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Question Gammas from neutron capture on Cd113 

Forum: Hadronic Processes
Date: 27 Jul, 2016
From: Camille B.-Champagne <Camille B.-Champagne>

Dear experts,

I have observed gamma lines I do not understand when looking at the neutron capture process of thermal neutrons on cadmium 113.

According to the NNDC intensities: http://www.nndc.bnl.gov/capgam/byn/page128.html there should be only two main peaks at 558 and 651 keV.

When I run the Hadr03 example with the following macro file:

 # Macro file for "Hadr03.cc"
 #
 /control/verbose 2
 /run/verbose 2
 #
 /testhadr/det/setIsotopeMat Cd113 48 113 8.69 g/cm3
 #
 /run/initialize
 #
 /gun/particle neutron
 /gun/energy 0.05 eV
 #
 /process/list
 /process/inactivate hadElastic
 /process/inactivate neutronInelastic
 /process/inactivate nFission
 #
 /analysis/setFileName Cd113Test
 /analysis/h1/set 2  500  0 12 MeV       #gamma
 #
 /run/printProgress 10000
 #
 /run/beamOn 1000000

I see three large peaks at ~580 keV (close but not quite where expected) and 4 and 4.4 MeV (see attached figure). I do not understand where these other peaks come from.

I have seen 2 previous thread on this topic in the forum:

http://hypernews.slac.stanford.edu/HyperNews/geant4/get/hadronprocess/1165.html

And from last year: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/hadronprocess/1479.html

In that last one, the same behaviour that I see is also observed but no clear resolution was reached.

Based on the suggestions in both of those older threads, I have run again setting:

G4NEUTRONHP_DO_NOT_ADJUST_FINAL_STATE=1

and/or

G4NEUTRONHP_USE_ONLY_PHOTOEVAPORATION=1

I see no change in the result when changing either environment variable.

So where do the 4 and 4.4 MeV gammas come from? I am using version 4.10.1p1

Your guidance is much appreciated,

Camille

I

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2016/07/27/05.28-85823-cadmium113.gif

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1 None: Re: Gammas from neutron capture on Cd113   (Camille B.-Champagne - 03 Aug, 2016)
(_ None: Re: Gammas from neutron capture on Cd113   (Koi, Tatsumi - 03 Aug, 2016)
(_ None: Re: Gammas from neutron capture on Cd113   (Camille B.-Champagne - 05 Aug, 2016)
(_ None: Re: Gammas from neutron capture on Cd113   (Koi, Tatsumi - 08 Aug, 2016)
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