In the AEI-SAS, most components wer

In the AEI-SAS, most components were built from aluminium for historical reasons: the aluminium HAM optical table was reused for HAM-SAS, therefore everything was made of aluminium. When the HAM-SAS design was converted to the AEI-SAS, the optical table and the base plate materials were changed to stainless steel, but not the intermediate plate and spring box. For more rigidity, stainless steel should be used for all large plates.The blades of the GAS filters have a sharp resonant mode around 300Hz, depending on the tuning of the individual blades. Instead of using eddy-current damping, a resonant damping approach is conceivable. For that a small mass on a flexible rod (for example made of Viton ® ) can be clamped to the blade without machining it. By changing the length of the rod, the resonance frequency of the damper can be tuned to the exact resonance of each blade.The GAS filters are subject to thermal fluctuations and hysteresis. Especially when heated, the blades become softer. Thus, the GAS filters could be actively actuated by locally heating the blades to compensate for thermal drift and hysteresis effects.The intermediate plate was found to be rather soft at its fundamental bending modes. The plate exists in the AEI-SAS mainly due to historical reasons. In future designs the plate could be omitted. The optical table would then be placed directly on the GAS filters.The aluminium spring box is supposed to be a rigid structure supporting the GAS filters. Instead of bolting the spring box plates together, they should be welded to provide more rigidity.Alternatively, the spring box could be omitted completely, by connecting the GAS filters directly to the IP legs. Thereby the GAS filters could be placed upside-down and bolted directly to the optical table. The key stones would be placed directly on top of the IP legs. This would save vertical space and reduce horizontal GAS filter compliance coupling to the optical bench. However, in this configuration the tilt restoring force would be very low and a tilt stabilizer would become essential.