Hello,
yes, FTFP_BERT_HP and QGSP_BERT_HP physics lists, in Geant4 11.2 (and patches) do not have the same “HP” (i.e. treatment of neutrons with kinetic energy below 20 MeV). This unexpected behaviour is due to the fact that in 11.2 we have included a first round of revisions of the HP package: all the “technical” changes - that are not supposed to affect any physics observable - are common to all the HP-based physics lists; some changes that might affect physics observables have been included only on the QGSP_BERT_HP physics list. The choice of this physics list was motivated by the fact that those changes in HP are preliminary and still need extensive validation, therefore we decided to include them only in one HP-based physics list, the one that is less used by users (to the best of our knowledge). Given the preliminary nature of these changes, we did not put much emphasis in the release notes of G4 11.2, although there is the following statement:
“G4NeutronHPCaptureXS, G4NeutronHPElasticXS, G4NeutronHPInelasticXS, G4NeutronHPFissionXS, G4CrossSectionHP, G4NeutronFissionVI, G4NeutronRadCaptureHP: updated models and cross-sections which are included only in the physics list QGSP_BERT_HP”.
The result reported result seems to show that there is some bug or issue in the HP version included in QGSP_BERT_HP.
We will investigate it - but in the meantime, please use another HP-based physics list (e.g. FTFP_BERT_HP) for your simulations.
Thanks a lot for the feedback, and apologies for the unexpected feature of QGSP_BERT_HP, certainly not documented very clearly in our release notes!