X-ray Technology

XRD Basics

X-ray diffraction (XRD) is among the most effective tools for non-destructively acquiring detailed phase and structural information from material samples. By measuring the diffraction angle of a primary X-ray beam according to Bragg’s Law (λ = 2d sinθ, with λ: wavelength, d: d spacing, θ: diffraction angle), it is possible to characterise and identify various chemicals, phases, and structures within samples. This is ideal for research and industrial applications concerned with the structural characterisation of polycrystalline materials.

Stand-alone XRD solutions are routinely used in sectors as varied as applied materials, pharmaceuticals, semiconductors, and more. For routine quality assurance and control of raw materials (cement, metals, etc.), integrated X-ray fluorescence XRD (XRF-XRD) instrumentation are often preferable.

If you would like to learn more about using XRD, or XRF-XRD, instruments for your application, speak with a member of our team.

Contact us

What is XRD?

X-ray diffraction (XRD) is a foundational technology in solid-state science, providing unique insights into the chemical composition and structural arrangement of samples of interest. The relevant data are obtained by measuring the intensity of a primary X-ray beam generated by a cathode ray tube against the diffraction angle, as per Bragg’s Law. Consequently, many different transmission-reflection geometries can be arranged to analyse specific samples. This necessitates an array of intuitive moving parts.

Diffraction is an optical process whereby a beam of light spreads out after crossing an edge or passing through an aperture. This occurs at the atomic level, as electrons orbiting the nucleus of an atom will coherently scatter light according to the number of electrons present. The atoms in crystalline and polycrystalline materials are arranged periodically, which means they can constructively interfere with light of suitably short-wavelengths to produce a diffraction pattern. X-rays are short enough to be scattered in this manner.

In an XRD test, a sample is placed within a chamber and is bombarded with a beam of primary X-rays at an angle defined by the relevant diffraction geometry (i.e. Theta-Theta Bragg-Brentano). The Bragg-Brentano geometry among the most common methods used in powder XRD, otherwise known as XRPD. It relies on multiple moving parts to detect the secondary scattered X-rays from a sample and obtain a full diffraction pattern. Provided Bragg’s Law has been satisfied, when the primary X-ray beam interacts with the sample it will diffract and produce a secondary beam that can be acquired by a detector. This yields a diffraction pattern that is characteristic of the unique crystallographic structure of the sample. Diffractometers with real-time position sensitive detectors can offer even more dynamic insights, such as phase changes over time due to thermodynamic variations.

XRD patterns allow analysts to perform a variety of structural investigations, such as fingerprinting of phase content, which requires a comparison of the relative intensities and positions of reflections against existing data in available databases. This is one of the most widely-accepted methods of screening for phase control in an array of industrial processes.

Understanding the structure of your materials can help you adapt to new challenges unique to your market sector. We offer the products, services and technologies to help you understand your materials, regardless of the application. See our listing of resources for XRD in these areas:

XRD Product Guide

Powder XRD offers state-of-the-art insights into the phase content of myriad different sample types, laying the foundation for excellence in manufacturing quality control and routine academic studies. Satisfying this diverse range of applications requires an outstanding level of versatility. Thermo Fisher Scientific sets the benchmark for quality and flexibility in powder XRD instrumentation, using a choice of diffraction geometries, optics and research accessories for true precision across a wide cross-section of application areas.

Thermo Fisher Scientific powder X-ray diffractometers are delivered under the trusted ARL EQUINOX product line, featuring both compact benchtop and full-scale XRD solutions.



Get a dedicated XRD instrument designed for QA/QC, academic, and routine X-ray diffraction applications with the compact, affordable Thermo Scientific ARL EQUINOX 100 X-ray Diffractometer. Occupying a third of the space of a conventional diffractometer, this standalone, transportable bench top instrument offers true flexibility; no external water cooling is required, and it plugs into a standard electrical power outlet.



Experience real-time measurement in a simple yet powerful benchtop XRD analyzer with the Thermo Scientific ARL EQUINOX 1000 X-ray Diffractometer. Designed for QA applications and routine X-ray diffraction studies, this high power XRD instrument offers maintenance free, simplified operation while providing high resolution performance.



Experience fast, accurate measurements with the Thermo Scientific ARL EQUINOX 3000 X-ray Diffractometer. This research-grade diffraction system provides higher resolution detectors, a larger sample area, and choice of X-ray sources. The large sample compartment accommodates practically any sample and any sample handling device, including furnaces, auto samplers, large assemblies, etc.

Featured XRD videos

ARL EQUINOX 100:­ Compact, affordable and transportable benchtop XRD system for QA/QC, academic, and routine applications

ARL EQUINOX 3000:­ Research-grade diffraction system for fast and accurate measurements with high resolution detectors, large sample area and choice of X-ray sources


Download the XRD Quick Guide Poster
Powder XRD Quick Guide Poster

In X-ray diffraction (XRD) the intensity of X-rays diffracted by the sample are measured according to the diffraction angle.

Stand-alone XRD instruments are widely used in both research and industry dealing with structural characterization of materials.

Our X-ray Diffraction Quick Guide poster summarizes the XRD basic theory, technology and main applications. Download it now for free!


Download poster