Message: energy conservation fails in TestEm5 using Geant4-DNA physics list. Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None energy conservation fails in TestEm5 using Geant4-DNA physics list. 

Forum: DNA/Very Low Energy
Date: Feb 12, 04:31
From: Balder <Balder>

Dear Geant4 experts/users

The TestEm5 example comes with a stacking action class which is able to print the energy of all secondaries created. When I process the txt file using a simple Python code, I realize that the sum of the energy of all secondaries is higher than the input energy in the system; nevertheless, the energy deposited in the phantom is exactly the same than the input energy. Please see details of the simulation in the file attached. Besides, the TestEm5 has integrated a kill secondaries command line, when I use this feature, the sum of all the secondaries created is less than the input energy, as expected and the energy deposited in the phantom is exactly the input energy. I also have plotted a graph that compares the energies of the secondaries at creation turning on/off the kill secondaries command line (see attached), it seems that Geant4 is creating a higher number of very low energy electrons that it should so it breaks the energy conservation.

Simulation set-up: 10 MeV protons irradiating a water phantom of 2 mm thickness, i.e all protons are absorbed in the phantom. Geant4-DNA physics list is active.

The output of the Geant4 after processing shows the following ( 10 MeV protons of 10 MeV, i.e 100 MeV total energy input in the system):

no kill active:
 energy for e- (MeV)=', 120.3801
 energy for protons (MeV)=', 633.3470
 energy for Hydrogen (MeV)=', 633.9289
 energy for gamma (MeV)=', 0.0167,
total energy=', 1387.6728

kill secs On:
 energy for e- (MeV)=', 53.5953
 energy for protons (MeV)=', 0
 energy for Hydrogen (MeV)=', 32.32403
 energy for gamma (MeV)=', 0.012,
 total energy (MeV)=', 85.9313

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2019/02/12/04.24-14392-killVsNoKill.png
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2019/02/12/04.25-40551-Mydna.mac

 Add Message Add Message
to: "energy conservation fails in TestEm5 using Geant4-DNA physics list."

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews