Abstract
A precise transmission measurement of the cross sections of Bismuth, Lead, Silicone and Carbon for 130 eV neutrons (Co-resonance) has been carried out. A new resonance method has been applied, using epithermal reactor neutrons, which have been scattered twice from Co-foils. - We obtained the total 130 eV cross sections: Bi: 9,182 ± 0,007 b, Pb: 11,295 ± 0,009 b, Si:2,0442 ± 0,0018 b, C: 4,746 ± 0,007 b. From these results the coherent nuclear scattering lengths (bound), Bi: 8,646 ± 0,005 fm, Pb : 9,524 ± 0,004 fm, C: 6,660 ± 0,006 fm, have been calculated, under consideration of various corrections (absorption, Schwinger-scattering, Incoherence, Neutron-Electron-Interaction, energy-dependence of nuclear-scattering).