Numerical dynamical analysis of two types of X-ray baffles onboard EP-FXT mirror assembly

Purpose: In order to evaluate the mechanical feasibility of the domestic baffle made by wire electrode cutting for the mirror assembly of the Follow-up X-ray Telescope (FXT) onboard the Einstein Probe (EP) mission.
Methods: Finite element analysis was performed to compare the structural differences between the domestic baffle made by wire electrode cutting and the eROSITA baffle made by bonding. The finite element models were verified by test data in advance to avoid significant deviations. Finally, the differences in dynamical performances between the FXT mirror assemblies with the two baffles were investigated through modal analysis and frequency response analysis using the pre-verified models.
Results and conclusions: The results show that, from the perspective of the entire mirror assembly, their eigenfrequencies remain similar, except for the second lateral eigenfrequency, which shifts forward by approximately 24 Hz in the mirror assembly equipped with the domestic baffle. However, for the X-ray baffles themselves, the axial and lateral eigenfrequencies of the two baffles differ by approximately 49 Hz and 185 Hz, respectively. These eigenfrequencies are staggered, ensuring that over-response is avoided. In terms of response amplification, the domestic baffle, compared to the eROSITA baffle, exhibits inferior axial mechanical characteristics but superior lateral characteristics. In summary, from a mechanical perspective, the domestic baffle is feasible.