Unresolved resonance region

Resonances present in the nuclear data library are fully tabulated in the total cross section. In the unresolved resonance region, MONK merely takes the unresolved cross-sectional data without any further additions. 

S. C. COHEN and P. K. KOCH, "GANDY, A Computer Program for the Evaluation of Effective Cross Sections in the Unresolved Resonance Region, GA-8003, General Atomic (1967). 

To make applicable for criticality calculation, how far into the unresolved resonance region must one superimpose fine structure on the observed mean reaction cross sections. 

The H-NMR spectrum of 2 in CDCI3 (Figure 1) exhibits broad unresolved resonances in the aromatic region similar to those found in the monomer. Broad signals with lack of resolution are consistent with magnetic non-equivalence of the methyl group protons resulting from a mixture of triad tacticities. 

In practical usage the constants a and C are empirically-determined. Only experiments at low E, like resonance counting, are sensitive to the prefactor C. Experiments in the region of unresolved states are sensitive only to a relative change in the level density, i.e., (o E + A)/ co E ), and thus only the level density parameter a can be extracted. It is the parameter a that... 

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