Design of the beamline elements in the bessy vsr cold string *

The four SRF cavities in the BESSY VSR module will be linked by bellows, which will be equipped with inner coaxial shielding pipes to prevent both parasitic fundamental mode losses and beam-induced heating. The central bellow will also act as a collimator for synchrotron radiation generated in the closest upstream dipole magnet. Additional bellows at the module's ends are needed to connect with the warm BESSY beam pipe. Outside the module the beam pipe cross section transitions will be located, which will be equipped with toroidal HOM absorbing elements. In the paper the recent design considerations and specifications for all those components will be described.