We started at 14:00 UTC and to not interfere with the ITF and risk to unlock, we manually injected the SQZ. 

• System initial status: ITF LOW NOISE 3; SQZ_MAIN @SQZ_Locked_NO_FC

• 14:28:26 AA loop engaged

We performed a first CC phase scan (Fig. 1-2): 

• 14:39 CC scan started DCP = 195 Hz

• 15:02:21 CC scan ended (fast shutter closed), ITF in shot

• 15:26:15 fast shutter opened

• 15:36:22 ITF in SQZ phi0 = 0.65 rad

• 15:39:19 SQB1 TX angle set to 300 (initially at 310)

• 16:42:58 SQB1 X position set to -3200 (original position)

• 16:47:58 ITF in SQZ

After the first CC scan we realized the magnitude was similar to the last shift (entry #64094) even though there should be a higher level of injected SQZ. We decided to try to improve the magnitude by acting on SQB1_TX and SQB1_X DOFs. We worked on this from 15:39:19 to 16:42:58 UTC. Finally we left SQB1_X as it was and we changed the set point of SQB1_TX from 310 to 330 urad. The fluctuations on the magnitude are reduced (Fig. 3).

We then performed another phase scan (Fig. 4-5)

• 17:05 CC scan started DCP = 195 Hz

• 17:28 CC scan ended (fast shutter closed), ITF in shot

After the second CC scan we realized the SQZ angle is actually around 1.05 rad, so we decided to repeat the SQZ mode acquisition.

• 17:39:53 fast shutter opened, ITF in SQZ phi0 = 1.05 rad

• 17:49:08 CC loop engaged, gain=75000 (glitch between 17:54:50 and 17:56:14)

• 17:58:54 ITF in ASQZ phi0 = 2.75 rad

We were able to get another CC phase scan with DCP setpoint at 225 Hz (Fig. 6-7). Fig. 8 reports also the shot SQZ and ASQZ acquisitions made after the scan.

• 18:11 DCP value set to 225 Hz

• 18:44:11 ITF in shot

• 18:46: CC scan started DCP = 225 Hz

• 19:09 CC scan ended

• 19:15:07 ITF in ASQZ phi0 = 2.7 rad

• 19:22:48 ITF in SQZ phi0 = 0.95 rad

• 19:28 DCP value set back to 195 Hz

SHIFT GOAL:

The goal was to perform several CC scan at different SR angle. Nevertheless, due the not optimum condition of the MZ and OPA (waiting for the retuning) we decid to perform a couple of scan without changing the SR angle to check the SQZ alignment-

SHIFT activity:

We started at  16:00 UTC and to not interfere with the ITF and risk to unlock, we manually injected the SQZ. 

• System initial status: ITF LOW NOISE 3; SQZ_MAIN @SQZ_Locked_NO_FC

• 16:10:39 EQB1  fast shutter opened (process: SQZ_ctrl/shutter ‘open’)

After that the CC_loop was engaged and then  the AA (process: SQZ_PLL_AA/ Matrix and Filter ‘AA dither enable’).

• started a CC 4MHz phase scan @ 16:52. 

  • time per point = 6 s

  • - initial phase  = 20 degree

  • - final phase = 230 degree

  • - phase steps = 1 degree

  • - random phase = False

  • - Closed shutter sleep time = 120 s

  • - AA closed on dither = False

  • - cc loop gain   = 75000.0

N.B: No glitch during the scan, it was just before and after (see plot)

In meantime Henning checked the MZ and changed lowered again the offset at 0.035 V due to the humidity  misalignment that spoiled the contrast and induced the set point near the actuator saturation. After the Henning action we redid the scan. 

We stopped at 19.25 after that some data have been collected at the CC phase value corresponding to the SQZ and ASQZ, or better to the minimum and maximum values in the BRMS range @210 MHz and in other ranges.

Further data  and plot in the following comments.