A Brief History of the NSLS

Initial construction of the National Synchrotron Light Source (NSLS) began in 1978.

The "Phase II" construction project began in 1986, expanding the NSLS by 52,000 square feet, adding much needed offices, laboratories and room for new experimental equipment.

First visible light for machine testing emerges from the NSLS Vacuum Ultraviolet ring in 1982.

Birth of the synchrotron

In 1945, the synchrotron was proposed as the latest accelerator for high-energy physics, designed to push particles, in this case electrons, to higher energies than could a cyclotron, the particle accelerator of the day. An accelerator takes stationary charged particles, such as electrons, and drives them to velocities near the speed of light. In being forced by magnets to travel around a circular storage ring, charged particles tangentially emit electromagnetic radiation and, consequently, lose energy. This energy is emitted in the form of light and is known as synchrotron radiation.

The General Electric (GE) Laboratory in Schenectady built the world's second synchrotron, and it was with this machine in 1947 that synchrotron radiation was first observed. Radiation by orbiting electrons in synchrotrons was predicted by, among others, John Blewett, then a physicist for GE who went on to become one of Brookhaven's most influential accelerator physicists, working on both the Cosmotron and the Alternating Gradient Synchrotron.

For high-energy physicists performing experiments at an electron accelerator, synchrotron radiation is a nuisance which causes a loss of particle energy. But condensed-matter physicists realized that this was exactly what was needed to investigate electrons surrounding the atomic nucleus and the position of atoms in molecules. So, in the early days, the two branches of physics worked together in so-called "parasitic" operation, where synchrotron light illuminated the condensed-matter physicists' experiments while particle physicists used the electron beam.

The light spectrum

The part of the electromagnetic spectrum that the human eye can see is called visible light. In order of decreasing wavelength and increasing frequency, it is known to school children as "ROY G. BIV," for red, orange, yellow, green, blue, indigo and violet. The region with wavelengths shorter than violet is the ultraviolet and, overlapping and going beyond it, the x-ray region. Meanwhile, on the other side of red, with longer wavelengths, is the infrared region. The shorter the wavelength, the higher the frequency and the more "energetic" the light. While it cannot be seen by the human eye, when used in certain ways and viewed by appropriate detectors, this light can reveal structures and features of individual atoms, molecules, crystals, cells and more, especially when the wavelength and corresponding energy of the light are matched to the size and energy of the sample being viewed. Because synchrotron light is very intense and well collimated, it is preferred to light produced by conventional laboratory sources.

Decision to build the NSLS

When the U.S. Department of Energy's Office of Basic Energy Sciences recognized the need for "second generation" electron synchrotrons dedicated to the production of light, it budgeted construction funding for Brookhaven's National Synchrotron Light Source (NSLS), beginning in fiscal year 1978. Ground was broken for the NSLS on September 28, 1978, and the vacuum ultraviolet (VUV) ring began operations in late 1982, while the x-ray ring was commissioned in 1984. 

The Chasman-Green lattice

Before the light at the NSLS was turned on, however, the two inspired scientists responsible for the ingenious design of the two storage rings had died. The late Renate Chasman and G. Kenneth Green had designed the "double focusing achromat," or what is more commonly known as the Chasman-Green lattice. The lattice is the periodic arrangement of magnets that bend, focus and correct the electron beam, and their simple yet elegant design included straight sections for the insertion of equipment.

When special magnets are inserted into two straight sections in the VUV ring and five straight sections in the x-ray ring, the electron beam "wiggles" and, therefore, emits even more intense synchrotron radiation. Chasman and Green's inclusion of these devices in their design of the storage rings enables the NSLS to deliver world-class beams of light today.