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SBE 1.009

1. Name of Experiment:  
SDT2. Oxygen 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
oxygen in the range of 1.9 - 8.6 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 60-inch
sample of oxygen 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 oxygen 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 and 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, (oxygen sample removed, dewars and lead left
in place) to collect a source spectrum, for use in the calculated uncollided 
spectrum. Data was then collected for a 60-inch-wide x 4-inch-diameter oxygen 
sample. The density of the sample was 0.0429 atoms/barn-cm and considered to be 
100% O2. 
6. Special Features:


7. Author/Organizer:  

    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 3868 (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 
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:  
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, "SDT2. Oxygen Broomstick Experiment-An Experimental Check of 
    Neutron Total Cross Sections," ORNL TM 3868 (Sept., 1972) and addenda.
[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," 

10. Data and Format:  

    (1) Neutron Source Spectrum (measured with dewars empty)
    (2) 60-in. Oxygen Broomstick Measurements in Energy (MeV) and Flux 
    (1) Schematic of Experiment
    (2) Neutron Source Spectrum (measured with dewars empty)
    (3) Transmitted Neutron Spectrum Through Oxygen

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SINBAD Abstract Generation Date: 06/98

SINBAD Abstract Last Update: 06/98