The B1 setup is exactly the same (see picture). The only difference is the length of the optical path in air. Before: 120cm. Now: 55cm.
Looking at the sensitivity in this configuration, there seems to be no difference apart from 2 small structures at 65 and 220Hz, which are mechanical resonances of the small tower as seen by the seismometer SETODE01. There is clear coherence (see plot).
Note:
In order to reconnect as before: d2 cable <-> d44 photodiode, d4 cable <-> d41 photodiode.
