Problem 2057 - Meaningless dataset for neutron capture process in *_HP physics lists
Summary: Meaningless dataset for neutron capture process in *_HP physics lists
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: physics_lists (show other problems)
Version: 10.4
Hardware: All All
: P4 enhancement
Assignee: Vladimir.Ivantchenko
URL:
Depends on:
Blocks:
 
Reported: 2018-05-03 12:46 CEST by Artem Zontikov
Modified: 2018-08-14 10:37 CEST (History)
2 users (show)

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Description Artem Zontikov 2018-05-03 12:46:55 CEST 
Hello.

Each *_HP physics list (and Shielding) has G4NeutronCaptureXS dataset for neutron capture process. It returns cross-sections for neutrons below 20 MeV and therefore it is not used at all since it is shadowed by NeutronHPCaptureXS.

  Process: nCapture
        Model:          NeutronHPCapture: 0 eV  ---> 20 MeV
        Model:               nRadCapture: 19.9 MeV ---> 100 TeV
     Cr_sctns:        NeutronHPCaptureXS: 0 eV  ---> 20 MeV
     Cr_sctns:        G4NeutronCaptureXS: 0 eV  ---> 100 TeV
     Cr_sctns:        NeutronHPCaptureXS: 0 eV  ---> 20 MeV
     Cr_sctns:          GheishaCaptureXS: 0 eV  ---> 100 TeV

I think it is better this way:

  Process: nCapture
        Model:          NeutronHPCapture: 0 eV  ---> 20 MeV
        Model:               nRadCapture: 19.9 MeV ---> 100 TeV
     Cr_sctns:        NeutronHPCaptureXS: 0 eV  ---> 20 MeV
     Cr_sctns:          GheishaCaptureXS: 0 eV  ---> 100 TeV
Comment 1 Artem Zontikov 2018-06-08 15:01:55 CEST 
Also G4NeutronCaptureXS returns zero cross-section for neutrons with kinetic energy above 20 MeV and therefore shadows GheishaCaptureXS which is tabulated up to 32.7 MeV.
Comment 2 Vladimir.Ivantchenko 2018-08-14 10:37:09 CEST 
Hello,

thank you very much for this bug report. The problem is fixed in the development version of Geant4 and will be available with the next public release 10.5, December, 2018. Cannot guarantee if the fix will be backported to the next patch to 10.4.

VI