Spin-echo small-angle neutron scattering study of the structure organization of the chromatin in biological cell

Spin-echo small-angle scattering (SESANS) technique is a method to measure the structure of materials from nano- to micrmeter length scales. This method could be important for studying the packaging of DNA in the eukaryotic cell. We measured the SESANS function from chicken erythrocyte nuclei which is well fitted by the exponential function G(z) = exp(-z/xi), where is the correlation length of a nucleus (in experimental data xi = 3, 3 m). The exponential decay of G(z) corresponds to the logarithmic pair correlation function gamma(r) = ln(xi/r). As the sensitivity of the SESANS signal depends on the neutron wavelength, we propose the SESANS setup with the changeable wavelength in the range from 2 to 12 angstrom. Such option allows one to study in great detail the internal structure of the biological cell in the length scale from 10(-2) mu m to 10 mu m.