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In the formation of TEM diffraction patterns as shown in Figure 2683, the reciprocal lattice spacing R_hkl, measured as the distance from the origin (O, the location of the directly transmitted beam on the screen) to some diffraction spot (A), is related to the real crystal spacing d_hkl, by,

          d_hkl =λL/R_hkl -------------------------------- [2683]

where,
          L -- The camera length,
          λ-- The wavelength of the incident electron beam,
          λL -- The camera constant.

By determining the reciprocal space of a crystal, one is able to analyze:
          i) Texture of the material,
          ii) Grain orientation,
          iii) Burgers vector,
          iv) Line directions of dislocations,
          v) Crystallographic nature.