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SBE 1.010

1. Name of Experiment: 

SDT3. Nitrogen 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
nitrogen in the range of 0.8 - 10 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 36-inch
sample of nitrogen 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 nitrogen 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, (nitrogen 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 36-inch-long x 4-inch-diameter nitrogen 
sample. The density of the sample was 0.0347 atoms/barn-cm and considered to be 
100% N2. 
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

    R.E. Maerker ORNL TM 3869 (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, "SDT3. Nitrogen Broomstick Experiment-An Experimental Check of 
    Neutron Total Cross Sections," ORNL TM 3869, 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," 
10. Data and Format:  
    (1) Neutron Source Spectrum (measured with dewar empty)
    (2) 36-inch Nitrogen Broomstick Measurements in Energy (MeV) and Flux
    (3) Alternate 36-inch Nitrogen Broomstick Measurements in Energy (MeV) and Flux
    (1) Schematic of Experiment
    (2) Neutron Source Spectrum (measured with dewar empty)

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SINBAD Abstract Generation Date: 06/98

SINBAD Abstract Last Update: 06/98