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None Elastic neutron scattering in QGSP_BERT_HP 

Forum: Physics List
Date: 05 Nov, 2012
From: Adam Anderson <Adam Anderson>

I am simulating a 3He neutron detector that is surrounded by polyethylene. The goal is for the polyethylene to moderate fast neutrons to thermal energies, when they subsequently capture on 3He in the detector producing a proton and triton. It is therefore important that the physics models that I use can reliably simulate neutrons from a few MeV to thermal energies. The first question is: are there any reference physics lists that are recommended for this purpose? If I write my own physics list for the neutrons, what models are recommended?

Secondly, I tried using the QGSP_BERT_HP physics list, but I noticed that the neutrons were not interacting in the polyethylene as expected. The dominant interaction for neutrons in polyethylene should be elastic scattering on hydrogen, but this process did not appear to be occurring (see hadronic process summary for neutrons below). I was able to write my own version of QGSP_BERT_HP with elastic scattering on, but is elastic neutron scattering really turned off in QGSP_BERT_HP? Is it possible that this behavior is indicative of another problem with my geant4 installation? I am using version 9.5.p01. Thanks!

                                 Hadronic Processes for <neutron>
                                 -----------------------------------
   NeutronInelastic  Models:                         FTFP: Emin(GeV)=    4  Emax(GeV)= 100000
                                           BertiniCascade: Emin(GeV)= 0.0199  Emax(GeV)= 5
                                       NeutronHPInelastic: Emin(GeV)=    0  Emax(GeV)= 0.02

   NeutronInelastic  Crs sctns:                          : Emin(GeV)=    0  Emax(GeV)= 100000
                                      Barashenkov-Glauber: Emin(GeV)=    0  Emax(GeV)= 100000
                                     NeutronHPInelasticXS: Emin(GeV)=    0  Emax(GeV)= 0.02
                                     G4CrossSectionPairGG: Emin(GeV)=    0  Emax(GeV)= 100000
                        G4CrossSectionPairGG: Wellisch-Laidlaw cross sections 
                          below 91 GeV, Glauber-Gribov above 
                                         GheishaInelastic: Emin(GeV)=    0  Emax(GeV)= 100000

           nCapture  Models:                   G4LCapture: Emin(GeV)= 0.0199  Emax(GeV)= 20000
                                         NeutronHPCapture: Emin(GeV)=    0  Emax(GeV)= 0.02

           nCapture  Crs sctns:        NeutronHPCaptureXS: Emin(GeV)=    0  Emax(GeV)= 0.02
                                         GheishaCaptureXS: Emin(GeV)=    0  Emax(GeV)= 100000

           nFission  Models:                   G4LFission: Emin(GeV)= 0.0199  Emax(GeV)= 20000
                                         NeutronHPFission: Emin(GeV)=    0  Emax(GeV)= 0.02

           nFission  Crs sctns:        NeutronHPFissionXS: Emin(GeV)=    0  Emax(GeV)= 0.02
                                         GheishaFissionXS: Emin(GeV)=    0  Emax(GeV)= 100000

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1 Idea: Re: Elastic neutron scattering in QGSP_BERT_HP   (Vladimir Ivanchenko - 16 Nov, 2012)
(_ Idea: Re: Elastic neutron scattering in QGSP_BERT_HP   (Vladimir Ivanchenko - 16 Nov, 2012)
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