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None Getting wrong cross section using HP model 

Forum: Hadronic Processes
Date: 04 Feb, 2013
From: <KJan>

Greetings Geant4 community,

I am using the ParaFission model with HP cross sections to study neutron induced fission in U-238. The cross section for a 15 MeV neutron in the G4NDL file (Fission/CrossSection/92_238_Uranium) is 1.234624 barn. However when I count the number of fission events and calculate the cross section I get a 36% higher cross section. I have also reproduced the problem for the capture reaction so it is not only fission that is affected.

My setup is simple, I shoot 15 MeV neutrons at a 1 um thick U238 target and count the number of events where the primary particle produces fission fragments (in the nCapture case I checked for production of U239).

Below is a list of the things I have tried so far:

1) Change target width.
2) Change target to U235.
3) Edited and changed the cross sections in the G4NDL file.
4) Used 2, 5, 10, 12 and 17 MeV neutrons instead.
5) Inactivated the nInelastic process.

There seems to be a very slight energy dependence but it is very small with no apparent pattern. All other test have ended up with a 36% larger cross section than is found in the G4NDL file.

I have also checked the mean value of the physical interaction length calculated by the process. It has the correct value of 1/([atomic density][G4NDL cross section]).

I use Geant4.9.6 and G4NDL4.2.

I am happy to receive any suggestions of what I could do to track down what is wrong with my simulations.


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1 None: Re: Getting wrong cross section using HP model   (michel maire - 04 Feb, 2013)
(_ Ok: Re: Getting wrong cross section using HP model   (KJan - 05 Feb, 2013)
(_ None: Re: Getting wrong cross section using HP model   (michel maire - 05 Feb, 2013)
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