The Sirius injection system consists of a 150 MeV linear accelerator (LINAC), an Injector Accelerator ring (Booster) that accelerates the electron beams to the operation of energy of Storage Ring and two transport lines, one from LINAC to Booster (LTB) and one from Booster to Storage Ring (BTS). The injection system works in top-up mode, that is, the electron beams are continuously injected into the Storage Ring.
The Magnetic Lattice of the Booster consists of 50 modified FODO cells with magnets suitable to produce low emittance beams.
The main difference between this design and other Boosters is that it contains only of arc sections, with no long dispersion-free straight sections. The full circumference of 496.8 meters has plenty of component-free straight segments of about 4 meters. Thus, both injection and extraction, as well as the RF cavity are located in those segments. This concept allows the construction of a highly symmetrical magnetic system with the need for only a few families of magnets.
The Booster and Storage Ring are concentric and share the same tunnel, thus the high symmetry of the Lattice also allows the maximization of the radial distance between the Storage Ring and the Booster, minimizing the variation in size of the corridor between the two concentric rings.
The natural emittance obtained in the Booster at the extraction energy of 3 GeV is very low – 3.47 nm.rad – which is essential to provide a good injection into the Storage Ring with the injection process by the Multipolar Pulsed Magnet.