The aim of the shift was to characterize the OLTF of 3f signals in CITF. 

We begin our shift with the usual prealignement procedure for the CITF:

PREalignment:

•     Reminder: Before alignment we need to open the drift control for SDB1. So inside the SDB1_LC process we have to click on 'Open B5 beam drift'. 
•     NE, WE misaligned using NARM and WARM metatron nodes.
•     Check recombination alignment on B1p_camera by moving BS_TX and BS_TY.
•     PR aligned to Tx = -36.6 urad Ty = 1.1 urad and fine-tuned to Tx = -38.4 urad Ty = -6.4 urad using B1p camera. We saved this position in metatron's SUS_PR.ini file by hand, just to avoid errors seen in the previous shifts.
•     PR misaligned to Tx = -37.45 urad Ty = -66.5 urad using PR metatron node (MISALIGNED state).
•     SR aligned to Tx = 76.37 urad Ty = -193.3 urad and fine-tuned to Tx = 65.8 urad Ty = -240 urad using B1p camera. Values saved using metatron's SAVE_ALIGNED state of SUS_SR.    
•     PR realigned using PR metatron node (ALIGNED state), which uses previously saved values in step 2.

At 15.39 UTC, we engaged the DRMI lock using CITF_init.py script. But the lock did not engage even when we had optimal alignment and triggers (see fig 1). For this reason, Romain checked the B2_PD3 photodiode for any sign of clipping and confirmed that it was ok. But soon afterwards, we observed oscillations in PR_TX and PR_TY (see fig 2). 

Paolo damped the oscillations observed in PR, and after some alignment of CITF, we immediately locked the DRMI at 19.35.18 UTC (see fig 3) (where we kept the threshold to 70% of the max B4_112MHz and B4_12MHz).  We took clean data of the 1f DRMI lock till 19.36.50 UTC. 

Then, we engaged the drift controls of PR_TX, PR_TY, and then full bandwidth loops of PR mirror and took some clean data: 

• Engage of PR_TX            19.36.50 UTC 
• Engage of PR_TY            19.37.50 UTC 
• Engage of PR_FB            19.39.45 UTC 

We handed off to 3f at 19.41.30 UTC.

Taking the reference from fig 4 for the shape of the noise, we injected noise in 3 DOFs to characterize the OLTF in 3f for DRMI lock: 

• Noise in PRCL(ampl=7.5e3) using "DARM_noise"          20.04.00UTC(+120s)(see fig 5) UGF~50Hz with PM~25 deg
• Noise in SRCL(ampl=5e5) using "PRCL_noise"              20.34.00UTC(+60s)
• Noise in MICH(ampl=3.2e5) using "SRCL_noise"           21.07.00UTC(+120s) (see fig 6)  UGF~7.5Hz with PM~20 deg
• Noise in SRCL(ampl=6e5) using "PRCL_noise"              21.27.00UTC(+120s)(see fig 7) (We might need to remeasure SRCL UGF and PM)

At the end of the shift, we turn off all noises and misaligned PR and SR and locked the arms on IR.