[Robert, Giacomo]

In the past few week we have alwayis notice a ~1 h period variation in the IMC-REFL power during IMC locks. We suspected that it has something to do with the temperature, but only this morning Robert forced me to take 5 minutes and look into it. There is a clear correlation between PSL room temperature and IMC-REFL power (i.e. alignment into the IMC) at and below about 1 mHz (no surprise).

Attached are data taken during an IMC lock at UTC 2013-01-25 04:30:00 (GPS = 1043123416)

- time series of the IMC REFL power (H1:IMC-REFL_DC_OUT_DQ) and the four temperature sensors in the PSL room (H1:PSL-ENV_LASERRM_[ACN/ACS/TBLN/TBLS]_TEMP_DEGC)

- transfer function and correlation between each of the temperature channels and IMC-REFL

TBLS (not surprising as the periscope is right there) and ACN (not sure where this sensor is...) show the biggest corelation with the IMC_REFL power.