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. In a more complicated apparatus, a
goniometer 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 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.
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,
Malvern Panalytical,
Thermo Fisher Scientific,
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
synchrotrons, 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
synchrotron 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.
See also
*
Crystallography
Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word ''crystallography'' is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In J ...
*
International Centre for Diffraction Data
*
Neutron diffraction
Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of Neutron temperature, thermal or ...
*
Spallation Neutron Source
*
X-ray crystallography
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...
*
X-ray diffraction
X-ray diffraction is a generic term for phenomena associated with changes in the direction of X-ray beams due to interactions with the electrons around atoms. It occurs due to elastic scattering, when there is no change in the energy of the waves. ...
*
Synchrotron
References
{{Crystallography
Measuring instruments