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..