X-ray diffraction

Principle

The sample is mounted on a goniometer and gradually rotates while being bombarded with X-rays, producing a diffraction pattern of regularly spaced spots known as diffractions.

The diffracted beams add constructively in a few specific directions, determined by Bragg’s law:

- n. = 2.d.sin ø

Here d is the spacing between diffracting planes, θ is the incident angle, n is any integer, and λ is the wavelength of the beam. These specific directions appear as spots on the diffraction pattern.

Principle of X-rays diffraction

The goniometric counter measures diffracted X-Rays intensity as a function of the diffraction angle. Plotting the angular positions and intensities of the resultant diffracted peaks of radiation produces a pattern, which is characteristic of the sample. Where a mixture of different phases is present, the resultant diffractogram is formed by addition of the individual patterns.

Characteristics :

 Powdered or massive,
 X-rays source : 30kV, 15 mA , copper anticathode

Goniometer :
- lenght : 150 mm,
- angle range from -3° to 150° (2theta),
- scan speed : from 0,01° to 100°/min (2theta)