Guinier plot 

https://doi.org/10.1351/goldbook.G02712
A diagrammatic representation of data on scattering from large particles, obtained at different angles but at the same concentration, constructed by plotting log10ΔR(θ) or log10P(θ) versus (sinθ2)2 or q2 and (usually) used for the evaluation of the radius of gyration. ΔR(θ) is the excess Rayleigh ratio, P(θ) the particle scattering function, θ the scattering angle and q the length of the scattering vector.
Source:
Purple Book, 1st ed., p. 67 [Terms] [Book]