Problem 2032 - Biasing mode in RadioactiveDecay
Summary: Biasing mode in RadioactiveDecay
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models (show other problems)
Version: 10.4
Hardware: All All
: P4 minor
Assignee: dennis.herbert.wright
URL:
Depends on:
Blocks:
 
Reported: 2018-02-05 18:58 CET by michel.maire
Modified: 2018-03-13 01:22 CET (History)
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Description michel.maire 2018-02-05 18:58:29 CET 
Following macro is the decay Ca47 --> Sc47 --> Ti47
In biasing mode, Sc47 are never created and only ~30% of Ti47 are present.
What happens of the remaining 70 %

 /control/verbose 2
 /run/verbose 1
 #
 /gun/particle ion
 /gun/ion 20 47
 #
 ###/grdm/decayBiasProfile Ca47.time.data.txt
 ###/grdm/BRbias 0
 #
 /analysis/setFileName Ca47
 /analysis/h1/set 8  100  0. 30. d	#time of life
 #
 /run/printProgress 10000
 /run/beamOn 100000

Here the file Ca47.time.data.txt :
 0.	  1
 864000.  0
Comment 1 dennis.herbert.wright 2018-03-13 01:22:01 CET 
The missing Ti47 nuclei were due to a bug in G4RadioactiveDecay::AddDeexcitationSpectrumForBiasMode: stable nuclei at the end of decay chains were not being added as secondaries.  This is now fixed in tag radioactive_decay-V10-04-01.

The missing Sc nuclei is not a bug.  Biased RDM decays all chains down to the stable nuclei and collects all the secondaries at the end of the tracking step.   Since the ground state of Sc47 is not stable, it does not appear.