Analytical presentation of 235U and 252Cf fission neutron spectra

The analytical spectra representations in two forms - in form of the (2α3/2/√π)√E exp - αE model spectrum and the sum of the α2 E exp - αE nine model spectra, where αi = 4; 2; 1.333; 1.0; 0.8; 0.4; 0.2; 0.05; 0.01, are obtained on the basis of the representative sampling of the integral cross sections for the spectra of the 235U neutron fission through thermal neutrons and the 252Cf spontaneous fission. The conclusion is made on the achieved limit in the experimental determination of integral cross sections, on one side, and the accuracy of representation of energy dependences of the neutron interaction reactions, used by search of the spectral solution, in the other side