Tolerance-budgeting for ultra-stable KB systems

The emergence of new-generation light sources has driven experimental stations and optomechanical instrumentation to increasingly ambitious designs: precision engineering, optics design, and experimental techniques are being pushed to the limit of what is achievable, targeting the best spatial, spectral, and temporal resolution for their measurements. The extreme brilliance making diffraction-limited focusing feasible, also sets new sensitivity baselines for vibrations, clamping and thermal deformations, demanding stiffer mechanics and tighter tolerances for fabrication, metrology, assembly, and alignment, as well as creative commissioning and experiment control strategies. Such interdisciplinary design often requires cross-checking between mechanical, optical, and experimental specifications, where shared variables such as mirror dimensions, incidence angle, and optical magnification factor might induce conflicting behaviour, especially when tightly bounded to pioneering design targets on focus size and divergence, working distance, and flux density to name a few, stressing specifications and tolerances throughout every design step. In this manner, an analytical model integrating the main mirror tolerances could act as a more assertive starting point to broader, model-based assessments, pruning the decision space for subsequent finite-element analysis targeting globally optimal designs. This contribution suggests a tolerance budgeting approach for designing ultra-stable KB mirror systems, which in turn authorized an exactly-constrained realization [5], providing the high stability needed for ambitious nanoprobe designs, as the example of recently commissioned tarumã station, from Sirius/lnls carnaúba beamline [8], and underway designs such as mogno and sapoti stations also at Sirius.