ANALYSIS OF THE RECENT TSF SECONDARY GAMMA-RAY EXPERIMENT

Technical Report · Tue Sep 23 04:00:00 EDT 1958

DOI:https://doi.org/10.2172/4308215· OSTI ID:4308215

Keller, F. L.; Merrill, O. S.

Since the existing experimental data on gamma rays produced by the inelastic scattering of neutrons with oxygen and nitrogen are rather sparce, it is necessary to rely upon theoretical cross sections to predict the spectra of inelastic scattering gamma rays produced by an ordinary neutron flux distribution. Because of the model used in the cross section calculation a considerable amount of uncertainty existed in regard to the accuracy of these results. In order to provide a check on the results of such calculations, an experiment was performed at the ORNL Tower Shielding Facility to directly measure the spectra of capture and inelastic scattering gamma rays produced in air by a reactor neutron spectrum. Unfortunntely, it was necessary to make these gamma-ray measurements behind a thick shield through which a long water collimator was inserted. Hence, before a direct comparison could be made between the calculations and the experiment it was necessary to first calculate the spectra of capture and inelastic scattering gamma rays produced in air, then to determine the effect of attenuation and buildup in the water collimator, and finally, to include the detector response functions. When the calculated and measured pulse-height distributions were compared the shapes were found to be in excellent agreement. This indicates that considerably more confidence may be placed in calculations which use spectra of inelastic scattering gamma rays determined from the existing theoretical cross section. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-12-016781
• OSTI ID: 4308215
• Report Number(s): ORNL-2586
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION-- AIR-- CAPTURE-- CROSS SECTIONS-- ERRORS-- GAMMA RADIATION-- MEASURED VALUES-- NEUTRON FLUX-- NEUTRONS-- NITROGEN-- NUCLEAR MODELS-- OXYGEN-- PULSE ANALYZERS-- REACTORS-- SCATTERING-- SENSITIVITY-- SHIELDING-- SPECTRA-- WATER
GAMMA SPECTROMETERS
PHYSICS