Table 2. Summary of all the most relevant cases that can be encountered during the study of the signature of single defects.

For each case the maximum intensity calculated on the CXD pattern is compared with the intensity for a defect-free crystal with the same size and shape. In the following n is the direction normal to a stacking fault, t is the dislocation line direction, and b t is the direction perpendicular to both the Burgers vector and the dislocation line direction. The best conditions to show the defect are highlighted in italic, while the invisibility conditions are highlighted in bold. N/A: not applicable; SF: stacking fault.

	Screw dislocation		Edge dislocation
	Unrelaxed	Relaxed	Unrelaxed	Relaxed	Stacking fault	Frank dislocation loop	Prismatic dislocation loop
g(b t) = 0	Single clean spot	Single clean spot	Single clean spot	Single clean spot, fringes along n	N/A	Small drop of intensity in Bragg position	Single clean spot, slight distortion in the pattern
	I = I 0	I = I 0	I = I 0	I = 0.78I 0		I = 0.85I 0	I = I 0
g b = 0, g(b t ) 0	Single clean spot	Splitting along b, fringes along n	Elongation along b	Splitting along b, fringes along n	N/A	Single clean spot, slight disturbances	Single clean spot, drop of intensity in Bragg position
	I = I 0	I = 0.2I 0	I = 0.4I 0	I = 0.2I 0		I = 0.8I 0	I = 0.65I 0
g||b	Ring-shaped pattern: ring axis along b; extinction in Bragg position	Ring-shaped pattern: ring axis along b; extinction in Bragg position; maxima of intensity along [001]	Fringes along n, elongation of Bragg peak along b	Fringes along n, elongation of Bragg peak along b and increased intensity in Bragg position	N/A	Satellite spot and low intensity in Bragg position	Hexagonal-shaped pattern with elongation along b, fringes along n, intensity maximal in Bragg position
	I = 0.14I 0	I = 0.18I 0	I = 0.18I 0	I = 0.33I 0		I = 0.3I 0	I = 0.5I 0
						No fringes along n: g with h + k + l = 3n
g||b p	Ring-shaped pattern: ring axis along b; extinction in Bragg position	Ring-shaped pattern: ring axis along bp; extinction in Bragg position	Fringes along n, elongation of fringes along b, extinction in Bragg position	Fringes and splitting along n, elongation of fringes along b	N/A	Distorted ring-shaped pattern for g||bSR with ring axis along bSR	Similar to g||b with a lower intensity in Bragg position
	I = 0.09I 0	I = 0.11I 0	I = 0.09I 0	I = 0.23I 0		I = 0.16I 0	I = 0.35I 0
g with h + k + l = 3n	N/A (no SF)	Fringes along n disappear	N/A (no SF)	Fringes along n disappear	Single clean spot	Fringes along n disappear	Fringes along n disappear
					I = I 0
g with h + k + l 3n	N/A	Fringes along n	N/A	Fringes along n	Intense fringes along n and splitting due to the 2/3 phase jump induced by the SF; intensity in Bragg position 25% that of perfect crystal	N/A	N/A
General g	Ring-shaped pattern; ring diameter inversely proportional to crystal size and hkl indices	Ring-shaped pattern; distortion and disorientation of the ring depending on the hkl indices of the diffraction vector; increase of the maxima of intensity during relaxation	Fringes and splitting along n and elongation of Bragg peak and/or of fringes along b, depending on the selected diffraction vector	Fringes and splitting along n and elongation/ splitting along b depending on the selected diffraction vector; increase of the maximum intensity during relaxation	Only two possible cases (see above)	Three main effects: (1) fringes along n normal to the SF, (2) ring-shaped pattern along one of the stair-rod partials, and (3) decrease of the intensity of the central spot and appearance of a satellite spot depending on hkl	Distorted hexagonal-shaped pattern not oriented along a particular direction and dependent on the hkl indices of g; maximum intensity lower than that of perfect crystal