Implementation of an analytical model accounting for sample inhomogeneities in refit
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Implementation of an analytical model accounting for sample inhomogeneities in REFIT. K. Kauwenberghs EC – JRC – IRMM Standards for Nuclear Safety, Security and Safeguards (SN3S). Outline. Introduction (EC - JRC- IRMM) Neutron Resonance Transmission and Capture Analysis Motivation

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Implementation of an analytical model accounting for sample inhomogeneities in refit

Implementation of an analytical model accounting for sample inhomogeneities in REFIT

K. Kauwenberghs

EC – JRC – IRMM

Standards for Nuclear Safety, Security and Safeguards (SN3S)


Outline
Outline inhomogeneities in REFIT

  • Introduction (EC - JRC- IRMM)

  • Neutron Resonance Transmission and Capture Analysis

  • Motivation

  • Initial model validation

  • Experimental model validation

  • Summary


Ec jrc irmm neutron facilities

VdG inhomogeneities in REFIT

GELINA

EC - JRC – IRMMneutron facilities

JRC-IRMM major provider in Europe of ND for nuclear energy applications


Ec jrc irmm neutron facilities1
EC - JRC – IRMM inhomogeneities in REFITneutron facilities

GELINA

Van de Graaff

99Tc(n,) cross section

White neutron source

+

Time-of-flight (TOF)

Mono-energetic neutrons

(cp,n) reactions


Ec jrc irmm gelina

FLIGHT PATHS NORD inhomogeneities in REFIT

ELECTRON LINAC

TARGET HALL

FLIGHT PATHS SOUTH

EC - JRC – IRMMGELINA

  • Pulsed white neutron source

    • (10 meV < En < 20 MeV)

  • High resolution TOF measurements

  • Multi-user facility: 10 flight paths

  • Flight pathlengths: 10 m – 400m

  • Measurement stations with special equipment to perform:

    • Total cross section measurements

    • Partial cross section measurements

Mondelaers and Schillebeeckx, Notizario 11 (2006) 19


Ec jrc irmm gelina1
EC - JRC – IRMM inhomogeneities in REFITGELINA

  • e- accelerated to Ee-,max ≈ 140 MeV

  • Bremsstrahlung in U-target

    (rotating & cooled with liquid Hg)

  • (  , n) , (  , f ) in U-target

  • Low energy neutrons by moderation (water moderator in Be-canning)


Neutron resonance transmission and capture analysis

Capture inhomogeneities in REFIT

Transmission

Neutron Resonance Transmissionand Capture Analysis

T : transmission

Fraction of the neutron beam traversing the sample without any interaction

Y : capture yield

Fraction of the neutron beam creating a (n,) reaction in the sample


Neutron resonance transmission and capture analysis1
Neutron Resonance Transmission inhomogeneities in REFITand Capture Analysis

Transmission

Capture

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Neutron resonance transmission and capture analysis2
Neutron Resonance Transmission inhomogeneities in REFITand Capture Analysis

Transmission

Capture

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Neutron resonance transmission and capture analysis3
Neutron Resonance Transmission inhomogeneities in REFITand Capture Analysis

Sample out

Sample in

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Motivation good geometry homogeneous sample
Motivation inhomogeneities in REFITgood geometry + homogeneous sample

241Am

R(tm,E) response of TOF-spectrometer

REFIT, M. Moxon

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Motivation heterogeneous sample
Motivation inhomogeneities in REFITheterogeneous sample

Ignoring sample inhomogeneities:

  • Underestimation of speak

  • Overestimation of G

G


Motivation good geometry homogeneous sample1
Motivation inhomogeneities in REFITgood geometry + homogeneous sample

  • Transmission + Capture data sample properties resonance parameters


Motivation heterogeneous sample1
Motivation inhomogeneities in REFITheterogeneous sample

Expected transmission

  • Homogeneous sample:

  • Heterogeneous sample:

1cm

p(n') : distribution of areal density

From H. Uetsuka, et al., “Gamma Spectrometry of TMI-2 Debris” (written in Japanese), JAERI-Research 95-084.


Initial model validation
Initial model validation inhomogeneities in REFIT

  • Analytical models to account for inhomogeneities of a powder sample:

    • Kopecky et al. (ND2007)

    • LP Model (Levermore, Pomraninget al., J. Math. Phys. 27, 2526, 1986)

  • Comparison with transmission spectra produced by stochastic calculations (MC simulations)

  • LP model performs the best

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Initial model validation1
Initial model validation inhomogeneities in REFIT

  • Kopecky et al.:

    • Macroscopic model to describe the variation of the thickness

      Kopeckyet al., ND2007 , Nice , pp. 623 – 626; Schillebeeckxet al., NDS 113 (2012) 3054 - 3100

  • LP Model:

    • Microscopic model

      Levermore, Pomraninget al., J. Math. Phys. 27, 2526, 1986

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Experimental model validation
Experimental model validation inhomogeneities in REFIT

  • Experimental validation of the model

    = based on captureand transmission measurements at GELINA:

    • Cu powder samples with known grain size distribution

    • W powder samples with known grain size distribution

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Experimental model validation1
Experimental model validation inhomogeneities in REFIT

natW-powder mixed with natS-powder

(80 cm diameter, 14 g natW, 3.5 g natS)

natW-metal disc

(80 cm diameter, 14 g natW)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Experimental model validation2
Experimental model validation inhomogeneities in REFIT

natW-metal disc

(80 cm diameter, 14 g natW)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Experimental model validation3
Experimental model validation inhomogeneities in REFIT

natW-powder mixed with natS-powder

(80 cm diameter, 14 g natW, 3.5 g natS)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Summary
Summary inhomogeneities in REFIT

  • Model accounting for inhomogeneities of a powder sample is implemented in REFIT

  • Initialvalidation of possiblemodelswith MC simulations

    LP Model performs the best

  • Experimental validation of the model with capture and transmission measurements at GELINA

    W powder samples with known grain size distribution


Implementation of an analytical model accounting for sample inhomogeneities in refit

Contributors: inhomogeneities in REFIT

B. Becker, F. Emiliani, S. Kopecky, P. Schillebeeckx

  • EC – JRC – IRMM, Geel (B)

    H. Harada F. Kitatani, M. Koizumi, H. Tsuchiya

    JAEA, Tokai-mura (Japan)

    Acknowledgement:

    Thiswork was supportedby the European Commission within the Seventh Framework Programmethrough ERINDA (FP7 – 269499).