Problem 1359 - non energy conservation in radioactiveDecay in fly
Summary: non energy conservation in radioactiveDecay in fly
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic (show other problems)
Version: 9.5
Hardware: All All
: P5 normal
Assignee: desorgher
URL:
Depends on:
Blocks:
 
Reported: 2012-09-22 12:45 CEST by michel.maire
Modified: 2013-02-07 19:02 CET (History)
1 user (show)

See Also:

Attachments
macro for example rdecay01 (105 bytes, text/plain)
2012-09-22 12:45 CEST, michel.maire 		Details
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Description michel.maire 2012-09-22 12:45:27 CEST 
Created attachment 189 [details]
macro for example rdecay01

Decay in fly do not conserve energy.
In the example below Po212 --> Pb208 + alpha
 - for Ekin = 0 eV, recoil Pb208 has correct energy 169 keV
 - for Ekin = 1 eV, recoil becomes 39 MeV

 These 2 outputs have been produced in rdecay01 with the attached macro.

*********************************************************************************************************
* G4Track Information:   Particle = Po212[0.0],   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0      0 fm      0 fm      0 fm      0 eV      0 eV      0 fm      0 fm      World   initStep
    1      0 fm      0 fm      0 fm      0 eV      0 eV      0 fm      0 fm      World   RadioactiveDecay

    :----- List of secondaries ----------------
      Pb208[0.0]:  energy = 169.3 keV  time = 183.7 ns 
           alpha:  energy = 8.785 MeV  time = 183.7 ns 
    :------------------------------------------

*********************************************************************************************************
* G4Track Information:   Particle = Po212[0.0],   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    0      0 fm      0 fm      0 fm      1 eV      0 eV      0 fm      0 fm      World   initStep
    1      0 fm      0 fm    139 um      1 eV      0 eV    139 um    139 um      World   RadioactiveDecay

    :----- List of secondaries ----------------
      Pb208[0.0]:  energy = 39.16 MeV  time = 145.8 ns 
           alpha:  energy = 12.72 MeV  time = 145.8 ns 
    :------------------------------------------
Comment 1 dennis.herbert.wright 2013-02-07 19:02:17 CET 
Problem fixed by Laurent: 
force the boost of the decay products in line 1598.
The parent energy considered in the boost is the total energy of the fully stripped parent ion rather than the total energy of dynamic ion where the
energy of shell electrons is taken into account.

Some difference in momentum and energy balance is still observed but much
less than before.

Fix included in 9.6-patch-01.