I took some time during today's maintenance to attempt to measure the bounce/roll modes of the HSTS (with Jenne's help) in order to better identify some lines which are present in DARM spectra.

The obtained data is located in the SUS svn:

• /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PR2/SAGM2/Data/
• /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/SAGM2/Data/
• /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/SAGM2/Data/
• /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM2/Data/

To do these measurements I used the already existent DTT templates located in the each SUS svn directory (after turning off the damping on each of the optics).

I have been unable to measure any bounce or roll mode: below 10 Hz, the data looks similar to the reference data, but above 10 Hz there seems to be some kind of noise which contaminates the measurements (although the coherence looks fine). This happens with the four optics, and driving with L_EXC, P_EXC or Y_EXC. The attachments show a couple of examples which show this behaviour. Sheila suggested that this noise might be coming from some cross-coupling of the cables driving/sensing the signals.