A diffractometer is a

measuring instrument Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related ...

for analyzing the structure of a material from the

scattering In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiat ...

pattern produced when a beam of

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...

or particles (such as

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

s or

neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

s) interacts with it.

Principle

A typical diffractometer consists of a source of radiation, a

monochromator A monochromator is an optics, optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input. The name is . Uses A device that can ...

to choose the wavelength, slits to adjust the shape of the beam, a sample and a

detector A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

. In a more complicated apparatus, a

goniometer A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, γωνία (''gōnía'') 'angle' and μέτρον (''métron'') ' me ...

can also be used for fine adjustment of the sample and the detector positions. When an area detector is used to monitor the diffracted radiation, a beamstop is usually needed to stop the intense primary beam that has not been diffracted by the sample, otherwise the detector might be damaged. Usually the beamstop can be completely impenetrable to the X-rays or it may be semitransparent. The use of a semitransparent beamstop allows the possibility to determine how much the sample absorbs the radiation using the

intensity Intensity may refer to: In colloquial use * Strength (disambiguation) *Amplitude * Level (disambiguation) * Magnitude (disambiguation) In physical sciences Physics *Intensity (physics), power per unit area (W/m2) *Field strength of electric, m ...

observed through the beamstop. There are several types of X-ray diffractometer, depending on the research field (material sciences, powder diffraction, life sciences, structural biology, etc.) and the experimental environment, if it is a laboratory with its home X-ray source or a

Synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The strength of the magnetic field which bends the particle beam i ...

. In laboratory, diffractometers are usually an "all in one" equipment, including the diffractometer, the video microscope and the X-ray source. Plenty of companies manufacture "all in one" equipment for X-ray home laboratory, such as

Rigaku Rigaku Corporation is an international manufacturer and distributor of scientific, analytical and industrial instrumentation specializing in X-ray related technologies, including X-ray crystallography, X-ray diffraction (XRD), X-ray reflectivity, ...

Malvern Panalytical Malvern Panalytical is a Spectris plc company. The company is a manufacturer and supplier of laboratory analytical instruments. It has been influential in the development of the Malvern Correlator, and it remains notable for its work in the a ...

Thermo Fisher Scientific Thermo Fisher Scientific Inc. is an American life science and clinical research company. It is a global supplier of analytical instruments, clinical development solutions, specialty diagnostics, laboratory, pharmaceutical and biotechnology s ...

Bruker Bruker Corporation is an American manufacturer of scientific instruments for molecular and materials research, as well as for industrial and applied analysis. It is headquartered in Billerica, Massachusetts, and is the publicly traded parent comp ...

, and many others. There are fewer diffractometer manufacturers for

synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The strength of the magnetic field which bends the particle beam i ...

s, owing to few numbers of x-ray beamlines to equip and the need of solid expertise of the manufacturer. For material sciences, Huber diffractometers are widely known and, for structural biology, Arinax diffractometers are the reference. Nonetheless, due to few numbers of manufacturers, a large amount of

diffractometers are "homemade" diffractometers, realized by synchrotron engineering teams.

Uses

X-ray diffractometer instruments can be used for a variety of purposes including imaging crystal structures, phase determination, and identifying unfamiliar substances for use in crystallography, inspection, and pharmaceutical research for drug efficacy. A novel use of x-ray diffraction involves studying the surface of Mars to determine if it ever supported life.

References

{{Crystallography Measuring instruments

Principle

Uses

See also

References