SINBAD ABSTRACT NEA-1517/21
SBE 1.011

1. Name of Experiment:  

SDT4. Sodium 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
sodium in the range of 0.8 - 11.0 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-in. collimator made of water and lithiated paraffin. The 24-inch-
thick sample of sodium was placed approximately 50 feet away from the source, 
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 sodium sample. The detector was 
placed approximately 50 feet behind the sample and was shielded with water and lead.
The purpose for the distance between source, sample and detector was 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, (sodium sample removed and lead, stainless 
steel container housing the sample left in place) to collect a source spectrum, for 
use in the calculated uncollided spectrum. Data was then collected for a 60.56-cm-
wide x 40-inch-diameter sodium sample. The density of the sample was 0.0254 
atoms/barn-cm and considered to be 100% Na.

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 3870 (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, "SDT4. Sodium Broomstick Experiment-An Experimental Check of 
    Neutron Total Cross Sections," ORNL TM 3870, 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 SS container and lead in place, w/o 
        sodium)
    (2) 24-inch Sodium Broomstick Measurements in Energy (MeV) and Flux
        (neuts/(cm2-MeV-min-W))
	
Figures: 
    (1) Schematic of Experiment
    (2) Neutron Source Spectrum (measured with SS container and lead in place, w/o 
        sodium)


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SINBAD Abstract Generation Date: 06/98

SINBAD Abstract Last Update: 06/98