SINBAD ABSTRACT NEA-1517/58
SBE 1.008

 
1. Name of Experiment
  
SDT1. Iron Broomstick Experiment - An Experimental Check of Neutron Total Cross
Sections - 1968

2. Purpose and Phenomena Tested:  
 
This experiment was designed to test a given set of neutron total cross sections for
iron in the range of 0.8 - 11 MeV.
  
3. Description of the Source and Experimental Configuration:  

The source used was the Tower Shielding Reactor II (TSRII) at the Tower Shielding 
Facility located in Oak Ridge National Laboratory. A 3.5-inch-beam of neutrons 
emerged from the 4-inch-collimator made of water and lithiated paraffin. The 8 and 
12 inch samples of iron were placed approximately 50 feet away, lengthwise in the 
neutron beam and housed behind a 4-foot-thick water shield with a 3.5-inch-diameter 
hole concentric to the beam and iron samples. The detector was placed approximately 
50 feet behind the sample and well shielded with water and lead. The purpose for the
distance is to minimize in scattered neutrons mixing with the uncollided neutron 
spectrum.
  
4. Measurement System and Uncertainties:  
 
The measurements were made with a NE-213 spectrometer, with a 2 in. x 2 in. active 
fluid cylinder. A modified Forte circuit separated the neutron from the gamma-
induced pulses. Unfolding the pulse-height distributions was accomplished by using 
the FERDoR computer code. The data uncertainty is due to statistical collections and
a 5-10% error in power calibration. The data is unfolded into a 68% uncertainty 
range (high and low) for flux values, excluding the power calibration error.

5. Description of Results and Analysis:  

The data was collected for a bare beam, (iron sample removed) to collect a source 
spectrum, for use in the calculated uncollided spectrum. Data was then collected for
a 8-inch-long x 4-inch-diameter iron sample and a 12-inch-long x 4-inch-diameter 
iron sample. The density of the samples was 0.0847 atoms/barn-cm and considered to 
be 100% Iron. 
  
6. Special Features:

None
  
7. Author/Organizer  

Experiment:
    C.E. Clifford, E.A. Straker, F.J. Muckenthaler, V.V. Verbinski, R.M. Freestone, 
    Jr., K.M. Henry, and W.R. Burrus, 1967
  
Analysis:
    R.E. Maerker ORNL TM 3867 (in reference to E.A. Straker ORNL TM 2242)
 
Compiler of data for SINBAD: 
    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.
  
Reviewer of compiled data: 
    C.O. Slater, Nuclear Analysis and Shielding Section, Computational Physics and 
    Engineering Division, Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge, 
    TN 37831-6363.

8. Availability:   

Unrestricted
  
9. References:  
    
[1] C.E. Clifford, E.A. Straker, et al., "Measurements of the Spectra of Uncollided 
    Fission Neutrons Transmitted Through Thick Samples of Nitrogen, Oxygen, Carbon,
    and Lead:Investigation of the Minimum Total Cross Sections," Nucl. Sci. Eng. 
    27, 299 (1967).
[2] E.A. Straker, "Experimental Evaluation of Minima in the Total Neutron Cross 
    Sections of Several Shielding Materials," ORNL TM 2242, June 1968.
[3] R.E. Maerker, "SDT1. Iron Broomstick Experiment-An Experimental Check of Neutron
    Total Cross Sections," ORNL TM 3867, Sept., 1972.
[4] R.M. Freestone, Re-unfolding of original NE-213 Spectrometer results using FERD,
    est 1988, compiler acquired via private communication w/ D.T. Ingersoll, 5/96.
[5] R.E. Maerker and F.J. Muckenthaler, "The Absolute Neutron Spectrum emerging through 
    a 15-1/4-IN.Collimator from the TSR-II Reactor at the Tower Shielding Facility," 
    ORNL-TM-4010.

10. Data and Format:  
    
Tables:  
    (1) Neutron Source Spectrum (measured with sample removed)
    (2) Energy Resolution of NE-213 Spectrometer
    (3) 8-inch Fe Broomstick Measurements in E(MeV) and Flux (neuts/(cm2-MeV-min-W))
    (4) 12-inch Fe Broomstick Measurements in E(MeV) and Flux (neuts/(cm2-MeV-min-W))

Figures: 
    (1) Schematic of Experiment
    (2) Neutron Source Spectrum (measured with sample removed)


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SINBAD Abstract Generation Date: 06/98

SINBAD Abstract Last Update: 06/98