Neutron production Neutron production in Pb/U assembly in Pb/U assembly
irradiated irradiated byby pp++, d, d++ atat 0.7 – 2.52 GeV 0.7 – 2.52 GeV
Ondřej SvobodaOndřej SvobodaNuclear Physics Institute, Nuclear Physics Institute, Academy of Sciences of Academy of Sciences of
Czech RepublicCzech Republic
Department of Nuclear Reactors, Faculty of Department of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Nuclear Sciences and Physical Engineering,
Czech Technical University in PragueCzech Technical University in Prague
svobodasvoboda@@ujf.cas.cujf.cas.czz
OutlineOutline• Energy plus Transmutation projectEnergy plus Transmutation project• Proton and deuteron experimentsProton and deuteron experiments• MCNPX simulationsMCNPX simulations• Experiment Experiment Simulation Simulation• ConclusionConclusion
Energy plus Energy plus Transmutation projectTransmutation project
• Main aim: study of transmutation of FP Main aim: study of transmutation of FP and HA by spallation neutronsand HA by spallation neutrons
• Our tasks: Our tasks: o study of neutron production in thick, heavy study of neutron production in thick, heavy
target with fissionable blanket irradiated target with fissionable blanket irradiated by light ions in GeV rangeby light ions in GeV range
o pperform relevant Monte-Carlo simulationserform relevant Monte-Carlo simulationso mmake cake comparisonomparisonss between experimental between experimental
datadata and simulations and simulations
Energy plus Transmutation Energy plus Transmutation - setup- setup
Proton and dProton and deuteron euteron eexperimentxperimentss
• Until now :Until now : - p- p++ experiments – energies 0.7, 1, 1.5 experiments – energies 0.7, 1, 1.5,, and 2 and 2 GeV GeV Analyzed & simulated Analyzed & simulated
- - dd++ experiments experiments - energies 1.6 - energies 1.6 and and 2.52 GeV2.52 GeV Preliminary results, simulations in Preliminary results, simulations in
progressprogress
• On On Nuclotron accelerator Nuclotron accelerator ((JJoint oint IInstitute for nstitute for NNuclear uclear RResearch,esearch, Dubna, Russia) Dubna, Russia)
• Intensity Intensity ~~ 10101100/b/bunchunch, 10, 101313 totaltotal• Irradiation time: Irradiation time: about about 8 h8 h
DDeuterons represent a new challenge for us – euterons represent a new challenge for us – difficulties both in experiment and in difficulties both in experiment and in simulation!simulation!
27Al(d,3p2n)24Na
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
1 10 100 1000 10000
Deuteron energy [MeV]
cro
ss
-se
cti
on
[b
]
our region
Beam Beam monitorsmonitors
• 2727Al beam monitor –Al beam monitor – ((pp,3pn),3pn)2424NaNa – – well knownwell known expexp
–– (d,3p2n)(d,3p2n)2424NaNa – – only only one one value in our value in our regionregion
expexp= = 15.25 15.25 ±± 1.50 mbarn (2330 MeV) 1.50 mbarn (2330 MeV)
• natnatCu beam monitor – Cu beam monitor – (p,X) – many (p,X) – many isotopes isotopes 5858Co, Co, 5656Co, Co, 5555Co, Co, 5252Mn, Mn, 4848Cr, Cr, 4848Sc, Sc, 44m44mSc, Sc, 5757Ni, Ni, 4848V, V, 4343K, K, 6161Cu, Cu, etc. – etc. – well well known known expexp
– – (d,X) – (d,X) – no no expexp in our energy region!in our energy region!
σANx
NN
A
yieldd
)isotope(
Detection Detection of of neutronsneutrons
ReactionE thresh [MeV]
Half-life
197Au (n,2n) 196Au
8.1 6.183 d
197Au (n,3n) 195Au
14.8 186.1
d197Au (n,4n)
194Au23.2 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
Al Au Bi
Co In
Ta
EXFOR data
Placement of activation foilsPlacement of activation foils
Gamma spectra measurement and Gamma spectra measurement and evaluationevaluation
• Yields of produced isotopes computed Yields of produced isotopes computed with respect to all corrections:with respect to all corrections:
- decay during decay during cooling, cooling, measurement, measurement, irradiationirradiation
- unequable unequable irradiationirradiation
- coincidences coincidences
- nonnon pointpoint-like-like emiemitttorstors
- detector detector deadtimedeadtime
- detector detector efficiencyefficiency
Longitudinal distributions of Longitudinal distributions of isotopes produced in Au and Al foils isotopes produced in Au and Al foils
((e.g., 2.52 GeV deuterons)
1E-06
1E-05
1E-04
1E-03
-5 0 5 10 15 20 25 30 35 40 45 50Position along the target [cm]
Yie
ld [
1/(
g*d
eu
tero
n)]
198Au 196Au 194Au 192Au 24Na
10-5
10-4
10-3
10-6
Radial distributions of isotopes Radial distributions of isotopes produced in Au and Al foils produced in Au and Al foils ((e.g.,
2.52 GeV deuterons)
1E-07
1E-06
1E-05
1E-04
1E-03
2 4 6 8 10 12Radial distance from the target axis [cm]
Yie
ld [
1/(g
*deu
tero
n)]
198Au 196Au 194Au193Au 192Au 24Na
10-3
10-4
10-5
10-6
10-7
Simulations – MCNPX 2.6.Simulations – MCNPX 2.6.CCDifferent 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 modelsDescription Description
of of U/Pb U/Pb
assemblyassembly inin MCNPX MCNPX
Experiment versus Experiment versus Simulations – models Simulations – models
comparisoncomparisonexample of 194Au in radial distribution, 1 GeV proton
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 3 6 9 12Radial position from the target axis [cm]
exp
. yie
ld /
sim
. yie
ld
Bertini+ABLA CEM03Liege+ABLA Liege+DresnerIsabel+ABLA Isabel+DresnerBertini+Dresner
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15Radial distance from target axis [cm]
exp
. yie
ld /
sim
. yie
ld
2.0 GeV
1.5 GeV
1.0 GeV
0.7 GeV
Experiment versus SimulationsExperiment versus Simulationsrelative ratios of experimental and simulated yields (normalized to this foil)
MCNPX setting: Bertini + Dresner
SummarySummary• Experiment × simulation:Experiment × simulation:
• ProtonProtons – s – good agreement for EEp p ≤ 1 GeV –– big difference for EEpp ≥ 1.5 GeV
• DeuteronDeuteronss – experiment analysis – experiment analysis in progressin progress – simulations problematic, only – simulations problematic, only
INCL4 can simulate EE >2 GeV, but very >2 GeV, but very time consuming time consuming
• Future plans: Future plans: • PPerform proton experiments with highererform proton experiments with higher energiesenergies• Continue Continue ddeuteron experimentseuteron experiments• Detailed analysis of possible sources of uncertainties Detailed analysis of possible sources of uncertainties
to find out “to find out “where is the where is the problem?” problem?”
Thank you for your attention..