Problem 1249

Summary:	radioactive decay, gamma de-excitation and meta-stable states
Product:	Geant4	Reporter:	dennis.herbert.wright
Component:	processes/hadronic/models/radioactive_decay	Assignee:	dennis.herbert.wright
Status:	RESOLVED FIXED
Severity:	normal	CC:	Alberto.Ribon
Priority:	P5
Version:	9.4
Hardware:	All
OS:	All

Description dennis.herbert.wright 2011-09-13 20:15:43 CEST

Bug reports transferred from closed bug report 1001 (originated by Andreas Zoglauer):

1. If there is an internal conversion (electron is ejected instead of gamma-ray),
then the energy conservation is sometimes broken:
If there is a discrete gamma transition, then the function "void
G4DiscreteGammaTransition::SelectGamma()", selects the transition and, if an
internal conversion electron is emitted, it randomly selects a shell and
SUBTRACTS the binding energy from the ejected electron. The shell number is
stored and later retrieved by G4DecayProducts *G4NuclearDecayChannel::DecayIt
(G4double theParentMass) to produce the Auger-Electrons.
The problem now is, that during G4FragmentVector*
G4VGammaDeexcitation::DoChain() MULTIPLE conversions can happen, however, only
the LAST shell index is stored, and in the DecayIt function and only the LAST
emptied shell is filled, resulting in missing energy!


2. Geant4 correctly recognizes that the 73-Ga decay ends in a metastable isotope
at 66.7 keV. However, the second meta-stable state at 13.3 keV is not reached,
although the data tables contain the information along with the correct half
life.

Comment 1 Alberto.Ribon 2014-07-02 20:18:09 CEST

Dennis (to whom the bug is assigned) said that this bug contains the still unfixed items that remain from the original long list in bug report 1001. The main problem of 1249 is the energy non-conservation in internal conversion mode. This is only one of many non-conservations identified in radioactive decay.
Fixing them is part of an ongoing project which is not trivial and
requires re-design work. This will likely take the rest of this year.

Comment 2 dennis.herbert.wright 2014-12-16 02:45:49 CET

Part 2 of this problem report has been fixed.  Both the 66.7 and the 13.3 keV lines now appear as they should.

Progress has been made on part 1, but some developments in photon evaporation are still required.

Comment 3 dennis.herbert.wright 2015-11-12 21:03:01 CET

The re-designed radioactive decay model now decays each nuclide in a separate step, so there is no longer a chain decay in one step. As a result part 1 of this bug report is now also fixed.