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U.S. Department of Energy
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SIOB: a FORTRAN code for least-squares shape fitting several neutron transmission measurements using the Breit--Wigner multilevel formula. [For IBM-360/91]

Technical Report ·
DOI:https://doi.org/10.2172/6877401· OSTI ID:6877401
The FORTRAN-IV code SIOB was developed to least-square fit the shape of neutron transmission curves. Any number of measurements on a common energy scale for different sample thicknesses can be simultaneously fitted. The computed transmission curves can be broadened with either a Gaussian or a rectangular resolution function or both, with the resolution width a function of energy. The total cross section is expressed as a sum of single-level or multilevel Breit--Wigner terms and Doppler broadened by using the fast interpolation routine QUICKW. The number of data points, resonance levels, and variables which can be handled simultaneously is only limited by the overall dimensions of two arrays in the program and by the stability of the matrix inversion. In a test problem seven transmissions each with 3750 data points were simultaneously fitted with 74 resonances and 110 variable parameters. The problem took 47 min of CPU time on an IBM-360/91, for 3 iterations. 3 figures, 2 tables.
Research Organization:
Oak Ridge National Lab., Tenn. (USA)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
6877401
Report Number(s):
ORNL/TM-6286; ENDF-261
Country of Publication:
United States
Language:
English