There is no neutron production in simulation for DD reaction in Hadr03

hi dear experts,

I’ve been trying to simulate DD and DT fusion with Hadr03 Example.
despite the approximately same cross-section between DD and DT fusion at 900keV, there is no neutron production in simulation for DD reaction.

this is the output for DT fusion

The run is 100000 deuteron of 900 keV through 100 km of tritium (density: 5 mg/cm3)

Process calls frequency:
dInelastic= 100000

MeanFreePath: 37.887 m ± 38.049 m massic: 18.943 g/cm2
CrossSection: 0.00026395 cm^-1 massic: 5.2789 mm2/g
crossSection per atom: 264.41 mbarn

Verification: crossSections from G4HadronicProcessStore:
dInelastic= 5.292 mm2/g 265.07 mbarn
total= 5.292 mm2/g 265.07 mbarn

List of nuclear reactions:

                    deuteron + tritium --> neutron + alpha:  100000   Q =   17.59 MeV

List of generated particles:
alpha: 100000 Emean = 3.9554 MeV ( 1.9056 MeV → 6.01 MeV)
neutron: 100000 Emean = 14.534 MeV ( 12.48 MeV → 16.584 MeV)

and this output for DD fusion

The run is 100000 deuteron of 900 keV through 100 km of deuteron (density: 5 mg/cm3)

Process calls frequency:
dInelastic= 100000

MeanFreePath: 40.176 m ± 40.348 m massic: 20.088 g/cm2
CrossSection: 0.00024891 cm^-1 massic: 4.9782 mm2/g
crossSection per atom: 166.49 mbarn

Verification: crossSections from G4HadronicProcessStore:
dInelastic= 4.9905 mm2/g 166.91 mbarn
total= 4.9905 mm2/g 166.91 mbarn

List of nuclear reactions:

                        deuteron + deuteron --> 2 deuteron:   94661   Q = 0.00025005 meV
             deuteron + deuteron --> N gamma or e- + alpha:    5339   Q =  23.847 MeV

                      number of gamma or e- (ic): N = 1 --> 2

List of generated particles:
alpha: 5339 Emean = 519.56 keV ( 151.2 keV → 900.77 keV)
deuteron: 189322 Emean = 450 keV ( 20.53 eV → 899.98 keV)
gamma: 6386 Emean = 20.255 MeV ( 4.0223 MeV → 24.596 MeV)

can Geant4 simulate DD fusion?
am I should use another physicsList for DD fusion?

this is cross-section of these fusions

Ongena, J., 2015. Fusion: A true challenge for an enormous reward. In EPJ Web of Conferences (Vol. 98, p. 05004). EDP Sciences.

I’m using Geant4 11.0

I run the same simulation but with QGSP_BIC_AllHP as phisycList for DT reaction and here is the output :

The run is 10000000 deuteron of 900 keV through 1 km of H3 (density: 5 mg/cm3 )

Process calls frequency:
dInelastic= 4592968 hadElastic= 5407032

MeanFreePath: 1.1866 cm ± 1.1861 cm massic: 8.6737 g/cm2
CrossSection: 0.84278 cm^-1 massic: 11.529 mm2/g
crossSection per atom: 577.47 mbarn

Verification: crossSections from G4HadronicProcessStore:
dInelastic= 5.292 mm2/g 265.07 mbarn
hadElastic= 6.2369 mm2/g 312.4 mbarn
total= 11.529 mm2/g 577.47 mbarn

List of nuclear reactions:

                       deuteron + H3 --> deuteron + triton: 5407032   Q = 0.00031846 meV
                         deuteron + H3 --> neutron + alpha: 4592968   Q =   17.59 MeV

List of generated particles:
alpha: 4592968 Emean = 3.9581 MeV ( 1.9055 MeV → 6.0101 MeV)
neutron: 4592968 Emean = 14.531 MeV ( 12.48 MeV → 16.584 MeV)
triton: 5407032 Emean = 422.27 keV ( 447.98 meV → 864.28 keV)

Momentum balance: Pmean = 0.027052 meV ( 0 eV → 34.528 meV)

Thibault