Xr Diffraction

  1. X Ray Diffraction Principle
  2. Xr Diffraction Definition
Xr Diffraction
  • X-ray diffraction, or XRD, is a technique for analysing the atomic or molecular structure of materials. It is non-destructive, and works most effectively with materials that are wholly, or part, crystalline.
  • The LISST-200X is a submersible laser-diffraction based particle size analyzer designed to measure particle size and concentration in rivers, streams, ports, harbors, coasts and oceans, whether for biological, sediment transport, or environmental monitoring needs.

The LISST-200X is a submersible laser-diffraction based particle size analyzer designed to measure particle size and concentration in rivers, streams, ports, harbors, coasts and oceans, whether for biological, sediment transport, or environmental monitoring needs.

Sediment sensor holding calibration FOR LIFE!

Our workhorse LISST-200X marks a major advance in technology over our discontinued LISST-100X submersible laser-diffraction instrument. The LISST-200X is used in rivers, streams, ports, harbors, coasts and oceans. It also measures the small-angle optical volume scattering function (VSF).

X ray diffraction

The LISST-200X holds calibration for life.

  • Measures Particle Size and Concentration
  • Particle Size Range: 1.0 to 500 microns
  • Small angle VSF: 0.039 to 13.8 degrees.
  • Extended Depth Rating: 600 meters
  • Automated Pass/Fail report on Backgrounds
  • Half the physical size of the discontinued LISST-100X
  • Smarter data file structure
  • Analog output of size and concentration
  • Plug and Play Compatible with most CTDs

When an X-ray is shined on a crystal, it diffracts in a pattern characteristic of the structure. In powder X-ray diffraction, the diffraction pattern is obtained from a powder of the material, rather than an individual crystal. Powder diffraction is often easier and more convenient than single crystal diffraction since it does not require individual crystals be made. Powder X-ray diffraction (XRD) also obtains a diffraction pattern for the bulk material of a crystalline solid, rather than of a single crystal, which doesn't necessarily represent the overall material. A diffraction pattern plots intensity against the angle of the detector, (2theta).

Introduction

Since most materials have unique diffraction patterns, compounds can be identified by using a database of diffraction patterns. The purity of a sample can also be determined from its diffraction pattern, as well as the composition of any impurities present. A diffraction pattern can also be used to determine and refine the lattice parameters of a crystal structure. A theoretical structure can also be refined using a method known as Rietveld refinement. The particle size of the powder can also be determined by using the Scherrer formula, which relates the particle size to the peak width. The Scherrer fomula is

[t = dfrac{0.9 lambda}{sqrt{B^2_M-B^2_s} cos theta}]

with

X Ray Diffraction Principle

  • (lambda) is the x-ray wavelength,
  • (B_M) is the observed peak width,
  • (B_S) is the peak width of a crystalline standard, and
  • (theta) is the angle of diffraction.

Xr Diffraction Definition

To the left is an example XRD pattern for (Ba_{24}Ge_{100}). The x axis is (2theta) and the y axis is the intensity.