WP11850 Resync Atomic Clock

Daniel, Fil, Dave:

13:32 PDT: Daniel resynchronized the MSR Atomic Clock  to the timing system's 1PPS to clear the timing error.

The procedure was:

Connect a Windows laptop (Daniel's surface) to the RS232 port on the rear of the Symmetricom 4310 Cesium Frequency Standard unit (located in MSR Rack02 U26-27). We used a DB9 null-modem and serial/USB converter cable to connect the RS232 connector to a USB-A port on the laptop.

Daniel ran his monitor code, setting up the serial port for 9600 Baud. We verified the error string as "16,07,00,00,00" which, as before alog70401, means 0x16 Reboot Alert, 0x07 CBT Signal Degradation.

Daniel ran a short 50Ohm coax BNC cable from the SYNC port on the rear of the Atomic Clock to port 8 of the comparitor (the first output 1PPS port). He then ran the resync command which cleared the error.

[Joe B, Louis D, Vlad B]
In an attempt to understand some of the strange low frequency sensing measurements made at LHO, we've been looking at alternative paths between sensing (meters of motion at the mirror) and actuation back on the mirror that might not go through the typical DARM filter bank.

While looking, we found that there is clear line coupling (i.e. lines above a certain height in DARM) to the DHARD_Y (and DHARD_P) ASC input. Interestingly, the PCALY transmitter channel (so the power on the PCAL laser before it bounces off the optic) is clearly seen by the DHARD_Y loop, shown in attached image.  The PCAL is a separate actuator from what the ASC loops use to actuate, and thus knows nothing about angle and length coupling.  One can also see all the other calibration lines also showing up very clearly in DHARD_Y as well.  If there is imperfect diagonalization of the ASC outputs such that they couple back into length, this effectively becomes a parasitic path parallel to DARM.

TITLE: 05/06 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 151Mpc
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 29mph Gusts, 19mph 5min avg 
    Primary useism: 0.08 μm/s
    Secondary useism: 0.15 μm/s
QUICK SUMMARY:

After a lockloss while holding ISC_LOCK at LOWNOISE_ASC to fix the TRANISTION_FROM_ETMX issue, we shifted focus to fixing the PRCL1 issue we were having with DRMI, so we were holding in DRMI for a bit. Once that was fixed we went back to holding in LOWNOISE_ASC. after that Commissioning was started.

• Change PSAMS from 7.5/0.55 to 8.8/-0.67
• Edits to SQZ alignment GRD
• Camilla/Erik troubleshooting ITM charge measurement injections
• Jitter injections
• NB injections
• SRCL FF gain adjustment
• PRCL injections
• HRTS injections?

We were able to get back to NOMINAL_LOW_NOISE at 16:50 UTC and got back into OBSERVING after Commissioners were done with their Commish wish list at 18:36 UTC.
H1 has now been Locked for 3 hours.  
Just unlock....

To get back into Observing, Jenne and Sheila reverted H1:ETMY_L3_LOCK_BIAS_OFFSET (with a 120s ramptime) from -7.5 to it's usual observing value of -3.0.

lscparams.py has been changed from -3.0 to -7.5. Maybe this is the 200V change Robert puts in 77633 but it looks like it's either been 320V or 115V recently, plot attached.

Naoki, Sheila, Camilla.

We edited SQZ_MANAGER.py state SCAN_ALIGNMENT_FDS to now automatically take go to Anti-SQZ (hard-coded value 100 with CLF phase negative sign), tune the asqz angle and then do the 4 degrees of freedom for ZM4/6 alignments.  When it's finished it will take sqz angle back to the original. Total time taken ~5minutes.

It's still best to run SCAN_SQZANG after this has ran to find the best angle for squeezing (another 2 minutes). Then take SQZ_MANAGER to FREQ_DEP_SQZ to go into Observing.

OpsInfo:  If squeezing is bad (see notes in wiki) and you have Jenne's permission, you can now optimize SQZ alignment by taking SQZ_MANGER to SCAN_ALIGNMENT_FDS, then SCAN_SQZANG before back to FREQ_DEP_SQZ. Total time ~8 minutes. SQZ Wiki updated.

Naoki, Camilla

Since we think that 8.8/-0.67 of ZM4/5 PSAMS is better than 7.5/0.6 as reported in 77268, we changed PSAMS from 7.5/0.6 to 8.8/-0.67 and ran SCAN_ALIGNMENT twice. It seems that the squeezing is more flat with 8.8/-0.67 and is similar to the reference in NUC33.

There was again coherence between DARM and SRCL in last night's lock, so I ran a SRCL injection and adjusted the gain of the FF. (FF attached)

I changed the gain from 1.15 to 1.12.  77570 and 77492 are other times this gain has been adjusted in the last few weeks.

The coherence of SRCL to DARM is low at the frequencies that we care most about for this injection (20-50Hz), but the noise in DARM is well above the ambient DARM noise.

Attaching SDF screenshot for both the SRCL and PRCL changes here.

Edit: the SRCL excitation was on from 18:18:57-18:22:00 UTC May 6 2024. 

FAMIS 20027

PMC reflected power continues to rise, as seen in recent weeks. The more rapid increase starting about 3 days ago looks to correspond to a drop in ISS diffracted power percentage; I'll adjust the ISS RefSignal at next opportunity to bring that back to the desired 2.0-2.5% zone.

Sheila, Camilla.

After this morning's windy lockloss from TRANSISITON _FROM_ETMX, we continued previous 77366 troubleshooting.

Sheila manually stepped though TRANSISITON _FROM_ETMX:

• We found that only the L1 history was cleared, giving unwanted outputs when we turned on L2 and L1 gains.
  • Sheila added a line to clear L2 history (line 5115: ezca['SUS-ETMX_L2_LOCK_L_RSET']=2).
• We then lost lock when turning off two DARM1 filters  (ezca.switch('LSC-DARM1', 'FM1', 'FM2', 'OFF')). This seems the cause of our glitch, attached shows this DARM1_SWSTAT change at the same time as the glitch on a successful lock.
  • FM1 "8^2:2^2" has a 20dB gain at low frequency and 10s ramp, but FM2 "MadHatter" has a 40dB gain and 0.09s ramp so is probably to blame.
  • Sheila notes that "MadHatter" used to be left on during the transition (74798, 75451). To check this, I see that FM2 was kept on though a successful transition from 75631, plot attached.
  • Sheila edited ISC_LOCK to leave DARM1 FM2 on during TRANSISITON _FROM_ETMX but turn it off during the next state:  LOWNOISE_ESD_ETMX, once we are already on NewDarm and effect of this low frequency filter is suppressed.
• After these changes, our locking was successful with no glitches: plot attached.

Anamaria, Sheila, Robert

We scanned the biases for three test masses to find the coupling minimum for currents that we injected onto the building ground. The optimal ETMY bias was 115 V in January of 2023, 170 V in Aug. (72308) and 200 V now.  With ITMX at 0V, the optimal for ITMY was 60 V in March of 2023 (68053) and -222 V now, The figure shows some of the bias scans.

Anamaria, Robert

We photographed, from a second angle, the beamspot of a stray beam that I noticed last visit (76969 - Fig. 3 ). The photos (Figure 1) confirm that there is indeed a bright stray beam hitting, at a grazing angle, the bellows and other parts of the spool piece between HAM3 and the IMC tube.

I also wanted to measure the power of the stray beam that had been producing a large 48 Hz peak in DARM during early O3, in order to improve my scattering coupling calculations. This is the beam that reflects off of the PR2 scraper baffle and hits the illuminator viewport on HAM3, which we mitigated by inserting a black-glass viewport cover (52184). We were surprised by how bright the beam is, reaching 20 mW on the power meter (see Figure 2), even though we could not fit the whole beam on the meter. We estimate that the beam may reach 60  mW.

Finally, we made movies as we swept the ITMY compensation plate, hoping to see some indication of where the ghost beams are hitting, but did not. We will have to wait until Alena gives us the likely position of the CP ghost beams based on the angles that Anamaria showed us how to measure.