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Question Cross Section for the 3He(n,p)3H reaction 

Keywords: 3He(n,p)3H, Tracking, Energy, Hadronic Physics, Neutron Inelastic
Forum: Hadronic Processes
Date: 04 Dec, 2007
From: Sascha Falahat <Sascha Falahat>

Hello everybody,

I have a question regarding the cross section that GEANT4 uses for the 3He(n,p)3H reaction.

The physics lists I used are QGSP_BERT_HP, QGSP_BIC_HP or LHEP_PRECO_HP. The Data Libraries i use are G4NDL3.11.

I tried to convince myself that the cross section used for that reaction is correct by looking at the energy of the neutron at the interaction point, the initial neutron energy being in the 0 to 20 MeV range.

I observe that all the (n,p) reactions occur when the kinemtic energy of the neutron is 0. I can observe that by either looking at the verbose output of the tracking or by summing the kinetic energy of the proton and the triton in preUserTrackingAction.

For example the out put by the verbose output looks like :

**********************************

   25      124     64.2       50  5.63e-07        0     6.95       387     HePlane Transportation
   26      124       65     51.7         0        0     1.93       389     HePlane NeutronInelastic

*********************************************************************************************************
* G4Track Information:   Particle = triton,   Track ID = 24,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      124       65     51.7     0.191        0        0         0     HePlane initStep
    1      124     63.8     52.6         0    0.191     1.47      1.47     HePlane hIoni

*********************************************************************************************************
* G4Track Information:   Particle = proton,   Track ID = 23,   Parent ID = 1
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
    0      124       65     51.7     0.573        0        0         0     HePlane initStep

***********************************

I realize that the maximum of the (n,p) cross section is at very low energy, however I am expecting a few count to occur at higher energy. Why don't I observe any counts with higher neutron energy?

I also compared the cross sections coming from the ENDF website and the cross section file of G4NDL3.11 and see quite a difference above 4 MeV. Is there a reason for this?

Thanks,

Sascha Falahat

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1 None: Re: Cross Section for the 3He(n,p)3H reaction   (Koi, Tatsumi - 04 Dec, 2007)
(_ None: Re: Cross Section for the 3He(n,p)3H reaction   (Sascha Falahat - 11 Dec, 2007)
(_ None: Re: Cross Section for the 3He(n,p)3H reaction   (Koi, Tatsumi - 11 Dec, 2007)
(_ None: Re: Cross Section for the 3He(n,p)3H reaction   (Sascha Falahat - 12 Dec, 2007)
(_ None: Re: Cross Section for the 3He(n,p)3H reaction   (Koi, Tatsumi - 13 Dec, 2007)
(_ None: Re: Cross Section for the 3He(n,p)3H reaction   (Sascha Falahat - 17 Dec, 2007)
(_ Question: Re: Cross Section for the 3He(n,p)3H reaction   (HuangHong - 27 Oct, 2015)
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