Glossary

Ångström Å

A unit of length equal to 0.1 nanometre (10⁻¹⁰ metre), widely used for distances between atoms. Both the ESRF’s X-rays and the ILL’s thermal neutrons have wavelengths of about this size, which is why they can reveal atomic structure. Read more →

Beam time

Time allocated to a research team on a beamline or neutron instrument. For academic research it is awarded through peer review of proposals: the ESRF’s standard deadlines are 1 March and 10 September, and the ILL, with deadlines in February and September, can accept about half of the requests it receives. Read more →

Beamline

An experimental station at the end of a beam of synchrotron light: a specialised laboratory with its own optics, instruments and support team, built for one kind of measurement. The ESRF has 44 beamlines around its ring. Read more →

Cryo-electron microscopy cryo-EM

A method in which biological molecules are frozen so quickly that they keep their natural shape, then imaged in an electron microscope; many two-dimensional images are combined into a three-dimensional structure. It earned the 2017 Nobel Prize in Chemistry, and on the EPN campus the partners jointly run the CM01 microscope. Read more →

Deuteration

Replacing ordinary hydrogen in a sample with deuterium, the heavy isotope of hydrogen whose nucleus contains a neutron as well as a proton. Neutrons tell the two isotopes apart, so deuterated samples show more clearly in neutron experiments; the EPN campus has dedicated deuteration laboratories. Read more →

EBS Extremely Brilliant Source

The ESRF’s new storage ring, built inside the old tunnel and opened to users on 25 August 2020. Its Hybrid Multi-Bend Achromat magnet layout made the X-ray beams 100 times better in brilliance and coherence; the ESRF calls it the first high-energy fourth-generation synchrotron. Read more →

Electronvolt eV

A unit of energy accepted for use with the SI: the kinetic energy an electron gains when it passes through a potential difference of one volt in vacuum, 1 eV = 1.602 176 634 × 10⁻¹⁹ joule. The ESRF’s electrons reach 6 GeV, six billion electronvolts. Read more →

EMBL Grenoble European Molecular Biology Laboratory, Grenoble site

The Grenoble site of the European Molecular Biology Laboratory, set up in 1975 next to the ILL to study biological problems with neutrons. Today it specialises in structural biology research, instrument development and services, with a focus on RNA and infection biology. Read more →

EPN campus European Photon and Neutron science campus

The shared research site on Grenoble’s Presqu’île of the ESRF, the ILL, EMBL Grenoble and the Institut de Biologie Structurale. The ESRF dates its creation to 2010; the four institutes have worked together in the Partnership for Structural Biology since 2002. Read more →

ESRF European Synchrotron Radiation Facility

The international synchrotron light source in Grenoble, supported by 19 partner countries, Poland among them. Its storage ring is 844 metres round and feeds 44 beamlines, used by more than 9,000 visiting scientists a year. Its convention was signed in 1988. Read more →

IBS Institut de Biologie Structurale

The Institute of Structural Biology, a joint research unit of the CEA, the CNRS and Université Grenoble Alpes, founded in 1992 to use the ESRF and the ILL for structural biology. It studies the structure and dynamics of proteins and moved onto the EPN campus in 2013. Read more →

ILL Institut Laue-Langevin

The international neutron research institute in Grenoble, founded in 1967 by France and West Germany and later joined by the United Kingdom. Its research reactor supplies neutrons to around forty instruments. It is named after the physicists Max von Laue and Paul Langevin. Read more →

Lautaret Garden Jardin du Lautaret

An alpine botanical garden and research support unit of Université Grenoble Alpes and the CNRS at about 2,100 metres, created in 1899 and moved to its present site in 1919. It holds more than 2,000 plant species from the world’s mountains and has a laboratory chalet for research on alpine plants. Read more →

LNCMI Laboratoire National des Champs Magnétiques Intenses

The CNRS national high magnetic field laboratory, with a steady-field site in Grenoble and a pulsed-field site in Toulouse, merged in 2009. Its Grenoble predecessor is where the quantum Hall effect was discovered in 1980. Read more →

Moderator

A material that slows down the fast neutrons released by fission so that they are useful for experiments. At the ILL heavy water both cools the core and moderates the neutrons, from about 20,000 kilometres per second to thermal speeds of about 2.2 kilometres per second; a liquid-deuterium cold source slows some of them further. Read more →

Neutron

An electrically neutral particle found, together with protons, in the nucleus of an atom. Set free, it penetrates deep into materials and, as the ILL puts it, can behave as a particle, as a wave or as a microscopic magnet, which makes it a probe of where atoms are and how they move. Read more →

Neutron crystallography

Determining the atomic structure of a crystal from the way it scatters neutrons. In large biological molecules it can locate hydrogen and deuterium atoms, at a resolution of 1.5 to 2.5 ångströms, at room temperature and without radiation damage. Read more →

Presqu’île

Grenoble’s scientific peninsula, a district close to the city centre between the Isère and Drac rivers. It is home to the ESRF, the ILL, EMBL Grenoble, the IBS and the GIANT innovation campus. Read more →

Quantum Hall effect

In a very thin layer of electrons, very cold and in a strong magnetic field, the Hall resistance rises in flat steps fixed by two constants of nature, Planck’s constant and the electron charge. Klaus von Klitzing discovered it in Grenoble’s high-field laboratory on 4–5 February 1980 and received the 1985 Nobel Prize in Physics; since 2019 it realises the ohm within the SI. Read more →

Research reactor

A nuclear reactor built mainly to produce neutrons for research, not electricity. The IAEA notes that most have an output below 1 megawatt; the ILL’s high-flux reactor, at 58.3 megawatts of heat, is one of the most powerful. Read more →

Scattering

What happens when a beam of X-rays or neutrons hits a sample and is deflected in different directions. The pattern depends on how the atoms are arranged, so it can be used to work out the structure, provided the beam’s wavelength is similar to the distance between atoms, about 0.1 nanometre. Read more →

Small-angle scattering SAXS with X-rays, SANS with neutrons

A technique that measures the scattering of a beam at very small angles, which reveals the size and shape of objects much larger than an atom, such as proteins and polymers. It is done with X-rays and with neutrons; the ILL’s D22 instrument combines both. Read more →

Spallation

A way of freeing neutrons without a reactor: heavy atomic nuclei are struck by high-energy protons from an accelerator and shed neutrons. Spallation sources give pulsed beams; the ILL notes that they do not match its reactor’s time-averaged flux. Read more →

Storage ring

The main ring of a synchrotron, in which electrons circulate for hours inside a pipe kept at ultra-high vacuum. At the ESRF it is 844 metres round and built from 32 repeating cells of magnets that steer and focus the beam. Read more →

Structural biology

The science of determining the three-dimensional shapes of biological molecules such as proteins, DNA and RNA, atom by atom, and of how those shapes change as the molecules work. In Grenoble it is done with X-rays, neutrons and electron microscopes on the EPN campus. Read more →

Synchrotron

A particle accelerator that keeps electrons circling a ring at almost the speed of light and bends their path with magnets, so that they give off intense light, mostly X-rays. Scientists use that light to study the structure of matter. The ESRF in Grenoble is a synchrotron. Read more →

Synchrotron light synchrotron radiation

The radiation given off by electrons moving at almost the speed of light when magnets force them to change direction. At the ESRF it is mostly X-rays with a wavelength of about 0.1 nanometre, roughly the size of an atom, and far brighter than X-rays used in hospitals. Read more →

Undulator

A row of small magnets with alternating poles, placed in a straight section of a storage ring, that makes the electrons wiggle as they pass. The ESRF says undulators give X-rays a million times more intense than bending magnets. Read more →

Université Grenoble Alpes UGA

Grenoble’s university, whose history goes back to 1339, when it was founded by the Dauphin Humbert II. In its present form, bringing together the university, engineering schools and research bodies, it was established on 1 January 2020. Read more →

White coal houille blanche

A French name for hydropower, popularised in 1882 by Aristide Bergès, who drove his paper mill at Lancey with water from the Belledonne mountains. Alpine water power made Grenoble a centre of electrical engineering, celebrated at the 1925 International Exhibition of Hydropower and Tourism. Read more →

Sources checked on: 3 November 2026