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 1. Name of experiment:
    TUD measurement of neutron and photon flux spectra in a silicon carbide         
    assembly (2001).

 2. Purpose and phenomena tested:
    Transport data benchmark by determination of spectral neutron flux and 
    spectral photon flux at four positions in a thick block of SiC irradiated   
    with 14 MeV neutrons.  

 3. Description of source and experimental configuration:
    The Frascati Neutron Generator [1] was used as 14 MeV D-T neutron
    source. The angular dependence of the source intensity is presented in
    Fig. 1. The angular dependence of the source energy distribution is
    given in Fig. 2.

    The geometry of the assembly is shown in Fig. 3. The angle between the
    deuteron beam of the neutron generator and an axis crossing neutron 
    source and centre of the detector was 0 degrees. The dimensions of the   
    SiC block, composed of bricks, were 45.7 cm * 45.7 cm * 71.1 cm of length
    (x-axis). The tritium target of the neutron source was located at 
    z = -5.3 cm. The SiC material was described in the calculations with a
    density of 3.158 g/cm3 and an elemental composition of 68.9 wt-% of Si,
    30.8 wt-% of C, 0.19 wt-% of B, 0.079 wt-% of Al, and 0.014 wt-% of Fe. 

    The information on the concentration and heterogeneity of Boron may not
    be reliably. B-10 content strongly influences the thermal neutron flux
    and consequently the (n,gamma) reactions (e.g. gamma peak at 0.48 MeV from
    thermal neutron capture in B-10).

    Neutron and photon flux spectra were measured on the central axis of   
    the assembly at four positions (P1,...,P4) at x = 12.70, 27.94, 43.18 and                   
    58.42 cm.

    4. Measurement system:
    Neutron and photon pulse-height spectra were measured simultaneously 
    using an NE 213 scintillation spectrometer. The dimensions of the 
    cylindrical active volume of the detector were 3.8 cm in both height 
    and diameter. Its material had a mass density of 0.874 g/cm3 and an 
    elemental composition of 54.8 at-% H and 45.2 at-% C.
    The scintillator was coupled to a photomultiplier by means of a 50 cm 
    long light guide. When the detector was located at one of the 
    positions (P 1 in Fig. 3), the other ones were filled with pieces of SiC.

    5. Description of results and analysis:
    Data evaluation:
    The DIFBAS code developed at PTB Braunschweig [2,3] was employed for     
    unfolding the measured pulse-height distributions in order to generate 
    the neutron and photon flux spectra. They were obtained as absolute 
    fluxes, as the response matrices have been determined on an absolute 
    scale by detailed simulations of experimental distributions from mono-
    energetic neutron and photon sources with Monte Carlo codes.

    A computational analysis was performed with the Monte Carlo code MCNP-
    4C [4] using a full 3D model of the assembly, the neutron generator and 
    the experimental hall. Nuclear data were taken from the FENDL/MC-2.0 
    data library [5] except for Si-28, for which EFF-3.0 [6] data were used.
    The spectra were calculated as average flux in the scintillator volume by
    means of the track length estimator of MCNP.

    Results are shown in Figs. 4, 5, 6, 7, 8, 9, 10 and 11. More details
    are given in Ref. [7].

    For the activation foil and TLD measurements on the same SiC block see
    FNG Silicon Carbide Experiment.

 6. Special features:

 7. Authors/Organizer:
    Experiment and analysis:

    K. Seidel, H. Freiesleben, C. Negoita, S. Unholzer
    Technische Universitaet Dresden
    Institut fuer Kern- und Teilchenphysik
    D-01062 Dresden

    U. Fischer, Y. Chen, R. L. Perel
    Forschungszentrum Karlsruhe
    Institut fuer Reaktorsicherheit
    D-76021 Karlsruhe

    M. Angelone, P. Batistoni, M. Pillon 
    Associazione ENEA-EURATOM
    Settore Fusione - Divisione Neutronica
    Via E. Fermi 27
    I-00044 Frascati (Rome) 

    Compiler of data for Sinbad:
    K. Seidel
    Technische Universitaet Dresden
    Institut fuer Kern- und Teilchenphysik
    D-01062 Dresden, Germany

    Reviewer of compiled data:
    I. Kodeli
    OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France

 8. Availability:

 9. References:

    [1] M. Angelone, M. Pillon, P. Batistoni, M. Martini, M. Martone, V. 
        Rado, "Absolute experimental and numerical calibration of the 14 
        MeV neutron source at the Frascati Neutron Generator", Rev. Sci. 
        Instr. 67(1996)2189. 
    [2] M. Tichy, "The DIFBAS Program - Description and User's Guide",   
        Report PTB-7.2- 193-1, Braunschweig 1993.
    [3] S. Guldbakke, H. Klein, A. Meister, J. Pulpan, U. Scheler, M. 
        Tichy, S. Unholzer, "Response Matrices of NE213 Scintillation 
        Detectors for Neutrons", Reactor Dosimetry ASTM STP 1228, Ed. H. 
        Farrar et al., American Society for Testing Materials, 
        Philadelphia, 1995, p. 310.
    [4] J. F. Briesmeister (Ed.), "MCNP - A general Monte Carlo n-particle
        transport code", version 4C, Report LA-13709, Los Alamos National 
        Laboratory, 2000.
    [5] H. Wienke, M. Herman, "FENDL/MG-2.0 and FENDL/MC-2.0 - The 
        processed cross section libraries for neutron and photon transport 
        calculations", Report IAEA-NDS-128, Vienna, 1998.
    [6] S. Tagesen, H. Vonach, "Evaluation of neutron cross sections for
        fusion relevant materials", EFFDOC-785, NEA Data Bank, Nov. 2001. 
    [7] H. Freiesleben, C. Negoita, K. Seidel, S. Unholzer, Y. Chen, U.  
        Fischer, R. L. Perel, M. Angelone, P. Batistoni, M. Pillon,                         
        "Measurement and analysis of neutron and gamma-ray flux spectra in  
        Tungsten", Report TUD-IKTP/02-02, Dresden, 2002, EFFDOC-822.
    [8] U. Fischer, R. Perel and Y. Chen, Monte Carlo Transport, Sensitivity
        and Uncertainty Analyses for the TUD Benchmark Experiment on SiC,
    [9] K. Seidel, M. Angelone, P. Batistoni, Y. Chen, U. Fischer, H.        
        Freiesleben, C. Negoita, R. L. Perel, M. Pillon, S. Unholzer, 
        Measurement and Analysis of Neutron and Gamma-Ray Flux Spectra in Sic
        Fus. Eng. Design 69 (2003) 379.
   [10] Y. Chen, U. Fischer, I. Kodeli, R. L. Perel, M. Angelone, P. Batistoni,
        L. Petrizzi, K. Seidel, S. Unholzer, Sensitivity and uncertainty
        analyses of 14 Mev neutron benchmark experiment on Silicon Carbide,
        Fus. Eng. Design 69 (2003) 437-442.

10. Data and Format:


No.  File name     Size (kB)   Content
     ------------- ---------   ---------
 1  tudsic-a.htm     12,313    This abstract
 2  tudsic-e.htm     41,669    Description of experiment
 3  tudsic-c.htm     13,557    Description of transport calculations
 4  mcnp.inp         20,360    3-D model for MCNP-4C code
 5  source.for       39,959    FORTRAN subroutine for MCNP source description
 6  fig1.jpg         27,072    Fig. 1: Angular dependence of the neutron source
 7  fig1.ps          71,157    Fig. 1 (ps format)
 8  fig2.jpg         50,616    Fig. 2: Neutron source energy/angular distribution
 9  fig2.ps         850,273    Fig. 2 (ps format)
10  fig3.jpg         24,883    Fig. 3: Geometry of the assembly
11  fig3.ps          27,754    Fig. 3 (ps format)
12  fig4.jpg         33,108    Fig. 4: Neutron spectra at position P-1
13  fig4.ps          27,643    Fig. 4 (ps format)
14  fig5.jpg         32,832    Fig. 5: Neutron spectra at position P-2
15  fig5.ps          28,006    Fig. 5 (ps format)
16  fig6.jpg         32,204    Fig. 6: Neutron spectra at position P-3
17  fig6.ps          27,654    Fig. 6 (ps format)
18  fig7.jpg         33,119    Fig. 7: Neutron spectra at position P-4
19  fig7.ps          27,612    Fig. 7 (ps format)
20  fig8.jpg         33,662    Fig. 8: Gamma-ray spectra at position P-1
21  fig8.ps          26,254    Fig. 8 (ps format)
22  fig9.jpg         34,696    Fig. 9: Gamma-ray spectra at position P-2
23  fig9.ps          26,456    Fig. 9 (ps format)
24  fig10.jpg        32,920    Fig. 10: Gamma-ray spectra at position P-3
25  fig10.ps         26,351    Fig. 10 (ps format)
26  fig11.jpg        35,094    Fig. 11: Gamma-ray spectra at position P-4
27  fig11.ps         26,654    Fig. 11 (ps format)
28  eff-822.pdf     123,534    Reference [7] EFFDOC-822
29  eff-815.pdf   1,008,339    Reference [8] EFFDOC-815
30  soft22j39.pdf    71,152    Reference [9]
31  soft-22.pdf     236,191    Reference [10]

    Files tudsic-e.htm and tudsic-c.htm contain the following tables:

Tab. 1: Angular dependence of the source
Tab. 2: Angular dependence of the source energy distribution 
Tab. 3: Spectral neutron fluences for P1...P4, experiment
Tab. 4: Uncertainties of the measured neutron fluences
Tab. 5: Spectral photon fluences for P1...P4, experiment
Tab. 6: Uncertainties of the measured photon fluences
Tab. 7: Spectral neutron fluences for P1...P4, calculation
Tab. 8: Spectral photon fluences for P1...P4, calculation

    The figures describing the geometry of the experiment and the
    spectral fluences are included as PostScript and jpg files.

SINBAD Benchmark Generation Date: 4/2004
SINBAD Benchmark Last Update: 4/2004