= Solution
Indexed <electron diffraction> ring positions from a polycrystalline deposit identify candidate phases and give <lattice parameters> after camera-length calibration. Spot patterns from a small selected area establish <zone axis> directions, epitaxial orientation relationships or <crystal twinning>. Nanobeam mapping can reveal grain orientation changes, while systematic spot shifts can measure relative <strain> if lens distortions and scan drift are controlled. Spot or ring broadening can reflect finite coherent size, but also <strain> and instrumental broadening, so it is not an unqualified particle-diameter measurement. Use a calibration standard and an empty support region, vary dose to check <electron beam damage>, and combine spacing information with elemental analysis when chemically distinct phases have similar <lattice parameters>.
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