Problem 1092

Summary: decay of Na-22 with Radioactive Decay Module is incorrect
Product: Examples/Extended Reporter: Victor Golovko <vgolovko>
Component: radioactivedecay/exrdmAssignee: flei
Status: RESOLVED INVALID    
Severity: trivial CC: pandola
Priority: P5    
Version: 9.2   
Hardware: PC   
OS: Linux   
Attachments: proposed file for radioactive decay of Na-22

Description Victor Golovko 2009-11-17 21:27:47 CET 
Dear Geant4 developers,

I was trying to use 'exrdm' example in order to get initial spectra for all the particles in the decay of Na-22. I have found that Radioactive Decay Module generates gamma's with the energy of 1567.7 keV. However, according to the NNDC internet data-base for Na-22, there is no gamma's with this energy. Looking at the library that has been supplied with Geant4 (version 4.9.2 with path p02) I have found that if I will modify the exiting file for the Radioactive Decay Library v3.2 to the one that I have included into this message I can remove the 1567.7 keV gamma line.

I would be appreciated if someone more knowledgeable about the radioactive decay library would check data-file for Na-22 in the RadioactiveDecay3.2.

Thank you in advance,
Victor.
17 November, 2009

----------------------
Dr. Victor V. GOLOVKO
Queen’s University
Department of Physics, Stirling Hall
Kingston, Ontario, 
Canada K7L3N6
Phone: +1 613-533-2694 
Fax:   +1 613-533-6463
E-mail: vgolovko@owl.phy.queensu.ca
Comment 1 Victor Golovko 2009-11-17 21:29:34 CET 
Created attachment 61 [details]
proposed file for radioactive decay of Na-22
Comment 2 Luciano Pandola 2010-02-18 09:55:19 CET 
Dear Victor,

I tried it and I could not reproduce the problem.

Actually, the Q-value of the Na-22 decay is 2842.2 keV, so when the final state has excitation energy 1274.57 keV, the available energy for the beta+ decay should be  2842.2-1274.57 = 1567.63 keV, as reported in the original database file.

I run a few 10000 events and I could find any 1567-keV gamma-ray emitted in the decay of Na-22. 

For example, for one single event I have 
e+: 269 keV 
   --> 2 annihilation gammas 511 keV
nu_e: 277 keV 
gamma: 1275 keV
Ne22: 13 eV
total: 2842 keV.

You have with some probability (about 9%) mono-energetic 1.567-keV neutrinos, following electron capture, and no positrons.

Ciao,
Luciano
Comment 3 flei 2010-05-05 19:32:42 CEST 
Dear Victor,

Checked with version 9.3 and have found no 1567.7 keV gamma at all with 100000 Na-22 decays. This confirms the finding of Luciano. 

Regards

Fan