Advanced Photon Source
Encyclopedia
Argonne National Laboratory
Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
(in Argonne, IL, USA) is a national synchrotron
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronised with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...
-radiation light source research facility funded by the United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
Office of Science
Office of Science
The Office of Science is a component of the United States Department of Energy . The Office of Science is the lead federal agency supporting fundamental scientific research for energy and the Nation’s largest supporter of basic research in the physical sciences...
. Argonne National Laboratory is managed by UChicago Argonne LLC, which is composed of the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
and Jacobs Engineering Group, Inc.
Using high-brilliance X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
beams from the APS, members of the international synchrotron-radiation research community conduct forefront basic and applied research in the fields of materials science
Materials science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...
and biological science; physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
; environmental
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....
, geophysical and planetary science
Planetary science
Planetary science is the scientific study of planets , moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation,...
; and innovative X-ray instrumentation.
How APS works
ElectronElectron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s are produced by a cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
that is heated to about 1,100°C (2,000°F). The electrons are accelerated to 99.999% of the speed of light in a linear accelerator. From the linear accelerator, the electrons are injected into the booster synchrotron
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronised with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...
. Here, the electrons are sent around an oval racetrack of electromagnets, providing further acceleration. Within one-half second, the electrons reach 99.999999% of the speed of light. Upon reaching that speed, the electrons are injected into the storage ring, a 1,104 meter (3 622 ft) circumference ring of
more than 1,000 electromagnets.
Once in the storage ring, the electrons produce x-ray beams that are available for use in experimentation. Around the ring are 40 straight sections. One of these sections is used to inject electrons into the ring, and four are dedicated to replenishing the electron energy lost though x-ray emission by using 16 radio-frequency accelerating cavities. The remaining 35 straight sections can be equipped with insertion devices. Insertion devices, arrays of north-south permanent magnets usually called "undulator
Undulator
An undulator is an insertion device from high-energy physics and usually part of a largerinstallation, a synchrotron storage ring. It consists of a periodic structure of dipole magnets . The static magnetic field is alternating along the length of the undulator with a wavelength \lambda_u...
s", cause the electrons to oscillate and emit light in the invisible part of the electromagnetic spectrum. Due to the relativistic velocities of the electrons, that light is Lorentz-contracted into the x-ray band of the electromagnetic spectrum
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
.
The Experiment Hall surrounds the storage ring and is divided into 35 sectors, each of which has access to x-ray beamline
Beamline
In particle physics, a beamline is the line in a linear accelerator along which a beam of particles travels. It may also refer to the line of travel within a bending section such as a storage ring or cyclotron, or an external beam extracted from a cyclic accelerator.In materials science, physics,...
s, one at an insertion device, and the other at a bending magnet. Each sector also corresponds to a lab/office module offering immediate access to the beamline.