M3.1 JYFL fission model

1. M3.1 JYFL fission model Department of Physics, University of Jyväskylä, FIN-40351, Finland V.G. Khlopin Radium Institute, 194021, St. Petersburg, Russia Preliminary version of the model was described in our EURISOL Research report [http://ganil.fr/eurisol]. The code FIPRODY (FIssion PRODuct Yields calculations) has been updated by inclusion advanced version of the pre-equlibrium exiton model and neutron spectra calculations. Monte Carlo method was used to simulate the time evolution of the fission process starting from the pre-equlibrium stage of reaction.

2. The code can be used for calculation folloiwing output in the proton and neutron induced reactions at energy up to 100 MeV: • Evaporation residues cross sections. • Pre-compound neutron and proton emission spectra. • Pre-compound proton and neutron multiplicity. • Pre-scission light charged particles (p, d, α) emission multiplicities. • Pre-scission neutron spectrum. • Post-scission light charged particle multiplicities. • Post-scission neutron spectrum. • Fragment kinetic energies. • Pre-neutron emission fragment mass yields. • Fission product mass yields. • Fission product yields for isobaric chains. • Fission product yields for elemental chains.

3. The two-component exciton model was used for our objectives: an adequate description of the initial excitation energy distribution and composition of the compound nuclei in the neutron and proton induced fission. For description of exciton evolution process the folloing transitions are taken into account:- proton particle-hole pair creation;- neutron particle-hole pair creation;- conversion of a proton particle-hole pair into a neutron particle-hole pair;- conversion of a neutron particle-hole pair into a proton particle-hole pair; - the proton emission;- the neutron emission;-after particle emission the exciton evolution process may develop further until reaching the criteria for transition to the compound stage of the reaction;The exciton transition cascade is ruptured at reaching one of conditions:1. exciton number reaches limited value n ≥ nmax;;2. total life time of the exciton stage exceeds limiting value Texc ≥ Tmax which corresponds to statistical width decay;3. the number of emitted particles exceeds the lemited value Mn ≥ Mnmax or Mn ≥ Mnmax .

4. M5 Netron and proton induced reactions at Fermi energy domain 232Th(p, f) at Ep = 13, 20, 40, and 55 MeV The advanced experimental setup for the multi-parameter correlation measurements consists two-arms fission fragment spectrometer CORSET, 8 DEMON neutron detectors, 3 HENDES position sensitive neutron detectors, and 12 BaF2 -detectors. Layout of detectors is shown in after next slide. Mass-kinetic energy distributions of fission fragments, double differential neutron spectra, and mean multiplicity and energy of -rays have been measured. Preliminary date are presented in the next slides. The neutron probe is important for estimations of excitation energy of compound nuclei and strength of nuclear friction. Particle emission at pre-compound and pre-scission stages influence on the conposition and excitation energy of the fissioning nucleus at the scission and on the phission product yields.

5. Experimenental setup in 232Th(p, f) experiment

10. Comparison between experimental and theoretical (red curve) neutron spectra

12. Comparison of the calculated and experimental fragment mass di´stributions

13. Average TKE of FF

14. Calculated pre-equilibrium, pre- and post-scission neutron and proton multiplicities