SINBAD ABSTRACT NEA-1553/26
SINBAD ABSTRACT NEA-1517/89
ENDF/B-VI Cross-Section Validation/MCNP - Validation
1. Name of Experiment: University of Illinois Iron Sphere Benchmark (1975) 2. Purpose and Phenomena Tested: The purpose of this experiment was to compare measurements and calculations of fast-neutron leakage spectra from a spherical shell of iron to test the validity and accuracy of the neutron cross-section data. 3. Description of the Source and Experimental Configuration: Two sources were used: (1) a californium-252 spontaneous fission source, and (2) a D-T fusion neutron source provided by a neutron generator. For the measurements using the D-T source, the flight tube of the neutron generator was inserted through a 9.5 cm diameter re entrant hole. For the measurements using the Cf-252 source, the reentrant hole was plugged with a steel cylinder, and the Cf-252 source was hung from a small steel holder attached to the plug. The holder positioned the Cf-252 source at the center of the iron sphere. The iron sphere and the neutron detector were both situated 1 meter above the concrete floor with the detector positioned 200 cm from the center of the sphere. The iron sphere contained 0.21% by weight of carbon and 0.47% by weight of manganese. The spherical shell of iron had an inner radius of 7.65 cm, an outer radius of 38.10 cm, and a number density of 0.0849 nuclei/barn-cm. 4. Measurement System and Uncertainties: The neutron spectrum measurements were made with a 5 cm x 5 cm glass-encapsulated NE-213 scintillator. The proton-recoil spectrometry system was chosen because it does not require an elaborate pulsed neutron source. The total estimated systematic error in the normalization of the measurements is 8% standard deviation for a Cf-252 source within the iron spherical shell. 5. Description of Results and Analysis: The energy range between 1.0 and 15 MeV was covered by the NE-213 scintillator. Background contributions to the recoil spectra were measured by placing a paraffin shadow cone midway between the detector and the spherical assembly. The spectra were unfolded by the FORIST computer code, which is a modified version of the COOLC and FERDoR computer codes. These modifications resulted in unfolded spectra having optimized energy resolution and increased accuracy through the use of an iterative smoothing technique. The ANISN one-dimensional discrete ordinates neutron transport code was used to calculate the leakage spectra. 6. Special Features: None 7. Author/Organizer: Experiment and Analysis: Richard Harold Johnson, Nuclear Engineering Program, University of Illinois at Urbana-Champaign, Urbana, IL Compiler of data for SINBAD: Jennifer Parsons, Radiation Shielding Information Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6362 Reviewer of compiled data: Hamilton Hunter, Radiation Shielding Information Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6362, fax 423-574-6182, e-mail h3o@ornl.gov 8. Availability: Unrestricted 9. References: [1] R.H. Johnson, "Integral Tests of Neutron Cross Sections for Iron, Nobium, Beryllium, and Polyethylene," PhD Thesis, University of Illinois at Urbana- Champaign (1975) [2] N.E. Hertel, R.H. Johnson, B.W. Wehring, and J.J. Dorning, "Transmission of Fast Neutrons Through an Iron Sphere," Fusion Technology, 9, 345-361 (Mar 1986) [3] M.L. Williams, C. Aboughantous, M. Asgari, J.E. White, R.Q. Wright and F.B.K. Kam, "Transport Calculations of Neutron Transmission Through Steel Using ENDF/B-V, Revised ENDF/B-V, and ENDF/B-VI Iron Evaluations," Annual Nuclear Energy, 18, 549-565 (1991) [4] D.T. Ingersoll, "Integral Testing of Neutron Cross Sections Using Simultaneous Neutron and Gamma-Ray Measurements," PhD Thesis, University of Illinois at Urbana-Champaign (1977) [5] N.E. Hertel, "High-Energy Neutron Transport Through Tungsten and Iron," PhD Thesis, University of Illinois at Urbana-Champaign (1979) 10. Data and Format: Tables: (1) 47-group Cf-252 fission spectrum (2) 199-group CF-252 fission spectrum (3) 47-group D-T source (5% D-D) (4) 199-group D-T source (5% D-D) (5) Physical Properties of the Iron Spherical Shell (6) Leakage Spectrum from the Iron Sphere containing D-T source Figures: (1) Physical Arrangement for the iron sphere (2) Background Contributions Layout (3) Leakage Spectra for Cf-252 source in iron sphere (4) Leakage Spectra for D-T source in iron sphere Document is HTML v.3.02 Format with ASCII Tables and Figures in GIF format. SINBAD Abstract Generation Date: 06/98 SINBAD Abstract Last Update: 08/06