DEVELOPMENT AND INTEGRATION OF A FISSION EVENT GENERATOR INTO THE GEANT4 FRAMEWORK

FISSION FRAGMENT GENERATOR

Brycen L. WendtTatsumi Koi

FISSION SAMPLING

Fission Event Generation

Operation Parameters

Fission Sampling 3

FISSION EVENT GENERATION• Goal: single event perspective

• Accurately reproduce single fission event

• Maintain overall fission statistics

• Conservation

• Mass

• Momentum

• Energy

Fission Sampling 4

FISSION EVENT GENERATION1. Generate ternary fission particles

2. Select primary fission fragment

3. Generate neutrons

4. Determine secondary fission fragment

5. Sample particle energies

6. Generate fission γ’s

7. Sample angles for γ’s and neutrons

8. Sample angles for ternary particles

9. Calculate fission fragment angles

Fission Sampling 5

Fission Event Simulation

Angle/MomentumEnergyMass

Gam

ma

Tern

ary

Fiss

ion

Prod

uct

Prim

ary

Fiss

ion

Prod

uct

Neu

tron

sSe

cond

ary

Fiss

ion

Prod

uct

Sample

Sample

Sample

Sample

Sample

Sample

Sample

Sample/Calculate

Sample/Calculate

Sample/Calculate

Calculate

Calculate

Calculate/Calculate

Calculate/Calculate

Fission Sampling 6

• Geant4 kernel defines

• Fission isotope

• Fission isomer

• Incident particle

• Incident particles provide

• Fission type

• Energy

• Momentum

FISSION EVENT GENERATION

Fission Sampling 7

OPERATION PARAMETERS• File based

• Uses internal data in Geant4 neutron data files

• Maintains internal ability to parse pure ENDF data tapes

• Hard-coded values

• ν – prompt neutron production

• Ternary particle angular distributions

Fission Sampling 8

OPERATION PARAMETERS• Fission fragment sampling method

• Ternary fission

• Probability

• Yields

• Fission cause

• Spontaneous

• Neutron induced

INTEGRATION INTO GEANT4

NeutronHP

Stand-Alone Model

Integration into Geant4 10

NEUTRONHP• Two fission models available

• Activated by environment variables

• G4NEUTRONHP_PRODUCE_FISSION_FRAGMENTS• G4NEUTRONHP_USE_WENDT_FISSION_MODEL

• Selected at runtime in NeutronHPChannel

Integration into Geant4 11

NEUTRONHP• Demonstrated in example

• New in Geant4 10.1-beta

• extended/hadronic/FissionFragment

Integration into Geant4 12

STAND-ALONE MODEL• Location: neutron_hp/• Class: G4FissionFragmentGenerator• Initialized with default values

Integration into Geant4 13

STAND-ALONE MODEL• Change parameters:

• G4SetIsotope()• G4SetMetaState()• G4SetCause()• G4SetIncidentEnergy()• G4SetTernaryProbability()• G4SetAlphaProduction()• G4SetSamplingScheme()

RESULTS

Fission Fragment Production

Fission Fragment Energies

Results 15

FISSION FRAGMENT PRODUCTION

Results 16

FISSION FRAGMENT PRODUCTION

Results 17

FISSION FRAGMENT ENERGIES

FUTURE WORK

Future Work 19

FUTURE WORK• Physics

• Spontaneous fission as stand-alone model

• High energy neutron models (>10 MeV)

• Symmetric fission

• Model for fragment angular distributions

• Photo- and proton-induced fission

• Sampling model to improve fission fragment reproduction

• Utility

• Allow user-constraint on fission fragment angles

• Internal test module (test29)

Future Work 20

This research is being performed using funding received from the Integrated University Program

ACKNOWLEDGEMENTS

Appendix 21

BIBLIOGRAPHY• D. N. POENARU et al., “Multicluster accompanied fission,” Phys. Rev. C, 59, 3457 (1999).

• H. SOODAK, Reactor Handbook: Physics, John Wiley & Sons (1962).

• Z. FRAENKEL and S. G. THOMPSON, “Properties of the Alpha Particles Emitted in the Spontaneous Fission of Cf252,” Physical Review Letters, 13, 438 (1964).