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2.12 PEACO ; The hyperfine Group Resonance Absorption Calculation
The input of this section is required when PEACO routine is used for effective microscopic
resonance cross-sections by specifying IC5=2 or -2 (Sect.2.2).
Block-1 /1/
IPLOT Plot control for spectra by PEACO in resonance energy range
Plot data is stored as a PostScript file (cf. Sect.1.11).
= 0 Skip plot
= ±1 Plot neutron spectra by up-to five R-Regions in one figure
= ±2 Plot neutron spectra by R-Region for an R-Region per figure
= ±3 Plot neutron spectra by up-to five R-Regions in one figure in the energy
ranges which are specified in Block-3 and -4.
Note:
If negative value is entered, group cross-sections modified by PEACO
calculation are printed out in the users fine-group structure.
Block-2 Required if IC5=-2 /NMAT/
(IRX(i),i=1,NMAT)
PEACO routine has a restriction so that one or two independent resonant
material(s) can be treated, where an resonant material is defined as a material to
contain at least one nuclide of which cross-sections are stored in MCROSS file.
When more than two resonant materials exist in the system, they must be classified
into one of two groups by their characteristics. This item specifies the material
group in the order appearing in the material specifications (Sect.2.9)
= 0 Non-resonant region
= 1 Assign to the first resonant material
= 2 Assign to the second resonant material
Note:
PEACO routine calculates the collision probabilities by interpolation of
tabulated probabilities by using the total cross-section as argument. Such tabulation
can be prepared for the combination of two different total cross-sections. This is
the reason of the restriction. If the third resonance material has almost same energy
structure with any of two materials, an approximation to assume the third is
equivalent to any of the two holds. Most of resonance absorption is, as known,
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