What Is a Light Source?
What Is a Light Source?
The light sources in lightsources.org are accelerator-based sources of exceptionally intense, tightly focused beams of x rays and ultraviolet radiation, as well as infrared, that make possible both basic and applied research in fields from physics to biology to technology that are not possible with more conventional equipment.
Speaking broadly, light refers to the electromagnetic (light) spectrum.
The human eye can see visible light, only a small part of this vast spectrum, which also includes radio waves, microwaves, infrared, ultraviolet, x rays, and gamma rays. Those wavelengths of the light spectrum not visible to the human eye are also useful in everyday life. For example, microwave ovens use microwaves to cook your food; a TV remote control uses infrared light to adjust the volume or change the channel of the TV; tanning lamps use ultraviolet light to bronze the skin; and airport scanners use x rays to inspect luggage.
Fig. 1 The electromagnetic spectrum spans the range from radio waves at long wavelengths to gamma rays at short wavelengths. (Courtesy: Advanced Light Source)
At the world’s light sources, our primary interest is in the wavelengths spanning the x-ray and ultraviolet ranges as well as the infrared. We use this light to conduct scientific research. Our thirst for knowledge drives us to explore the world around us. What is our planet made of? What are the processes that sustain life? How can we explain the properties of matter and develop new materials? Will it one day be possible to conquer viruses, predict natural catastrophes or eliminate pollution?
Most of these questions cannot be answered without a profound knowledge of the intimate details of the structure of matter. To help in this quest, scientists have developed ever more powerful instruments capable of resolving the structure of matter down to the level of atoms and molecules. Light sources are one of the most useful of these tools. They can be compared to “super microscopes” with the power to reveal invaluable information in numerous fields of research from physics to biology. There are now more than 50 light source facilities around the world used by more scientists every year, and the number continues to grow.
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