J. Kissel

According to this morning's measurement of the DARM OLG TF (LHO aLOG 18352), comparing model against measurement -- which recall has a ~2.5%, 1 [deg] precision (see LHO aLOG 18186) -- the DARM Coupled Cavity Pole (DCCP) frequency was 303 [Hz]. 

Just to refresh everyone's memory, since the DCCP's frequency has been constantly evolving, I list below the measurement times and the resulting DCCP frequency for all measurements thus far. As mentioned in LHO aLOG 18352, now my goal to data mine as much information as I can, similar to what Kiwamu has done for just two of these measurements, see LHO aLOG 18298.

     Date UTC               DCCP Frequency [Hz]
'Mar 10 2015 03:41:52 UTC'        320
'Apr 02 2015 08:34:20 UTC'        320
'Apr 06 2015 23:45:13 UTC'        320
'Apr 13 2015 04:15:43 UTC'        290
'Apr 13 2015 06:49:40 UTC'        290
'Apr 15 2015 07:53:56 UTC'        290
'May 01 2015 18:52:59 UTC'        355
'May 02 2015 20:35:54 UTC'        355
'May 06 2015 11:37:31 UTC'        270
'May 07 2015 07:08:12 UTC'        260
'May 11 2015 15:50:43 UTC'        303


The attached comparison only shows the latest 5 of these measurements for clarity, because they extend out to the largest frequency range, increasing the confidence in the DCCP frequency.

Note this is also the reason why we've held off on updating the calibration of the CAL-CS (and therefore the GDS low-latency pipeline).