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NEUTRON THERMALIZATION MEASUREMENTS USING AN ELECTRON LINEAR ACCELERATOR

Description: Discussions are presented concerning integral experiments primarily on water and graphite systems. A description of experimental facilities is included along with details of die-away experiments, infinite-medium spectrum measurements, spatially dependent spectrum measurements, spectrum measurements for graphite systems, and development of a subcritical assembly program. (J.R.D.)
Date: April 10, 1962
Creator: Beyster, J R
Partner: UNT Libraries Government Documents Department

INTEGRAL NEUTRON THERMALIZATION. Annual Summary Report, October 1, 1961- September 30, 1962

Description: 3 3 9 9 7 6 : < 6 9 9 4 9 7 pulse of within a factor of two of the highest now available; operation was more than satisfactory. A pressure vessel to be used with the linac to measure neutron spectra of poisoned solutions for moderator temperatures up to about 600 l F was constructed. A 150-kv positive-ion accelerator was added to the linac facility to produce 2.5 and 14-Mev neutrons from T(d,n) and d(d,n) reactions. The 14-Mev neutron yield is about 10/sup 11/ neutrons/sec. Facilities for measuring neutron spectra were rearranged to eliminate systematic errors; reorientation of the 16-m detector bank necessitated remeasurement of the sensitivity of the bank as a function of neutron energy. Sensitivity of the 50-m bank was also remeasured. The effects on spectra of the scatterer, the location of pulsed neutron sources, the precollimator location and opening, and the linac intensity were also evaluated. To obtain information on the reliability of flux values predicted by standard transport theory approaches, angular dependent and scalar spectra were measured in 4- and 2-in. slab geometry and were compared with theoretical spectra. One-dimensional slab measurements were analyzed with the DSN and THERMOS codes. Results show that an anisotropic component of the scattering kernel is by far the most important refinement to the isotropic calculation. A multiplying assembly, nearly free of the large spatial effects induced by the external source, was constructed; and spectra were measured under distributed source conditions and compared with one-dimensional transport theory calculations. Neutron die-away was also studied. The feasibility of making spectral measurements by time-of-flight techniques in a system with a relatively long neutron die-away time was considered. Fluxes and spectra were obtained and compared with DSN calculations. Influence of various types of absorption, 1/v or resonance, on infinite-medium neutron spectra for ...
Date: October 31, 1963
Creator: Beyster, J. R.; Brown, J. R. & Honeck, H. C. et al.
Partner: UNT Libraries Government Documents Department

INTEGRAL NEUTRON THERMALIZATION. Quarterly Progress Report for the Period Ending June 30, 1963

Description: Decay constant and modal analysis measurements were performed in a U/sup 235/-water critical assembly, and infinitemedium neutron spectra in water poisoned with a 1/V absorber were measured at various pressures and temperatures. The results were compared with theoretical predictions. Neutron penetration of water shielding was also measured. Theoretical work involved models and codes for neutron thermalization in ZrH, Be, and water. (D.C.W.)
Date: July 26, 1963
Creator: Young, J. C.; Beyster, J. R.; Brown, J. R.; Houston, D. H.; Kirkbride, J.; Koppel, J. U. et al.
Partner: UNT Libraries Government Documents Department