1. Name of Experiment:
 ------------------
 Osaka Iron Sphere Benchmark Experiment (OKTAVIAN) (1983)

2. Purpose and Phenomena Tested:
 ----------------------------
 Neutron leakage spectra from an iron sphere with a radius of 50.32 cm
 were measured by the time-of-flight technique using a 14 MeV neutron
 generator.

3. Description of the Source and Experimental Configuration:
 --------------------------------------------------------
 A Cockcroft-Walton type accelerator, OKTAVIAN of Osaka University was
 used to accelerate deuterons to a kinetic energy of 245 keV. The deuteron
 beam was led through a narrow tube to the centre of an iron sphere where
 pulsed 14.1 MeV monochromatic neutrons were produced by the d-t fusion
 reaction. The lower energy component of the source spectrum is about 5%
 of 14 MeV main component. Therefore the source is regarded to be 14 MeV
 monochromatic. The source strength is dependent on the angle (Figures  4
 and 5). The 1 m diameter iron sphere consisted of carbon steel (98.69% Fe)
 plates.

4. Measurement System and Uncertainties:
 ------------------------------------
 The detectors used were:

 Detector Diameter Thickness Energy covered
 (cm) (cm) (MeV)
 -------------------------------------------------------------------------
 NE-213 scintillator 12.7 5.08 0.07-14

 Li-6 glass scint. 12.7 2.54 0.01-1

 NE-213 scintillator 3.81 3.81 (14) neutron source monitor
 -------------------------------------------------------------------------
 Large statistical errors above about 3 MeV and below about 0.02 MeV,
 elsewhere 5 - 15%.
 Uncertainties in neutron source in 14 to 15 MeV range are about 8%.


5. Description of Results and Analysis:
 -----------------------------------
 Neutron leakage current spectrum of neutrons was measured in "absolute
 values" by the time-of-flight technique between 10 keV and 14 MeV, about
 9.5 m from the sphere centre. The energy range covers the cross section
 valley of iron at 24 keV. Because of the presence of the collimators the
 detectors could not see the entire surface of the sphere, but only the
 solid angle of 17.28 from the sphere centre.

 The experimental configuration was modelled originally in one-dimension.
 The authors found no difference in the results of ANISN calculations
 using angle dependent shell source and assuming isotropic source.
 No difference was also found between ANISN P5, S32 and P8, S64 calculations.
 The measured spectrum was found to be very sensitive to the resonant
 elastic cross-section (deep penetration neutrons) [8].
 For information, two 1-D calculational model for MCNP-4B code are provided.

 Recently a more realistic (semi) 2D model FE2d.i was developed (Ref. [9]).


6. Quality assessment:
    -----------------
 The OKTAVIAN IRON experiment seems to be of sufficient quality for nuclear
 data validation purposes.
 However, the measurements above 4 MeV should be used with caution.

 For detailed evaluation see [12].


7. Author/Organizer
 ----------------
 Experiment and analysis:
 H. Hashikura, K. Haikawa, A. Takahashi *, J. Yamamoto *, K. Kanasugi,
 Y. Oka, K. Sumita *, S. An,
 Nuclear Engineering Research Laboratory, Faculty of Engineering
 University of Tokyo
 Tokai-mura, Ibaraki 319-11, JAPAN

 * Department of Nuclear Engineering
 Osaka University
 Yamada-oka, Suita, Osaka 564, JAPAN


 Compiler of data for Sinbad:
 I. Kodeli
 OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France
 E-mail: ivan.kodeli@ijs.si

 
 Quality assessment:
 A. Milocco, Institut Jožef Stefan, Jamova 39, Ljubljana, Slovenia


 Reviewer of compiled data:
 A. Trkov
 Institute Jozef Stefan, Jamova 39, 1000 Ljubljana, Slovenia
 E-mail: andrej.trkov@ijs.si


8. Availability:
 ------------
 Unrestricted

9. References:
 ----------
    [1] K. Sumita, A. Takahashi, H. Hashikura, et al: Measurements of Neutron
        Leakage Spectra from 50.32 cm Radius Iron Sphere,
        OKTAVIAN Report A-83-07 (1983)
    [2] A. Takahashi, J. Yamamoto, H. Hashikura, et al: Experimental and
        Analytical Studies on Deep Penetration in Iron,
        OKTAVIAN Report C-84-09 (1984)
    [3] K. Sumita, A. Takahashi, H. Hashikura, et al: Measurements of Neutron
        Leakage Spectra from 50.32 cm Radius Iron Sphere, UTNL-R 0159 (1983)
    [4] A. Takahashi: Integral Neutronics Experiments at OKTAVIAN,
        OKTAVIAN Report B-83-01 (1983)
    [5] H. Hashikura, K. Haikawa, A. Takahashi, J. Yamamoto, K. Kanasugi,
        Y. Oka, K. Sumita, S. An, Neutron Leakage Spectra From a Large Iron
        Sphere Pulsed with 14 MeV Neutrons,
        NEA Specialists' Meeting on Shielding Benchmarks, Saclay, France (1984).
    [6] M. Lanfranchi, J. F. Jaeger:
        Shielding Benchmarks. Some Considerations on Three Iron Shielding
        Benchmarks, EIR Report  TM-45-86-33, NEACRP Specialists' Meeting on
        Shielding Benchmarks, Paris (Oct. 1986)
    [7] J. Hasnip, V. Herrnberger, Analysis of Fe-Shielding Benchmark
        Experiments by the JEF-1/EFF-Library,
        NEACRP Specialists' Meeting on Shielding Benchmarks, Paris (Oct. 1986)
    [8] A. Santamarina, I. Abidi, B. Gastaldi, Analysis of Fe Shield Benchmark
        Experiments and Sensitivity Studies. JEF-EFF Data Base Improvement,
        JEF-EFF Meeting, Paris (Dec. 1992)
    [9] Fujio Maekawa, FNS/JAERI, Private communication (1998)
   [10] A. Trkov, Comments on the Oktavian Iron Sphere Benchmark,
        Institute "Jozef Stefan", IJS-DP-7958 (Nov. 1998).
   [11] Yo Makita and Akito Takahashi: IAEA Benchmark Problem Based on the
        Time-of-Flight Experiment on Iron Sphere at OKTAVIAN/Osaka University,
        IAEA, http://ripcnt01.iaea.or.at/nds/databases/fendl/FENDL.htm
   [12] A. Milocco, The Quality Assessment of the OKTAVIAN Benchmark Experiments,
        IJS-DP-10214, April 2009
   [13] A. Milocco, A. Trkov, I. Kodeli: "The OKTAVIAN TOF Experiments in SINBAD:
        Evaluation of the Experimental Uncertainties",
        Annals of Nuclear Energy 37 (2010) pp. 443-449


10. Data and Format:
 ---------------

 DETAILED FILE DESCRIPTIONS
 --------------------------
 Filename Size[bytes] Content
 ---------------- ----------- -------------
  1 okfe-abs.htm    10.519 This information file
  2 okfe-exp.htm    23.867 Description of Experiment
  3 Oktavian.pdf 2,934,763 Document describing quality assessment of OKTAVIAN experiments
  4 FE2d.i           2,618 Recommended 2-D MCNP5(X) input allowing time and energy domain analysis
  5 Mcnp1.inp        7.691 1-D MCNP-4B Input by F. Maekawa (OBSOLETE-cavity & detector modeling approximations)
  6 Mcnp2.inp        9.524 3-D MCNP-4B Input by A. Trkov (OBSOLETE-cavity & detector modeling approximations)
  7 Fe-Fig1.tif     68.118 Figure 1: Plan view of the OKTAVIAN facility (high quality)
  8 Fe-Fig2.tif     60.501 Figure 2: View of the experimental arrangement (high quality)
  9 Fe-Fig3.tif     43.741 Figure 3: Iron sphere details (high quality)
 10 Fe-Fig1.gif     13.838 Figure 1: Plan view of the OKTAVIAN facility (preview)
 11 Fe-Fig2.gif     11.659 Figure 2: View of the experimental arrangement (preview)
 12 Fe-Fig3.gif      6.793 Figure 3: Iron sphere details (preview)
 13 Fe-Fig4.gif     10.626 Figure 4: Angular dependence of the neutron source (preview)
 14 Fe-Fig5.gif     13.441 Figure 5: Angular dependence of the neutron yield (preview)
 15 Fe-Fig6.gif      8.051 Figure 6: Leakage neutron spectrum (preview)
 16 Fe-Fig7.gif     20.810 Calculated vs. experimental neutron spectra - JENDL-FF (F. Maekawa- 1D model)
 17 Fe-Fig8.gif     23.581 Calculated vs. experimental neutron spectra - EFF-3.1 (A. Trkov- 1D model)
 18 OKTFE_1.pdf    690.598 Reference
 19 Oktfe_5.pdf    572.130 Reference
 20 Oktfe_8.pdf  1.090.916 Reference
 21 ane-10.pdf     585,384 Reference


 File OKFE-EXP.HTM contains the following tables:
 A table with the source neutron spectrum, and 2 tables of measured neutron
 leakage spectra (high and low energy range).

 Figures are included in TIFF format using LZW compression and GIF (preview) format .
 
 SINBAD Benchmark Generation Date: 8/2000
 SINBAD Benchmark Last Update: 2/2010