Problem 1749 - No atomic deexcitation after Nuclear deexcitation via internal conversion
Summary: No atomic deexcitation after Nuclear deexcitation via internal conversion
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models/de_excitation/evaporation (show other problems)
Version: 10.1
Hardware: All All
: P5 critical
Assignee: dennis.herbert.wright
URL:
Depends on:
Blocks:
 
Reported: 2015-05-29 08:20 CEST by Andreas
Modified: 2015-11-18 22:35 CET (History)
2 users (show)

See Also:


Attachments
One slide image. Author: E.Shields (246.85 KB, image/tiff)
2015-11-18 16:39 CET, maddalena.antonello
Details

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Description Andreas 2015-05-29 08:20:32 CEST
Hello,

Looking at the decay of the meta-stable state Ag109[88.034] I would expect the total deposited energy in my detector to be 88.034 keV. While I get a small full-energy peak at 88.034 keV (corresponding to the 3.7% of X-rays which should be emitted), I do get peaks at 62.5 keV and 84.5 keV corresponding to 88 keV minus 25.5 (K-edge) or minus L-edges, etc.

Looking into the source code of G4PhotonEvaporation, G4NulcearDecayChannel and G4DiscreteGammaDeexcitation and G4VGammaDeexitation, in these cases internal conversion happens (excitation energy is transfered to electron). The code handles correctly the binding energy and thus transfers less energy to the electron and generated a vacancy in the shell -- that's all as expected. However, the information about the generated shell vacancy in G4VGammaDeexcitation::GenerateGamma is not passed on to the classes upstream, thus G4NulcearDecayChannel::DecayIt cannot perform the atomic deexcitation, since it simply doesn't know it happened. As consequence, we do not have energy conservation since we are missing some fluoresence X-rays/Auger electrons.

The problem can be easily reproduced using Ag109[88.034] with the rdecay01 example.

This problem has been found with Geant4 10.01.p01 and also in 10.00.p04 the spectrum does not show the correct peaks.

If you have further questions, feel free to contact me.

Cheers,
Andreas
Comment 1 dennis.herbert.wright 2015-06-11 01:54:18 CEST
I reproduce the problem.  I'm getting energy non-conservation of 25.5 keV.   I'll start looking at the gamma deexcitation code.
Comment 2 maddalena.antonello 2015-11-18 16:39:20 CET
Created attachment 367 [details]
One slide image. Author: E.Shields
Comment 3 maddalena.antonello 2015-11-18 16:41:53 CET
The same problem was found with 40K EC decay. See attached slides. Is there a patch we can use?

Thanks!
Comment 4 dennis.herbert.wright 2015-11-18 22:35:56 CET
I believe this now fixed using Andreas' method as posted in bug report 1756.
The fix should appear in release 10.2 within two or three weeks.