ARCFIT-1, -2 and -3: Codes for revision of group constants for heavy nuclei of JAERI-fast set

The codes ARCFIT-1, -2 and -3 have been developed for adjustment of group constants for heavy nuclei of JAERI-Fast Set. In the measurements of differential cross sections, it is well-known that relative measurement of cross section has better accuracy than absolute measurement. On the basis of this fact, conserving the ratio of the differential cross section the code ARCFIT-1 performs the adjustment of group cross sections by the least squares fit of the effective multiplication factors. The code ARCFIT-2 searches for the average resonance parameters by fitting of the adjusted group cross sections in the unresolved resonance region. This code is especially powerful for evaluation of the average resonance parameters. The code ARCFIT-3 can generate the resonance levels and parameters using random sampling method, and searches for a ladder of resonance parameters which reproduces the adjusted group cross sections. User guides for these codes are described together with some examples. (auth.)