Estimating Reaction Cross Sections from Measured (Gamma)-Ray Yields: The 238U(n,2n) and 239Pu(n,2n) Cross Sections

Younes, W

Lawrence Livermore National Laboratory

关键词: Algebra;    Cross Sections;    Algorithms;    71 Classical And Quantum Mechanics, General Physics;    Energy Levels;   

DOI  :  10.2172/15002344
RP-ID  :  UCRL-ID-151070
RP-ID  :  W-7405-ENG-48
RP-ID  :  15002344

美国|英语

来源: UNT Digital Library

【 摘 要 】

A procedure is presented to deduce the reaction-channel cross section from measured partial {gamma}-ray cross sections. In its simplest form, the procedure consists in adding complementary measured and calculated contributions to produce the channel cross section. A matrix formalism is introduced to provide a rigorous framework for this approach. The formalism is illustrated using a fictitious product nucleus with a simple level scheme, and a general algorithm is presented to process any level scheme. In order to circumvent the cumbersome algebra that can arise in the matrix formalism, a more intuitive graphical procedure is introduced to obtain the same reaction cross-section estimate. The features and limitations of the method are discussed, and the technique is applied to extract the {sup 235}U (n,2n) and {sup 239}Pu(n,2n) cross sections from experimental partial {gamma}-ray cross sections, coupled with (enhanced) Hauser-Feshbach calculations.