In general terms SAED and XRD are the same, both differs on the wavelenght of the diffracted beam and are governed by the Bragg equation. As the wavelenght of the electrons (in SAED) is very small compared to the interplanar distances there is an approximation on the sine(theta), appox. to theta.

The fundamental difference is: in and XRD measurement (single or polycrystal) you observe the intensities and the position of the diffracted beam, but in SAED you only observe the position. This difference is just due to the conventional detectors. The positions of the diffracted beam gives you information about the crystalline system, and the intensity gives you information about the stoichiometry (and others like thermal vibration for example).

The SAED could show you a pattern of rings (from polycrystals) or a spots pattern (from simgle crystals). In powder XRD you observe rings integrated in every peak and in single crystals XRD you observe the same spots pattern than in SAED.

Hi, important of course, is also (to what Henry already wrote) that XRD is an integral method  while at SAED using the selected area aperture achieved a spatial resolution of 100 nm. The problem with the SAED is the exact vertical position of this aperture in the image plane of the objective lens in the beam path.

For higher spatial resolution CBED is suitable, for example, Tomorrow I upload some sheets of my lecture.

Like Henry and Volker wrote SAED offers a superior lateral resolution and possess much shorter wavelengths as compared to conventional XRD.

Due to the smaller wavelength the diffraction angles are for SAED only about a few degrees that result in a strongly reduced angular resolution. As a consequence the precision of determining the interplanar spacings (d_hkl) is much lower as for XRD (about 1-3%).

Additionally the higher spatial resolution of SAED means also, that the probed area is usually not larger than 2-5µm in diameter – SAED provides not really “representative” information.

On the other hand the structure factors for electron diffraction are up to 10,000 times higher than for x-ray diffraction providing substantially higher diffracted intensity. Thus, one can acquire a pronounced electron diffraction pattern much quicker than a x-ray diffraction pattern (within seconds).

Cheers Martin

Useful information. Thank you very much.

For easy and effective SAED calculations you can explore this link,

http://www.instanano.com/characterization/d-value-calculation/saed-d-value-calculation/

Thank you Dheeraj Kumar for useful link.

Dear Manohar,

SAED pattern is used to observe the crystalline nature of the sample For example, a) if your sample is amorphous you will get diffused rings,

b) if crystalline, bright spots,

c) if poly-nano-crystalline, small spots making up a rings, each spot arising from Bragg reflection from an individual crystallite.

Using these, find out the crystalline phase of your sample (each phase has a characteristic SAED pattern)

I am copying the further answer from Dr.Sajad from another forum, credits to him.

Here I explain the step-by-step method to index the SAED pattern

(i) measure the diameter, 2R, of each ring using some image processing software such as Image tool, for example. Lets say for the first ring, the 2R = 5.37 [1/nm]

(ii) obtain the value of radius, R, (w.r.t central spot); R= 2.68 [1/nm], the unit 1/nm means the distance is in reciprocal lattice

(iii) Obtain the interplanar distance (d), in real space, as 1/R; in our case d= 1/R = 1/2.68 =0.372 nm. note that the unit is nm now, as we are talking about real space.

Let us consider my sample is TiO2, I know (by comparsion with d-value of different phases in literature) that a d-value of 0.372 correspond to (101) plan of anatase TiO2.

(iv) Now you found the d value for 1 ring. Do the same for procedure to obtain d-values for other rings.

(v) compare the d-value (each of which correspond to a certain set of hkl indices) with the the diffraction data from literature (and you know what is the compositi

on of your sample), for example from http://rruff.geo.arizona.edu/AMS/amcsd.php

or ICSD data base.

In this way, you can index the SAED pattern and assign each ring an hkl value. In other words, you can find in which crystalline form your sample is.

Good Luck!