1. Neutron production in Pb/U assembly irradiated by p+, d+ at 0. 7 – 2
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

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, 1013 total
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 known sexp
– (d,3p2n)24Na – only one value in our region
sexp= ± 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 sexp in our energy region!

7. Detection of neutrons Al Au Bi Co In Ta Reaction E thresh [MeV]
Half-life
197Au (n,2n) 196Au
8.1
6.183 d
197Au (n,3n) 195Au
14.8
 186.1 d
197Au (n,4n) 194Au
23.2
38.02 h
197Au (n,5n) 193Au
30.2
17.65 h
197Au (n,6n) 192Au
38.9
4.94 h
197Au (n,7n) 191Au
45.7
3.18 h
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
non point-like emittors
detector deadtime
detector efficiency

10. Longitudinal distributions of isotopes produced in Au and Al foils (e
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. Description of U/Pb assembly in MCNPX
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 assembly in 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. Thank you for your attention..
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 higher energies
Continue deuteron experiments
Detailed analysis of possible sources of uncertainties
 to find out “where is the problem?” 
Thank you for your attention..