A method for creating a theoretical signature of a crystalline material sample, the theoretical signature corresponding to a curve of theoretical backscattered intensities as a function of acquisition geometries, characterised in that the method comprises the following steps: - modelling a three-dimensional atomic structure of the sample, the structure comprising at least one crystal lattice, said modelling step comprising a sub-step consisting of selecting atoms of at least one crystal lattice and contained in a selection volume, the selection volume having a symmetry of rotation such that the distance between a centre of the structure and the atoms arranged at the periphery of the structure is substantially constant; - then, for each acquisition geometry: ∘ positioning the structure according to the desired acquisition geometry by moving the spherical structure relative to the projection plane; ∘ defining a level of interaction for each atom, said step consisting of allocating, to each atom, a coefficient representative of a theoretical contribution of the atom to the backscattered intensity, said coefficient consisting of a greyscale value attributed to each atom of the structure according as a function of: ▪ the distance between said given atom and the projection plane, and/or ▪ the number of atoms located between said given atom and the projection plane, ∘ calculating the projection of the atoms of the structure in the projection plane in order to obtain a projection image; ∘ estimating the backscattered intensity on the basis of the projection image; and - generating the theoretical signature on the basis of a plurality of estimated theoretical backscattered intensities. - modelling a three-dimensional atomic structure of the sample, the structure comprising at least one crystal lattice, said modelling step comprising a sub-step consisting of selecting atoms of at least one crystal lattice and contained in a selection volume, the selection volume having a symmetry of rotation such that the distance between a centre of the structure and the atoms arranged at the periphery of the structure is substantially constant; - then, for each acquisition geometry: ∘ positioning the structure according to the desired acquisition geometry by moving the spherical structure relative to the projection plane; ∘ defining a level of interaction for each atom, said step consisting of allocating, to each atom, a coefficient representative of a theoretical contribution of the atom to the backscattered intensity, said coefficient consisting of a greyscale value attributed to each atom of the structure according as a function of: ▪ the distance between said given atom and the projection plane, and/or ▪ the number of atoms located between said given atom and the projection plane, ∘ calculating the projection of the atoms of the structure in the projection plane in order to obtain a projection image; ∘ estimating the backscattered intensity on the basis of the projection image; and ∘ positioning the structure according to the desired acquisition geometry by moving the spherical structure relative to the projection plane; ∘ defining a level of interaction for each atom, said step consisting of allocating, to each atom, a coefficient representative of a theoretical contribution of the atom to the backscattered intensity, said coefficient consisting of a greyscale value attributed to each atom of the structure according as a function of: ▪ the distance between said given atom and the projection plane, and/or ▪ the number of atoms located between said given atom and the projection plane, ▪ the distance between said given atom and the projection plane, and/or ▪ the number of atoms located between said given atom and the projection plane, ∘ calculating the projection of the atoms of the structure in the projection plane in order to obtain a projection image; ∘ estimating the backscattered intensity on the basis of the projection image; and - generating the theoretical signature on the basis of a plurality of estimated theoretical backscattered intensities.