|Message: Re: Missing Implementation of Deuteron Elastic Cross Sections||Not Logged In (login)|
Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.
Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.
Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.
|1||0||1||no text / full text of posting|
|2||1||All||text for level 1 only / text for All postings|
Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.
|1||2||1||2 levels / 1 level (original posting)|
|2||3||2||3 levels / 2 levels|
|3||3||All||3 levels / all levels (all postings)|
you are right: in nearly all physics lists of Geant4, the elastic cross sections for deuteron-, triton- and alpha-nuclear reactions is zero, whereas it is not zero (so, more physical) for anti_deuteron-, anti_triton- and anti_alpha-nuclear reactions. This is not an intentional feature, but a mistake from our (Geant4) side. This mistake will be fixed in the new release of Geant4, as well as in the coming first patch of G4 10.5.
A few more details below. The old and rough cross sections from Gheisha, available in Geant4, have been used from the very beginning of Geant4. These cross sections exist for deuteron, triton and alpha, but not for the their anti-particles: for this reason, we have been using Gheisha for deuteron, triton and alpha, whereas for their anti-particles we did not have anything for several years, and then, starting with Geant4 9.5 (if I remember correctly), some Glauber-Gribov cross sections have been introduced in Geant4. Since a while, we have also Glauber-Gribov cross elastic sections for deuteron, triton and alpha, but these were used only in the special constructor G4HadronHElasticPhysics (the default being instead G4HadronElasticPhysics), which is used only in the "experimental" physics list FTFP_BERT_TRV. Thanks to the feedback of Anisa, we realized just today that the Gheisha elastic cross sections for deuteron, triton and alpha are actually always zero, for all energies. So the fix will be to use the Glauber-Gribov elastic cross sections for these light ions, as we are already doing since a number of years in the alternative G4HadronHElasticPhysics.
Thanks a lot for the feedback and sorry for the mistake!
Best regards, Alberto