The ELETTRA linac to storage ring transfer line

The injection system for the ELETTRA storage ring is a full-energy linear accelerator (linac). It will be located underground outside the storage ring so as not to interfere with the experimental area. It will be constructed and operated in two stages: 1.5 GeV (for initial user operation) and 2 GeV (for final operation), with the option of conversion for positrons in a later stage. To obtain a small beam size as well as to implement many of identical elements, the structure of the transfer line consists of four achromatic arcs, three in the horizontal and one in the vertical direction. The matching between the achromatic arcs is performed with triplet and FODO systems. The longest transfer line (1.5 GeV) with a length of 103 m needs 30 quadrupoles, 7 bending magnets and 34 steerer magnets. The largest beam size obtained throughout the transfer line is +or-12 mm for electrons and +or-17 mm for positrons. to get 95% of the particles (2 GeV-positrons) through the transfer line and considering misalignment errors, the aperture of the magnetic elements has to be +or-25 mm.<>