Measurement of Several 239Pu(n,xn) Partial (gamma)-Ray Cross Sections for x(<=)3 Using GEANIE at LANSCE/WNR.

Bernstein, L. A. ; Becker, J. A. ; Gatett, P. E. ; Hauschild, K. ; McGrath, C. A.

Technical Information Center Oak Ridge Tennessee

关键词: Cross sections;    Plutonium 239;    Gamma rays;    Time of flight spectrometers;    GEANIE(Germanium Array for Neutron Induced Excitations);   

RP-ID  :  DE200515013507

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The GEANIE spectrometer at LANSCE/WNR was used to measure a total of 13 partial y-ray cross section from the 239pU(n,xny)240-xpU channels with x= 1-3. The results reported here cover the incident neutron energy range from En=1-20 MeV. The partial cross sections were measured using the observation of discrete state y-rays using high-resolution y-rays spectroscopy. Neutron energies were determined using the time-of-flight technique. The majority (8) of the partial cross sections measured were from the 239Pu(n,2n)238pU reaction channel. Uncertainties in the partial cross sections come from Poisson counting statistics as well as systematic sources. Results from these measurements were compared the predictions the GNASH and IDA reaction models. Although the models and the shape of the measured values qualitatively agree, significant discrepancies exist which may in large part be attributable to the model treatment of the y-ray cascade process within the final residual nucleus and the role of K quantum number conservation in the nucleus.