DESY, short for Deutsches Elektronen-Synchrotron, is a national research centre for fundamental science located in Hamburg and Zeuthen near Berlin in Germany. It operates particle accelerators used to investigate the structure, dynamics and function of matter, and conducts a broad spectrum of interdisciplinary scientific research in four main areas: particle and high energy physics; photon science; astroparticle physics; and the development, construction and operation of particle accelerators. Its name refers to its first project, an electron synchrotron. DESY is publicly financed by the Federal Republic of Germany and the Federal States of Hamburg and Brandenburg and is a member of the Helmholtz Association.
An attosecond is a unit of time in the International System of Units (SI) equal to 10−18 or 1⁄1 000 000 000 000 000 000 of a second. An attosecond is to a second as a second is to about 31.71 billion years. The attosecond is a tiny unit but it has various potential applications: it can observe oscillating molecules, the chemical bonds formed by atoms in chemical reactions, and other extremely tiny and extremely fast things.
Christian Boehmer Anfinsen Jr. was an American biochemist. He shared the 1972 Nobel Prize in Chemistry with Stanford Moore and William Howard Stein for work on ribonuclease, especially concerning the connection between the amino acid sequence and the biologically active conformation.
A free-electron laser (FEL) is a fourth generation light source producing extremely brilliant and short pulses of radiation. An FEL functions much as a laser but employs relativistic electrons as a gain medium instead of using stimulated emission from atomic or molecular excitations. In an FEL, a bunch of electrons passes through a magnetic structure called an undulator or wiggler to generate radiation, which re-interacts with the electrons to make them emit coherently, exponentially increasing its intensity.
Photosystems are functional and structural units of protein complexes involved in photosynthesis. Together they carry out the primary photochemistry of photosynthesis: the absorption of light and the transfer of energy and electrons. Photosystems are found in the thylakoid membranes of plants, algae, and cyanobacteria. These membranes are located inside the chloroplasts of plants and algae, and in the cytoplasmic membrane of photosynthetic bacteria. There are two kinds of photosystems: PSI and PSII.
Photosystem II is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol. The energized electrons are replaced by oxidizing water to form hydrogen ions and molecular oxygen.
Photosystem I is one of two photosystems in the photosynthetic light reactions of algae, plants, and cyanobacteria. Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the moderate-energy hydrogen carrier NADPH. The photon energy absorbed by Photosystem I also produces a proton-motive force that is used to generate ATP. PSI is composed of more than 110 cofactors, significantly more than Photosystem II.
The oxygen-evolving complex (OEC), also known as the water-splitting complex, is a water-oxidizing enzyme involved in the photo-oxidation of water during the light reactions of photosynthesis. OEC is surrounded by 4 core proteins of photosystem II at the membrane-lumen interface. The mechanism for splitting water involves absorption of three photons before the fourth provides sufficient energy for water oxidation. Based on a widely accepted theory from 1970 by Kok, the complex can exist in 5 states, denoted S0 to S4, with S0 the most reduced and S4 the most oxidized. Photons trapped by photosystem II move the system from state S0 to S4. S4 is unstable and reacts with water producing free oxygen. For the complex to reset to the lowest state, S0, it uses 2 water molecules to pull out 4 electrons.
Wolfram Saenger is a German biochemist and protein crystallographer. In his research career spanning over 30 years he has worked at the Max Planck Institute for Experimental Medicine, Harvard University and the Free University of Berlin, where he led the Institute for Crystallography research until his retirement in 2011. A recipient of the Gottfried Wilhelm Leibniz Prize (1987) of the Deutsche Forschungsgemeinschaft, which is the highest honor awarded for achievements in research in Germany, and the Humboldt Prize (1988), he is best known for his research on X-ray crystallography of membrane proteins and protein-nucleic acid complexes. He has authored 10 books, including the venerated book 'Principles of Nucleic Acid Structure' published by Springer, and over 500 scientific articles.
The European X-Ray Free-Electron Laser Facility is an X-ray research laser facility commissioned during 2017. The first laser pulses were produced in May 2017 and the facility started user operation in September 2017. The international project with twelve participating countries; nine shareholders at the time of commissioning, later joined by three other partners, is located in the German federal states of Hamburg and Schleswig-Holstein. A free-electron laser generates high-intensity electromagnetic radiation by accelerating electrons to relativistic speeds and directing them through special magnetic structures. The European XFEL is constructed such that the electrons produce X-ray light in synchronisation, resulting in high-intensity X-ray pulses with the properties of laser light and at intensities much brighter than those produced by conventional synchrotron light sources.
An X-ray laser can be created by several methods either in hot, dense plasmas or as a free-electron laser in an accelerator. This article describes the x-ray lasers in plasmas, only.
The Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m. b. H., abbreviated BESSY, is a research establishment in the Adlershof district of Berlin. Founded on 5 March 1979, it currently operates one of Germany's 3rd generation synchrotron radiation facilities, BESSY II. Originally part of the Leibniz Association, BESSY now belongs to the Helmholtz-Zentrum Berlin.
SwissFEL is the X-ray free-electron laser at the Paul Scherrer Institute (PSI), which was inaugurated in December 2016.
Ultrafast X-rays or ultrashort X-ray pulses are femtosecond x-ray pulses with wavelengths occurring at interatomic distances. This beam uses the X-ray's inherent abilities to interact at the level of atomic nuclei and core electrons. This ability combined with the shorter pulses at 30 femtosecond could capture the change in position of atoms, or molecules during phase transitions, chemical reactions, and other transient processes in physics, chemistry, and biology.
John Charles Howorth Spence ForMemRS HonFRMS was Richard Snell Professor of Physics at Arizona State University and Director of Science at the National Science Foundation BioXFEL Science and Technology Center.
Serial femtosecond crystallography (SFX) is a form of X-ray crystallography developed for use at X-ray free-electron lasers (XFELs). Single pulses at free-electron lasers are bright enough to generate resolvable Bragg diffraction from sub-micron crystals. However, these pulses also destroy the crystals, meaning that a full data set involves collecting diffraction from many crystals. This method of data collection is referred to as serial, referencing a row of crystals streaming across the X-ray beam, one at a time.
Henry N. Chapman FRS is a British physicist and the founding director of the Center for Free-Electron Laser Science at the German Electron Synchrotron (DESY). He has made numerous contributions to the field of x-ray coherent diffraction imaging and is a pioneer of the diffraction before destruction technique that allows to analyze biological samples with intense, ultrafast x-ray light, such as Photosystem II, a key macromolecule in photosynthesis.
Alexandra Ros is a German analytical chemist who is a professor in both the School of Molecular Sciences and Center for Applied Structural Discovery at The Biodesign Institute, Arizona State University. Her research considers microfluidic platforms and their use in analysis. She was awarded the 2020 Advancing Electrokinetic Science AES Electrophoresis Society Mid-Career Achievement Award.
The School of Molecular Sciences is an academic unit of The College of Liberal Arts and Sciences at Arizona State University (ASU). The School of Molecular Sciences (SMS) is responsible for the study and teaching of the academic disciplines of chemistry and biochemistry at ASU.
Janos Hajdu is a Swedish/Hungarian scientist, who has made contributions to biochemistry, biophysics, and the science of X-ray free-electron lasers. He is a professor of molecular biophysics at Uppsala University and a leading scientist at the European Extreme Light Infrastructure ERIC in Prague.
