A non-standard, but competitive, lattice solution for a 4th generation light source with capabilities for metrology applications & timing

Abstract HZB is working on a concept for a BESSY II successor, based on a 4 th generation light source with an emittance of 100 [email protected] GeV. The PTB, Germany’s national metrology institute, has relied on synchrotron radiation for metrology purposes for over 40 years and the most prominent customers are lithography systems from ASML/ZEIS. It is essential, that this new facility continues to serve the PTB for metrology purposes. This sets clear boundary conditions for the lattice design, particularly the need for a homogeneous bend as a metrological radiation source. Different Higher-Order-Multi-Bend-Achromat lattices have been developed, based on combined function gradient bends and homogeneous bends in a systematic lattice design approach. All lattices are linearly equivalent with the same emittance and maximum field strength. However, they differ significantly in their non-linear behavior. Based on this analysis, the choice of the BESSY III lattice type is motivated. A special focus is set also on TRIBs (Transverse Resonance Island Buckets) to operate with two orbits as a bunch separation scheme in MBAs, for different repetition rates or for the separation of short and long bunches.