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 1. Name of experiment:
    TUD/FNG measurement of neutron and photon flux spectra in the FNG tungsten
    assembly (2002).

 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 W 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. Note that these figures were obtained using the obsolete
    D-T source subroutine (source.for) and may vary slightly from those of
    the new recommended subroutine (DT_MCNP5.TXT for MCNP5, source.F and
    srcdx.F for MCNPX).
    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
    W alloy block were 47 cm * 47 cm * 49 cm of length (z-axis). The tritium
    target of the neutron source was located at z = -5.3 cm.
    The W alloy of the central part had a density of 18.1 g/cm3 and an elemental
    composition of 95 wt-% of W, 1.6 wt-% of Fe and 3.4 wt-% of Ni.

    Neutron and photon flux spectra were measured on the central axis of
    the assembly in four positions (P1,...,P4) at z = 5, 15, 25 and 35 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 2 in Fig. 3), the other ones were filled with rods of W

    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]. 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. [6].

    For the activation foil and TLD measurements on the same Tungsten block see
    FNG Tungsten Experiment.

 6. Quality assessment:
    The TUD/FNG TUNGSTEN experiment could be ranked as benchmark quality
    experiment, provided that supplementary experimental information is
    available on:
    – realistic and complete estimation of neutron and gamma flux point–wise
    - availability of the original pulse-height distributions measured by
      spectrometers and the detector geometry would be useful for those who
      wish to carry out their own spectra unfolding,
    - some inconsistencies observed with the FNG-W benchmark results should
      be explained and resolved.

    For detailed evaluation see Ref. [8].

 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, D. Leichtle
    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
    Quality assessment:
    A. Milocco, Institut Jožef Stefan, Jamova 39, Ljubljana, Slovenia
    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] H. Freiesleben, C. Negoita, K. Seidel, S. Unholzer, U. Fischer, D.
        Leichtle, M. Angelone, P. Batistoni, M. Pillon, "Measurement and
        analysis of neutron and gamma-ray flux spectra in Tungsten",
        Report TUD-IKTP/01-03, Dresden, EFFDOC-857 (2003)
    [7] U. Fischer et al., Monte Carlo Transport and Sensitivity Analyses
        for the TUD Neutron Transport Benchmark Experiment on Tungsten,
        EFFDOC-860 (2002)
    [8] A. Milocco, The Quality Assessment of the FNG/TUD Benchmark Experiments,
        IJS-DP-10216, April 2009
    [9] A. Milocco, A. Trkov, MCNPX/MCNP5 Routine for Simulating D–T Neutron
        Source in Ti-T Targets, IJS-DP-9988, July 2008

10. Data and Format:


No.  File name     Size (kB)     Content
     ------------- --------- ---------------
 1  tudw-a.htm      11,751  This abstract
 2  tudw-e.htm      42,286  Description of experiment
 3  tudw-c.htm      15,189  Description of transport calculations
 4  FNG-TUD.pdf    221,831  Document describing the quality assessment of the
                            FNG and TUD benchmarks
 5  D-T.pdf        493,108  Document describing the D–T source routine for MCNPX(5)
 6  DT_MCNP5.TXT    51,672  Patch with MCNP5 source subroutines for the calculation
                            of 14-MeV D-T source (new release)
 7  source.F        29,688  source.F subroutine for MCNPX-2.6f to calculate 14-MeV
                            D-T source (new release)
 8  srcdx.F         12,709  srcdx.F subroutine for MCNPX-2.6f containing also 
                            subroutines for numerics  to calculate 14-MeV D-T
                            source (new revised version)
 9  source.for      39,959  FNG D–T source routine for MCNP4C (obsolete)
10  mcnp.inp        36,252  3-D model for MCNP-4C code
11  fig1.jpg        27,072  Fig. 1: Angular dependence of the neutron source
12  fig2.jpg        50,616  Fig. 2: Neutron source energy/angular distribution
13  fig3.jpg        24,793  Fig. 3: Geometry of the assembly
14  fig4.jpg        31,016  Fig. 4: Neutron spectra at position P-1
15  fig5.jpg        31,869  Fig. 5: Neutron spectra at position P-2
16  fig6.jpg        31,057  Fig. 6: Neutron spectra at position P-3
17  fig7.jpg        32,138  Fig. 7: Neutron spectra at position P-4
18  fig8.jpg        32,047  Fig. 8: Gamma-ray spectra at position P-1
19  fig9.jpg        32,657  Fig. 9: Gamma-ray spectra at position P-2
20  fig10.jpg       33,364  Fig. 10: Gamma-ray spectra at position P-3
21  fig11.jpg       32,926  Fig. 11: Gamma-ray spectra at position P-4
22  eff-857.pdf    290,424  Reference [6] EFFDOC-857
23  eff-860.pdf  1,067,715  Reference [7] EFFDOC-860

    Files tudw-e.htm and tudw-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: 2/2010