Frequently asked questions (FAQ) on Synchrotron Light

To gain Synchrotron Light, electrons have to be accelerated to near light speed, inside an electron accelerator. Magnetic fields there force the flying electrons into a circular orbit. The electrons react to this force with the emission of electromagnetic radiation, called Synchrotron Light.

The spectrum of this Synchrotron Light is shifted towards short wavelengths due to the Doppler effect of a moving light source. In the case of SLS the spectrum ranges from infrared light to soft and hard X-rays.

To make an efficient Synchrotron Light Source one arranges many magnets into a storage ring, where the high energy electrons can circulate for hours. In a socalled undulator one has a periodic array of magnets with alternating polarity of the magnetic field. This forces the electrons into a slalom course. This in turn concentrates the synchrotron light into discrete wavelenghts, a brilliant light beam. Contrary to X-rays, produced in a conventional X-ray tube, the intense synchrotron light beams are sharply focused like a laser beam.

The synchrotron light is guided tangentially away from the storage ring through beamlines to different experimental hutches. Each experimental group has control over its own undulator and can select thus its own wavelength.

With light beams of a long wavelength one can probe the surfaces of new structures, whereas with the penetrating X-rays one examines more the bulk properties of novel materials. Among the many research topics at the SLS are:

• the structure of protein crystals; this is important for the development of new drugs and for understanding the human genome
• magnetic properties of surfaces, leading e.g. to compact magnetic data storage systems
• surfaces with low friction
• catalytic surfaces
• solar cells
• high temperature superconductors
• new materials relevant for environmental or energy issues
• high resolution microscopy on surfaces
• tracing minuscule contaminations on surfaces
• spectroscopic analysis of atoms
• 3d-imaging (micro-tomography) of biological materials
• determination of crystal structures for mineralogy, chemistry, catalysis etc.