- CMS measurement
Though there was some conflict between the modification history by Nakano-kun (klog#11454) and Wiki page I was able to confirm klog information was latest. (But C275 and C279 should be NL and 47n, respectively)
Figure 1 shows the measured fitted main filter in FAST path.
According to the fitting results, filter characteristic is BPF from 2.44kHz to 38.7kHz with 1.01 as pass band gain.
(Design values coming from circuit diagram are BPF 2.26kHz to 36.2kHz with 1.0 as pass band gain.)
All measured data are stored in /users/Commissioning/data/IMC/2021/0414
- Expected OLTF model
By using the measured CMS TFs and guardian information, I constructed the OLTF model of IMC (see figure 2).
Many parameters are referred by past measurements yet.
- PZT efficiency: klog#13012
- MCE actuator efficiency: klog#14562
- Optical gain & cavity pole: klog#14569
- EOM efficiency: I cannot found klog post. So adjustting the UGF to be around 130 kHz (see also klog#11475).
- Temperature loop efficiency: I cannot found klog post. Sloppy.
According to guardian code, MCE output is held at IMC_MCL_SERVO_OUT in ENGAGE_BOOST state.
(In my remember, it was held after IMC_LSC_LOCK state... Am I mistaken?)
