Following sprb scattered light investigations,  yesterday afternoon we put  3 meggit accelerometers in orthogonal configuration on the SPRB link pipe: see picture in Figure 1. The accelerometers are screwed on one  support cube whose "V" shaped face is glued with ciano-acrilic glue to the pipe (as done for other links). Channels are named ENV_SPRB_LINK_ACC_Z,Y,X (Z is along beam, Y is vertical).

Figure 2. As a first check, we find that the Z channel is essentially unchanged with respect to when the accelerometer Z was in the nearby position (see elog 37232).

Figure 3. Compares the three axis. The 55hz structure is a bit more pronounced in X. While the 70Hz to 200Hz motion is amplified in the Z direction.

We tried to excite resonances by hitting the window flange:

• hitting along X (radial direction) we excite significantly a mode at 55 Hz: Figure 4
• hitting along Z (beam) again the 55Hz gets excited but also sometingh around 200Hz and the 50-200Hz region gets enhanced: Figure 5.