Comparison of Calibration Epics Values (Calibration parameters at t = t0) during O1 and ER9.
Param. Description 2015/09/29 2016/08/03 2016/08/10
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EP1 ~1/Atst0 (ftst) 2.2005e+16 2.1066e+16 4.9121e+17
EP2 ~Delta C/(1+G) 0.9895 0.9934 0.9934
EP3 1/Apu0 (fctrl) 2.1115e+16 2.1077e+16 2.1077e+16
EP4 Atst0 (fctrl) 5.4972e-17 5.6354e-17 5.6354e-17
EP5 Apu0 (fctrl) 4.7360e-17 4.7446e-17 4.7446e-17
EP6 Cres(fpcal2) 1.1307e+06 8.9859e+05 8.9859e+05
EP7 D0(fpcal2) 1.7599e+07 1.5871e+11 1.5871e+11
EP8 Atst0 (fpcal2) 1.2178e-18 1.13718e-18 1.13718e-18
EP9 Apu0 (fpcal2) 2.0898e-19 2.0235e-19 2.0235e-19
The numbers in the first column are from O1. The numbers in second and third column are ER9 values. All values in column 2 and column 3 are same except EP1. There was dicrepancy in this value because we changed the way the tst line was injected during ER9 (compared to O1) and didnot account properly for the change. However, EP6 and EP7 values changed significatly between O1 and ER9. Change in EP6 accounts for the change in optical gain and is real. However 4 order of magnitude change in EP7 looks fishy.
Evan H., Darkhan T.,
Details
SUS-ETMY_LKIN_P
(see LHO alog 28164). Later we found that the amplitude of this line in the DARM spectrum recorded during ER9) was unsufficient for tracking the ESD actuation strength. So, the EPICS values for time-dependendent factors were recalculated on Aug 10 for using a calibration line injected fromSUS-ETMY_L3_CAL_LINE
.The transfer function for the
SUS-ETMY_L3_CAL_LINE
line includesDRIVE_ALIGN
filter, which is not the case for a line injected fromSUS-ETMY_LKIN_P
. The gain of this filter at cal. line frequency is ~22, this explainsEP1
value change.EP6
).EP7
(D0 at 331.9 Hz), could be that during ER9 we, by mistake, did not turn on the notch at 331.9 Hz. In O1 run this notch was inLSC-DARM
, FM7 (see LHO alog 20075). After adding a second set of filter modules (nowLSC-DARM1
andLSC-DARM2
) the notch was moved toLSC-DARM2
, FM4, but was not turned on during ER9.Note:
LSC-DARM2
, FM4 will be turned on during nominal low-noise operation in ER10/O2 (must not forget to include this into Matlab DARM model).