume : World (G4_AIR)
- defined by : Transportation - step status : 1
Post-step point : (-1.99433e+07,-2.67331e+06,-2.12813e+08) - Physical volume : World (G4_AIR)
- defined by : hIoni - step status : 3
*** Note: Step information might not be properly updated.
-------- EEEE -------- G4Exception-END --------- EEEE -------
Can someone make sense of this?
/Simon
Roden
3
Hi Simon,
I find the same issue in my simulations with Geant4.10.7 (and patch 1), where this did not exist in 4.10.4. It seems to only affect pions and I found that almost all aborted events occurred at/crossed material boundaries/volumes, calculating a negative step size of km in magnitude. There was some small percentage that were not aborted at the boundary but they were aborted in the following step. I did not identify an individual process that caused this though.
From your full trace I think the same thing is happening, it occurs right after going between
support_telescope5_phys_0 and World volumes and has the same symptoms, could you confirm?
I do not have a solution, but perhaps this confirmation may help towards diagnosing the problem.
Regards,
Roden
Hi Roden,
I see pions (pos/neg) as well as kaons and protons causing this issue, so it seems to definitely be a hadronic issue. I can confirm your other observation that this always seems to happen at volume boundaries.
Best regards,
Simon
Roden
5
Hi Simon,
Interesting that it occurs with protons for you, I only see this with pions (charged and uncharged) that have been produced from an initial proton beam, but no protons are aborted from what I can see.
Regards,
Roden
Hi Roden,
here is an example for a proton from my simulation:
-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : TRACK003
issued by : G4ParticleChange::CheckIt()
momentum, energy, and/or time was illegal
*** Event Must Be Aborted ***
G4WT2 > G4Track (0x7f69088118b8) - track ID = 34, parent ID = 1
G4WT2 > Particle type : proton - creator process : pi+Inelastic, creator model : Undefined
G4WT2 > Kinetic energy : 24.0358 GeV - Momentum direction : (0.0175435,0.0104732,0.999791)
G4WT2 > Step length : -36116.9 km - total energy deposit : 0 eV
G4WT2 > Pre-step point : (-0.0743188,-1.3641,301.988) - Physical volume : World (G4_AIR)
G4WT2 > - defined by : Transportation - step status : 1
G4WT2 > Post-step point : (-6.33617e+08,-3.7826e+08,-3.61093e+10) - Physical volume : World (G4_AIR)
G4WT2 > - defined by : hIoni - step status : 3
G4WT2 > *** Note: Step information might not be properly updated.
G4WT2 >
-------- EEEE -------- G4Exception-END --------- EEEE -------
I am using a 120 GeV Pi+ beam as primary particles, so this proton definitely is a secondary from an interaction.
I also see more arcane excitation states:
-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : TRACK003
issued by : G4ParticleChange::CheckIt()
momentum, energy, and/or time was illegal
*** Event Must Be Aborted ***
G4WT2 > G4Track (0x7f6908690978) - track ID = 11, parent ID = 1
G4WT2 > Particle type : anti_sigma+ - creator process : pi+Inelastic, creator model : Undefined
G4WT2 > Kinetic energy : 24.6322 GeV - Momentum direction : (-0.0122384,-0.0109746,0.999865)
G4WT2 > Step length : -11440.2 km - total energy deposit : 0 eV
G4WT2 > Pre-step point : (-0.780206,0.184211,204.556) - Physical volume : World (G4_AIR)
G4WT2 > - defined by : Transportation - step status : 1
G4WT2 > Post-step point : (1.4001e+08,1.25552e+08,-1.14387e+10) - Physical volume : World (G4_AIR)
G4WT2 > - defined by : hIoni - step status : 3
G4WT2 > *** Note: Step information might not be properly updated.
G4WT2 >
-------- EEEE -------- G4Exception-END --------- EEEE -------
/Simon
I played a bit around with different physics lists:
-
FTFP_BER_EMV - no aborted events
-
FTFP_BER_EMX - no aborted events
-
FTFP_BER_EMY - problem with aborted events
-
FTFP_BER_EMZ - problem with aborted events
-
FTFP_BER_LIV - no aborted events
-
QGSP_BER_EMV - no aborted events
-
QGSP_BER_EMX - no aborted events
-
QGSP_BER_EMY - problem with aborted events
-
QGSP_BER_EMZ - problem with aborted events
-
QGSP_BER_LIV - no aborted events
In conclusion, it seems to only appear with the electromagnetic extensions _EMY and _EMZ. Interestingly, _LIV does not show the problem despite being an extention of _EMY afaik.
/Simon
Hello,
thank you for pointing to a possible problem. Unfortunately, not obvious where and why this happens. Can you, please, formulate it in the Bugzilla bug report system (https://bugzilla-geant4.kek.jp/)?
VI
Hi,
any news on that: I could not see any update from the Bugzilla report. I have a very similar problem, when simulating some ions in 10.7.
E.g. Pb208:
G4ParticleChange::CheckIt : the proper time goes back !! Difference: 0.0002[ns]
Pb208 E=0.17 pos=-0.00085, -0.0054, 0.0022 global time=2.3e+13 local time=0 proper time=0
-----------------------------------------------
G4ParticleChange Information
-----------------------------------------------
# of 2ndaries : 0
-----------------------------------------------
Energy Deposit (MeV): 0
Non-ionizing Energy Deposit (MeV): 0
Track Status : Alive
True Path Length (mm) : -7.96e-05
Stepping Control : 0
First Step In the voulme :
Mass (GeV) : 0
Charge (eplus) : 0
MagneticMoment : 0
: = 0*[e hbar]/[2 m]
Position - x (mm) : -0.851
Position - y (mm) : -5.44
Position - z (mm) : 2.25
Time (ns) : -0.000201
Proper Time (ns) : -0.000201
Momentum Direct - x : 0.68
Momentum Direct - y : 0.73
Momentum Direct - z : 0.0609
Kinetic Energy (MeV): 0.169
Velocity (/c): 0.00132
Polarization - x : 0
Polarization - y : 0
Polarization - z : 0
Touchable (pointer) : 0x381caa0
G4VParticleChange::CheckIt : the true step length is negative !! Difference: 8e-05[MeV]
Pb208 E=0.17 pos=-0.00085, -0.0054, 0.0022
-----------------------------------------------
would not be the case in 10.6?
