I summarized the work done regarding the study of the scattered light produced by the output mode cleaner of LHO in the presentation on DCC document G2301690-v1. This could have been one of the candidates of the noise at 20-50Hz caused by the up-conversion of the fast glitches at 2.6Hz. According to this study, the amount of scattered light produced by the OMC could be sufficient to cause noise around those frequencies. Nevertheless, the relative movement between OMC and SRM, when the interferometer is locked, is not sufficient to move the shelf of scattered light into the critical region for the sensitivity curve, as shown in Fig. 1.

In order to perform the study, I used the data taken from Camilla (in the entries 71354, 71742) to find the coupling factor G. I then calculated the scattered light noise considering different gps: in the absence of earthquake, in the presence of earthquake and during a fast glitch at 2.6Hz.  The effect is that this noise remains at low frequency and thus should not cause extra noise in DARM.