Interesting data (Interesting data)swinkels, derosa - 17:19 Tuesday 04 August 2009 (24064)
Print this reportChange of finesse asymmetry during earthquake??When the ITF was locked again after yesterday's eartquake, the finesse asymmetry had changed considerably. This can be seen directly in the calculated finesse asymmetry (Alp_Gc_DF) and in beta (Gc_Driving_PRCL_NE-WE). Also the ratios of DC powers B7/B5 and B8/B5 seem to indicate that the finesse of both arms has changed considerably, see attached plot. This seems not related to any etalon effect: no change in TCS power and rotor-postion is visible and no change in temperature of the ovens. Moreover, the transient seems too fast to be a change of the mirror temperatures. Maybe it is not really the finesse that is changing, but something else like the aligment of the input beam or some bench, but nothing obvious has yet been found.
The only other strange thing happening at the same time is a change of the temperature of the OMC by 0.2 degrees. Also this is not normal. Anyone has an idea what is going on here?
