Röntgenkleinstwinkelstreuung an Erythrocyten

The operational range of X-ray small-angle scattering was extended to particles and structures in the μm-range by the construction of a 50 m long scattering device. Erythrocytes were selected as a suitable object for study. They were found to have a radius of gyration of 2.3 ± 0.2 μm, corresponding to a particle diameter of 6.0 ± 0.5 μm. The volume was calculated from Perod's invariant and found to be 67 ± 10 μm³. For the first time, absolute measurements could be done without weakening the primary beam, which allowed the direct determination of the mass of the particle. The mass of the erythrocyte was calculated to be 78 ± 20 pg. In all experiments a slit collimation was used. The divergence of the incident beam was smaller than the halfwidth of the scattering curve by a factor of 2.5. Therefore, the low-angle region of the scattering profile was hardly influenced by distortions due to collimation disregarding the normalization factor.