Systematic opto-mechanical design approach for meter-long Nano-AKB mirror system at HEPS

A systematic opto-mechanical design approach is developed for a long Nano-AKB mirror system aimed at stable sub-50 nm hard X-ray nanofocusing. The approach integrates deformation-stiffness-balanced mirror clamping, hierarchical precision alignment, and thermomechanical stability management and has been applied to nanofocusing instruments at HEPS. During beamline commissioning at HEPS ID19, the system achieved a focal spot of 34.6 ± 1.31 nm × 41.6 ± 0.67 nm (H × V) at 20 keV while maintaining Z-displacement stability below 5 nm RMS. The results meet the design expectations, strongly attesting to the efficacy and practical viability of the proposed approach.