Systematic study on spectral effects in the adjustment calculations using the NEUPAC-83 code

The improvements of the neutron unfolding package code NEUPAC-83 were made sucessfully on several points such as an introduction of non-negative estimation algorithm (J-log method) and a preparation of the dosimetry cross section with covariance library. In addition to these improvements, systematic study has been made by the NEUPAC-83, focussing our attention on the spectral covariance effects in the adjustment calculations. The results may be summarized as follows: (1) adjusted integral values are influenced considerably by the prior probability density function of initial neutron spectrum, especially by the correlation factor, and (2) the determination method of statistically permitted area of the solutions should be applied more effectively in the adjustment calculation. (Auth.)