ИСТИНА

Cross sections of partial photoneutron reactions (g,1n), (g,2n), and (g,3n), as well as of total reaction σ(g,sn) = σ(g,1n)+σ(g,2n)+σ(g,3n) and of photoneutron yield σ(g,xn) = σ(g,1n)+2σ(g,2n)+3σ(g,3n) collected in the international nuclear reaction database are widely used in nuclear physics basic research to study various features of electromagnetic interactions and resulted in founding collective states in atomic nuclei, obtaining various giant resonances, first of all Giant Dipole Resonance (GDR). Various characteristics of those, such as resonance energy position, absolute value, integrated cross sections and moments, parameters of GDR configurational and isospin splitting, and others, were determined. Total accuracy of those quantities is arbitrarily low because the results of different photonuclear experiments are significantly different in absolute value. Disagreements about 100 percents (or larger) are known in many cases, those are definitely systematic for partial reactions. Using digital cross-section data from database and experimental-theoretical method for evaluation partial reaction cross sections meeting objective physical criteria it was shown that for about 70 nuclei from 51V to 209Bi many experimental cross sections under discussion are not reliable because they contain significant systematic uncertainties of various types due to discrepancies in methods of neutron multiplicity identification and characteristics of g-quanta sources, neutron detectors and devices for g-quanta beam monitoring. New reliable cross sections of total and partial reactions were evaluated and analyzed.