We tested the mechanical rigidity of an accelerometer mount consisting in gluing the aluminum cube to the vacuum vessel. We tested it at the WI-BS link comparing two accelerometers (PCB 393B12) attached to their own alumimum cube, one cube being bolted  to one vessel eyelet and one glued directly on the vessel (see picture in Figure 1). We used Loctite 454 glue and treated with sandpaper both surfaces. The glued side of the cube has been machined in a "V" shape in order to improve the contact with the curved surface of the vessel.

The measured transfer function is flat up to about 400Hz (Figure 2). Above 400Hz the measurement is not good, yet it is sufficient for our purposes. Having already tested that the mount consisting of the bolted alumium cube is rigid (i.e. it moves rigidly with the surface it is attached to) up to about 300Hz, we can trust both accelerometer mounts (glued cube or bolted cube) will measure accurately vessel vibrations up to at leat 300Hz.