How is the radiation ‘tuned’ in a beamline?
Synchrotron radiation has a very broad spectrum. While some regions of the spectrum can be filtered out, the end user usually wants a single wavelength with a very precisely known value. This selection process is called ‘tuning’. In the case of a beamline, this is done using a device called a ‘monochromator’, which selects a single X-ray wavelength. For the purposes of this Detailed study, students only need to know that this selection process can be achieved by diffraction. The monochromator uses a precisely-cut crystal (often of silicon) and Bragg’s Law to select a particular wavelength (which emerges at a particular angle.
