J. Oberling, R. Short, J. Driggers

Summary

I'll get a more detailed alog in tomorrow, right now I am exhausted so a summary it is.

We swaped our in-service PMC, SN 007, with our spare, SN 004, to correct what appeared to be a very slow build up of loss in the PMC (time scale of several months).  The swap itself went well with no issues (some very slight yaw alignment required to lock the new PMC), but we ran into a problem upon PMC recovery.  The new PMC was presenting the exact same issue as the old PMC, in that we were measuring a high visibility but a markedly lower power throughput.  We could find no cause for this: control loop looked fine, PMC optics were clean (had 1 optic that had to be cleaned pre-install, but all looked great afterwards), our locked voltage on the locking PD was well above the PD's dark voltage.  After much investigation and deliberation, we decided to continue recovering the new PMC so we could get the IFO back up and running.  We carefully upped the power incident on the PMC in stages until we had reached full power (measured with our water cooled power meter at 128.1 W).  At this point we were measuring a visibility of 89.6% and a power throughput of only 82% (105.1 W transmitted with the ISS OFF).  Our locking PD locked voltage is roughly -0.061 V and its unlocked voltage is roughly -0.453 V; the dark voltage on this PD is -0.015 V.  The UGF is ~1.1 kHz with a phase margin of ~53.9 deg.

We then found we could not lock the FSS RefCav, and upon inspecting that path found the alignment to be off.  So the PMC's mounting scheme did not exactly maintain the post-PMC alignment.  Already being almost 3 hours past the end of maintenance we did a quick recovery of the FSS while Jenne and Sheila worked to recover the IMC and the beam alignment on ISCT1 (since the post-PMC alignment shifted slightly this changed the beam alignment into the IMC and on ISCT1, which are both many meters downstream of the PMC).  The FSS will have to be tuned up next week, as we were only able to get a RefCav TPD of just over 0.7 V.  We forgot to check the ALS/SQZ pickoff before leaving the enclosure, but found it was reading too low once we were out; as a quick fix Sheila lowered the thresholds for locking both ALS and SQZ, and I will go back into the enclosure in the morning to correct the beam alignment into the pickoff.

There is still optimization to do on this new PMC, but it's up and running for now.  We will watch the PMC Refl signal over the next week to see if it exhibits the same behavior; if it does then the problem likely lies elsewhere, we'll see what happens over the next week.  Regardless, we will have to go into the enclosure next week to do some PMC optimization, re-tune the FSS path, and see if we can figure out what the root issue here is.  More to come (including a more detailed alog of today's work).

TITLE: 07/02 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 9mph Gusts, 5mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY:

• We're still relocking following maintenance
  • Running an initial alignment currently

DriptaB, FranciscoL

After one week of having the inner beam up on the Rx sensor (alog 78807), on July 2, we moved the beam from up to center.

The last page of EndStationLog.pdf lists the voltage values after each significant step of procedure T2400163. The steps represent writing down a voltage value after a particular change to the beam position. Some highlights from the recorded values:

• ("moved beam") Finalized beam movement of inner beam. See InnerBeamAfter.jpg. Target still on Rx PS. Fine adjustments to yaw had to be done to maximize the signal.
• ("Target off") Recorded the voltage from the Rx sensor with the inner beam only and with the target removed from Rx PS. Readout of FLUKE voltmeter of 1.684V is higher by 6 HOPs to previous position (1.683V).
• ("Both beams") The measurement was recorded after removing beam block on outer beam and removing the target. See BothBeamsAfter.jpg. The measurement of 3.382V is *equal* to the initial measurement (3.382V).

The 'Initial' measurement is *equal* to the last voltage measurement from the previous movement, done on June 25 (alog 78807). The initial and final voltage measurement during today procedure did not change.

RickS, FranciscoL

After one week of having the inner beam centered on the Rx sensor (alog 78514), on June 25, we moved the beam from center to up.

The last page of EndStationLog.pdf shows a diagram of the movements that have been done and, on dashed lines, the move that were left to do. The previous to last page on file lists the voltage values after each significant step of procedure T2400163. The steps represent writing down a voltage value after a particular change to the beam position. Some highlights from the recorded values.

• ("Outer beam blocked, no target") Only inner beam at Rx detector. A change of 1 mv on the hanheld FLUKE voltmeter corresponds to ~ 7 HOPs. May bring keithleys DVM for upcoming measurements.
• ("Target off") Finalized beam movement and recorded the voltage from the Rx sensor with the inner beam only. See InnerBeamAfter.jpeg. Voltage of 1.683V is *equal* to previous position (1.683V). Fine adjustments to pitch and yaw did not improve the amplitude of the signal.
• ("Both beams") The measurement was recorded after removing beam block on outer beam and removing the target. See BothBeamsAfter.jpeg. The measurement of 3.383V is lower by 0.03% from initial measurement (3.384V).

The 'Initial' measurement changed by 11% from the last voltage measurement from the previous movement, done on June 18 (alog 78514). The initial and final voltage measurement during today procedure changed by 0.03%.

(Isaiah V., Gerardo M.)

Functionality test for the corner station turbo pumps, see notes below:

Output mode cleaner tube turbo station;
Scroll pump hours: 5908.3
Turbo pump hours: 5970
Crash bearing life is at 100%

X beam manifold turbo station;
Scroll pump hours: 1950.8
Turbo pump hours: 1955
Crash bearing life is at 100%

Y beam manifold turbo station;
Scroll pump hours: 2283.6
Turbo pump hours: 956
Crash bearing life is at 100%

Note for the output mode cleaner tube system, the scroll pump is making a little of extra noise when active, noise comes and it goes, the scroll pump did not made that noise during last FAMIS task.

FAMIS tasks 23532, 23604 and 23652.

TonyS, FranciscoL, [Remote: RickS]

After one week of having the inner beam left by 5mm on the Rx sensor (alog 78373), on June 18, we moved the beam from left to center.

It is very important to note that this procedure had a different order than the movements done previously. The purpose of the procedure - move the inner beam 5 mm to investigate sources of systematic uncertainties on the pcal system - is not affected by this change. The intention of changing the steps of the procedure is to see more clearly any unexpected changes introduced by moving the beam, especially in the optical efficiency.

For the previous movements, the target would always remain in the Rx_PS. During this procedure, the outer beam is blocked before placing the target.

AlignedTarget.jpg shows the alignment with the beam height gauge. The file EndStationLog.pdf lists the voltage values after each significant step of procedure T2400163. The steps represent writing down a voltage value after a particular change to the beam position. Some highlights from the recorded values.

• ("Inner beam, no target") Only inner beam at Rx detector. See InnerBeamBefore.jpg - note, the beam height gauge was removed before moving the beam.
• ("Inner b. no target") Finalized beam movement and recorded the voltage from the Rx sensor with the inner beam only. See InnerBeamAfter2.jpg. Voltage of 1.684V is 0.12% from previous position (1.682V). There are discussions to make a calibration measurement at each position of the inner beam as a continuation of this series of measurements. Also should track the optical efficiency given by PCALX_FORCE_COEFF_OPT_EFF_LIVE_OVER_REF
• ("Botb. no targ.") Both beams, no target. The measurement was recorded after removing beam block on outer beam and removing the target. The measurement of 3.388V is higher by 0.17% from initial measurement (3.382V).

The 'Initial' measurement is *equal* to the last voltage measurement from the previous movement, done on June 11 (alog 78373). The initial and final voltage measurement during today procedure changed by 0.17%.

Camilla, Sheila

We looked at some signals related to the ALS X beatnote, relating to the problems described in 78703 and 78691. 

This morning the PSL is down so there is no light coming out of the X end or Y end fiber.  For the Y arm, the beatnote PD gets about 0.2mW from the fiber; the X arm beatnote PD doesn't show a noticable step down when the PSL went offline, indicating that there is much less light coming from the fiber reaching the X beatnote PD than the Y.   This has been the case at least since last Novemeber, when the PLL seemed to be working fine. 

The total power on the two beatnote PDs are similar, both just over 2mW. When we aren't having these temperature dependent changes in the X beatnote, the two beatnotes have similar sizes according to H1:ALS-X_FIBR_A_DEMOD_RFMON.  As long as the amplification at the two end stations are the same, this means that the beatnote alignment and mode matching at end X must be better than at EY, to get the same beatnote strength with much less light from the PSL.

Without light from the PSL, the ALS X beatnote noise floor is -32dBm, ALS Y beatnote noise floor is -41dBm.  This means that when TJ saw an X beatnote of of around -30dBm, 78745 , there was effectively no beatnote.  Camilla and I toggled the noise eater for both lasers, shown in the third attachment here.  The X laser has a larger increase in noise than the Y laser, but both beatnotes returned to their previous values after we turned the noise eaters back on.

The last attachment shows a trend of the beatnote strengths over the last few weeks.  Although the problem had come and gone a few times in the past, it doens't seem to be resolving itself now.

Closes WP 11957.

Gerardo M., Patrick T.

From the WP:
Update and restart the PLC code on h0vacmr to repurpose the voltage and torr channels from the IP 8 gamma ion pump controller for the readout of a MKS 937 gauge controller. The channel names will remain the same, but the value of the pressure in torr will use a different calibration. This will take the MR CDS vacuum system down for the duration of the work. No DAQ restart should be needed.

This has been completed. The channel reading the MKS 937 is H0:VAC-MR_IP8_VI168_PRESS_TORR. There were a couple of issues generating the TwinCAT 3 solution from the updated powershell script. The first was an error that I did not completely catch, but did not repeat itself on subsequent runs. Twice when I ran it I got a message that the computer was low on memory, and I restarted the computer each time in response. Everything appears to be running now. The code is using git commit b977513795e0827c974ebab238a1cef219ad9840.

Follow up to the previous SRM M1 boost test, I tested the new boost yesterday, druing commissioning with the IFO in NLN. Seems like it works pretty good, I have added it to the ISC_DRMI guardian. Attached asds were taken yesterday, the refs are with the boost on, the live traces are with the boost off. Top plot are SRCL and SRM M3 drives, they are both reduced up to almost 10x around 50mhz, with very little gain peaking around .25 hz. I think the extra high frequency SRCL noise is from a measurement RobertS was doing. Bottom plot are the OAF SRCL length using the ISI gs13 suspoint motions, showing the table motions were very similar between the two measurements.  Hopefully this will help with staying locked during earthquakes and other low frequency motion.

Tue Jul 02 10:09:09 2024 INFO: Fill completed in 9min 6secs

Gerardo confirmed a good fill curbside.

WP 11948

Symmetra batteries on the MSR UPS unit were replaced. All batteries installed are now the V66 version. The 16 batteries on bank 1 were replaced today. Bank 2 batteries were replaced on 2022. Verified unit showed all 32 batteries installed across both banks. Dave confirmed emails were being sent out from unit.

D. Barker, F. Clara. M. Pirello, R. McCarthy

WP 11942
alog 78641

The spare Laser Locking Beat Note Chassis installed on SQTZ0 was removed. Unit was swapped last week but left on the table, alog 78641. Part of ongoing search for glitches seen by SQZ.

Chassis S2300259 stored in EE lab as spare.

F. Clara, M. Pirello

Looked at the wind fences this morning. No new damage. EY has a yoke (from an old repair) that broke a couple months back on the one panel we didn't replace, first attached image. This hasn't gotten any worse. EX still looks okay, second image.

Last week I did a major rewite of the CDS HW reporting EPICS IOC to catch any future DAC FIFO errors which are currently not being shown in the models' STATE_WORD. Part of that rewrite was to obtain all the front end data from the running DAQ configuration hash.

Today I released a new version which:

• Shows the DAQ hash (truncated to last 8 chars) and time it was read
• Checks hourly if the running hash has changed, and if so, rereads the front end data
• Added an EX Timing check to verify the "X" timing error continues to be just the new firmware running on h1susex's timing card

cds_status_ioc.py

WP11955

We installed 8 additional channels to the LD32 DAC for testing in SUS-EX.  While there we cleaned up cable routing for this test, also we swaped the 8x BNC to DB25 adapter to troubleshoot the disconnect on channel 5.

The initial install is located here ALOG78642

M. Pirello, F. Clara

TITLE: 07/02 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 6mph Gusts, 4mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY:
As I was arriving the IFO was just getting back into Nominial_Low_Noise at 14:26 UTC>
Took Observatory mode to Calibration to the Inlock charge measurements.

Everything seems to be currently functioning just fine.


 

Sheila, Jennie W

We lost some range with the hot OM2 so we thought to see if we could move SRM and raise the coupled cavity pole to regain this range as we did before in this entry.

Took 5 minutes no squeeze time.

Opened POP beam diverter to monitor POPAIR

Following the procedure in this entry we opened the SRC1 ASC loops by turning off input and offsets simultaneously after changing ramp to 0.1s.

Set the ramp to 10s, turn gain to 0, clear history, gain back to 4.

Then we started to move SRM alignment sliders.

The starting alignment sliders are here.

started yaw steps down on SRM, wrong way as f_cc avg went down, changed to up in  yaw, then noticed POPAIR_RF18 was going down so switched to pitch steps down. Found a poitn at which it no longer chnaged fcc, went back to maximum found for f_cc. The trends can be seen here where the first vertical cursor is when we opened the beam diverter and the second is when we thought we had the highest coupled cavity pole (middle bottom trace). So we put the SRM sliders to their values for this time after finishing.

I then changed offsets in SRC1 ASC to -0.0417 for ASC-SRC1_P_OFFSET and 0.0977 for ASC-SRC1_Y_OFFSET but didn't turn them on while we grabbed 5 minutes no squeeze time.

17:05:30 UTC closed loops and switched on new offsets.

Sheila used the second period of no squeeze time to plot the how the range compares to June 24th when we had a cold OM2. This plot shows the DARM comparison on the top plot (Yellow is cold OM2, blue is hot OM2) and the range difference on the bottom. This plot shows the cumulative range comparison on the top (yellow is cold OM2, blue is hot OM2) with the same difference in range plotted on the bottom. From the bottom plot it looks like with hot OM2 we gain range between 25 and 40Hz, don't gain between 40 and 90 Hz and lose range for hot OM2 above this point.

So summary is, we didn't completely recover the range by raising the coupled cavity pole. Hot OM2 is good for low frequency range but not for high frequency. We still need to do some PSAMS tuning today so this might regain us range at higher frequencies.

A few weeks back Oli put in an alog about IMC and SRM M3 saturations during earthquake lock losses. In April of 2023 Gabriele had redesigned the M1-M3 offload, reducing the gain of the offload somewhat to get rid of 3-ish hz instabilities in the corner cavities. This may have contributed to the SRM saturations that Oli found, so we want to try adding some low frequency gain back into the SRM offloading.

Sheila wrote out the math for me for the stability of both the SRCL loop and the stability of the M1-M3 crossover, so I have been looking at ways to increase the low frequency gain without affecting the stability above 1hz. The open look gain for SRCL looks like :

SRCL_OLG =  SRCL_sens * SRCL_FIlter * (SRM_M3_PLANT+SRM_M1_LOCK_FILTER * SRM_M1_PLANT);

The SRM M1-M3 offloading looks like:

SRM_OFFLOAD_OLG = SRM_M1_LOCK_FILTER * SRM_M1_PLANT * SRCL_sens * SRCL_Filter / (1-SRM_M3_PLANT * SRCL_sens * SRCL_FILTER);

Both of these are (or behave like) open loop gains (g), so the suppression/gain peaking can be show by looking at the 1/(1-g) for each.

I made a 50mhz boost filter for this and tried it during the commissioning window this morning. Bode plots for the boost (red), boost *m1 lock filters(blue) and the nominal M1 lock filter(green) are shown in the first image).  The affect on M3 drives and SRCL are shown in the second image asds, live traces are with the new boost, refs are without. There is good reduction below 100mhz, but there is gain peaking from the M1-M3 offloading at .2-.4hz. which might bleed into the secondary microseism during the winter. I'm working on a filter with similar gain, but less gain peaking in a region that won't affect the overall rms of the m3 drive as much. I will try installing and testing during maintenance tomorrow.