Problem 916

Summary:	Triton (Tritium) is not considered an unstable radioisotope
Product:	Geant4	Reporter:	j.cabello
Component:	processes/decay	Assignee:	kurasige
Status:	RESOLVED INVALID
Severity:	critical	CC:	j.cabello
Priority:	P3
Version:	8.0
Hardware:	All
OS:	All

Description j.cabello 2006-12-04 13:05:12 CET

I am trying to simulate a radioactive source of Tritium (H3) against a silicon
detector. A first experiment I want to do is to measure the deposited energy
spectrum of this radioisotope in a pure cube of silicon.
I assumed that Tritium was condidered a Generic Ion so I added the Radioactive
Decay process to this but I was quite surprised when I couldn´t simulate this
radioisotope (I had done previous experiments with other radioisotopes as C14
and S35 successfully). After a week playing with the thresholds in energy and
range, the support service told me that Triton is not considered Generic Ions
and so, it´s not considered unstable, so I can´t add the Radioactive Decay
process to this radioisotope, it doesn´t decay, so it doesn´t generate the
typical beta-electrons of this source that I´m trying to detect.
I think this is a bug in Geant4 because this radioisotope is unstable and should
be considered to add the Radioactive Decay process to this radioisotope.

Comment 1 kurasige 2006-12-04 17:34:59 CET

It is not a bug. Tritium has long life time (12.33 year) and is regarded as
"stable" nuclei for most cases.

If you want to simulate decay of Tritium, add the Radioactive decay to the
Tritium as well as GenericIon. Please do not forget to set life time to Tritium
before adding the Radioactive decay. (see below)

 G4RadioactiveDecay*  theRadioactiveDecay = new G4RadioactiveDecay();
 Triton()->SetPDGLifeTime(12.33*365*24*3600*second);
 G4ProcessManager* pmanager = Triton()->GetProcessManager();
 pmanager ->AddProcess(theRadioactiveDecay);
 pmanager ->SetProcessOrdering(theRadioactiveDecay, idxPostStep);
 pmanager ->SetProcessOrdering(theRadioactiveDecay, idxAtRest);