Problem 1058 - unexpected gamma ray lines ---G4.9.2
Summary: unexpected gamma ray lines ---G4.9.2
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models/neutron_hp (show other problems)
Version: 9.2
Hardware: All All
: P3 major
Assignee: tkoi
URL:
Depends on:
Blocks:
 
Reported: 2009-04-04 01:57 CEST by Chao Zhang
Modified: 2011-10-24 21:15 CEST (History)
0 users

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Attachments
an example of unexpected gamma ray lines (169.71 KB, application/pdf)
2009-04-04 01:57 CEST, Chao Zhang 		Details
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Description Chao Zhang 2009-04-04 01:57:56 CEST 
Created attachment 45 [details]
an example of unexpected gamma ray lines

I am using a simple geometry which is mainly constituted by natural Germanium and Lead. And 2MeV neutron generated and passed through those materials. I found lots of unexpected gamma ray lines produced in the two materials. The attached file is one of example.
Comment 1 tkoi 2010-09-13 17:07:10 CEST 
These ultra low energy photons are emitted for better energy and momentum balances. 
You can user G4NEUTRONHP_DO_NOT_ADJUST_FINAL_STATE flag for stopping emission of these photons, but the balances will be much worse.

Now we are discussing anther methods or applying thresholds for such photons.

Tatsumi
Comment 2 tkoi 2010-09-24 03:17:44 CEST 
We make a decision that we will not produce photons for the purpose below the lower limit (1keV) of Geant4 standard EM. 
This slightly affects conservation level, but we believe it is negligible.
We will implement this coming release which planed on 2010 Dec.
If anyone wants to make comment about this decision, please let us know. 

Tatsumi
Comment 3 tkoi 2011-10-24 21:15:57 CEST 
I am sorry 
I forget to close this.
It already passed more than a year.
So please make a new report who want to have some comments about this.

Thank you very much.

Tatsumi