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svoboda @ ujfs.cz

Neutron production in Pb/U assembly irradiated by p + , d + at 0.7 – 2.52 GeV Ondřej Svoboda Nuclear Physics Institute, Academy of Sciences of Czech Republic Department of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague.

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svoboda @ ujfs.cz

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  1. Neutron production in Pb/U assembly irradiated byp+, d+at 0.7 – 2.52 GeVOndřej SvobodaNuclear Physics Institute, Academy of Sciences of Czech RepublicDepartment of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague svoboda@ujf.cas.cz

  2. Outline • Energy plus Transmutation project • Proton and deuteron experiments • MCNPX simulations • Experiment  Simulation • Conclusion

  3. Energy plus Transmutation project • Main aim: study of transmutation of FP and HA by spallation neutrons • Our tasks: • study of neutron production in thick, heavy target with fissionable blanket irradiated by light ions in GeV range • perform relevant Monte-Carlo simulations • make comparisons between experimental data and simulations

  4. Energy plus Transmutation - setup

  5. Proton and deuteron experiments • Until now : - p+ experiments – energies 0.7, 1, 1.5, and 2 GeV Analyzed & simulated  - d+ experiments - energies 1.6 and 2.52 GeV Preliminary results, simulations in progress • On Nuclotron accelerator (Joint Institute for Nuclear Research, Dubna, Russia) • Intensity ~1010/bunch, 1013total • Irradiation time: about 8 h Deuterons represent a new challenge for us – difficulties both in experiment and in simulation!

  6. Beam monitors • 27Al beam monitor –(p,3pn)24Na – well knownsexp –(d,3p2n)24Na – only one value in our region sexp= 15.25 ± 1.50 mbarn (2330 MeV) • natCu beam monitor – (p,X) – many isotopes 58Co, 56Co, 55Co, 52Mn, 48Cr, 48Sc, 44mSc, 57Ni, 48V, 43K, 61Cu, etc. – well known sexp– (d,X) – no sexpin our energy region!

  7. Al Au Bi Co In Ta Detection of neutrons EXFOR data

  8. Placement of activation foils

  9. Gamma spectra measurement and evaluation • Yields of produced isotopes computed with respect to all corrections: • decay during cooling, measurement, irradiation • unequable irradiation • coincidences • nonpoint-like emittors • detector deadtime • detector efficiency

  10. Longitudinal distributions of isotopes produced in Au and Al foils (e.g., 2.52 GeV deuterons)

  11. Radial distributions of isotopes produced in Au and Al foils (e.g., 2.52 GeV deuterons)

  12. Simulations – MCNPX 2.6.C • Different models available in the code – a lot of combinations! • IntraNuclear Cascade stage:Bertini, Isabel, INCL4, CEM03 models • Pre-equilibrium stage: Multistage Pre-equilibrium Exciton model • Evaporation/fission: Dresner, ABLA models Description of U/Pb assemblyin MCNPX

  13. Experiment versus Simulations – models comparison example of 194Au in radial distribution, 1 GeV proton

  14. Experiment versus Simulations relative ratios of experimental and simulated yields (normalized to this foil) MCNPX setting: Bertini + Dresner

  15. Summary • Experiment × simulation: • Protons – good agreement for Ep ≤ 1 GeV– big difference for Ep ≥ 1.5 GeV • Deuterons– experiment analysis in progress – simulations problematic, only INCL4 can simulate E>2 GeV, but very time consuming • Future plans: • Perform proton experiments with higherenergies • Continue deuteron experiments • Detailed analysis of possible sources of uncertainties  to find out “where is the problem?”  Thank you for your attention..

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