A beamline is a complex structure which transfers the radiation emitted from a synchrotron source to an experimental chamber.
The radiation energies, emitted by the electrons traveling at relativistic speed in a synchrotron ring, range from hard X-ray to infrared light. Generally a beamline is mainly composed of mirrors, diaphragms and monochromator ultra high vacuum (UHV) chambers. Mirrors chambers contain mirrors used for radiation focusing and diverting. Diaphragms chambers contains highly precise variable dimension apertures defining the collected portion of the radiation fan.
Monochromators chambers contain one or more diffraction elements able in dispersing the incident radiation in its energies components. All the chambers are connected via pipes, bellows and fittings. Inside the entire length of a beamline a pressure of about 10-10 mbar has to be maintained in operative conditions.
Total beamline length can reach 30 m or more.
The principal challenges in the realization of a beamline are the design, manufacturing and tests of high precision mechanical motion systems, that can be mounted inside or outside the vacuum chambers. The assembly must guarantee up to six degrees of freedom position mechanisms (less than 0.1 μm of linear positioning precision and less than 0.1 μrad of angular one) with the aim of precisely managing the positions of the optical elements along the radiation path (example of optical elements are: diffraction gratings or crystals, spherical or non spherical mirrors, with a linear dimensions up to 1200 mm). These motion systems can be manually or motor driven with integrated computer controls.
Because of beam’s high energy, the optical elements are often cooled using water or liquid helium circuits which must preserve both UHV environment and elements’ motion possibilities.
Samples of past TEES realizations in this field are shown in the gallery: