Accuracy evaluation of nuclear reactor gamma spectra reconstruction by the directed divergence method

An algorithm of accuracy evaluation of nuclear reactor gamma spectra reconstruction according to the data on integral detectors using the directed divergence method (DDM) is considered. The minimally available value of the distinguishing functional taken in DDM is evaluated by the statistical linearization method. The spectra reconstruction accuracy is studied by the statistical simulation method using the numerical experiment. It is shown that the increase of the number of detectors in the set does not improve the approximation of the real spectrum, but it can increase the reconstruction accuracy while using noncorrelated detectors. The increase of the measurement accuracy considerably improves the solution and reduces its dispersion. To keep high confidence of the results it is necessary to increase the number of detectors, but under the conditions of strong correlation bonds, the requirement of high measurement accuracy does not reduce the solution dispersion. On the basis of the analysis of the results of statistical simulation according to the spectra of different forms the conclusion is made that the spectra reconstruction error while varying only the detector readings depend on the initial data accuracy. The error >3-5% included into the sensitivity matrix elements often leads to such a sharp reconstruction error increase that the problem loses it sense. During joint varying the dispersion of the matrix elements and detector readings are summed up as it was expected. It is emphasized that utilization of the statistical simulation helps to have a complete answer to the question on accuracy and resolution of measurements of the nuclear reactor gamma radiation spectra using the integral detectors