The bake for the RGA on the end door for HAM6 has started, turned on at 16:00 utc.

This morning around 15:45 utc, after checking the health of the ion pump on HAM7 (IP19), its isolation valve was opened.  No issues doing so, pressure in HAM7 is going down, see attached trend plot.

During the Tuesday maintenance reboots, zotvac0 did not shutdown properly, meaning the regular 08:00 did not run. Erik got the machine back and I rescheduled today's fill for 08:20

Tue Aug 13 08:29:17 2024 INFO: Fill completed in 9min 13secs

Gerardo confirmed a good fill curbside.

7min 20sec into the fill (1min 48sec before fill completion) TC-B failed. Its temperature reading went from  -52C to +1372C

The fill completed using TC-A. In the attachment, the TC-B line disappears due to it being an inverted log plot.

TITLE: 08/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Preventative Maintenance
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 14mph Gusts, 9mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.05 μm/s
QUICK SUMMARY: We continue to pump down. Tuesday maintenance day activities planned for today.

This is a sister alog to LLO:72613. After discussion with the calibration group, Joe and I have proposed and pushed a small but important fix to the CAL_LINE_MONITOR_MASTER/COHERENCE block. When the IFOs are down, the coherence for various calibration and monitoring line transfer functions is 0 (this is good). However, the TF uncertainty, which is also produced by the coherence block, was found to be railing at 0 too. How can the uncertainty be 0 if there is no coherence?! It turns out that a coherence of 0 was causing a divide by 0 that, on the front end, presents as ... you guessed it, 0. The new h1calcs models (updated at LLO then synchronized by me to LHO) fix that. 

Now the coherence signal entering the uncertainty-calculation logic will be kept within 1e-6 to 2. We allowed for a coh value above 2 in order to avoid inadvertently 'hiding' egregious errors in the coherence calculation by forcing it to stay below 1. Thinking about this further now that I'm writing this...that wasn't necessary as the coherence channel itself isn't affected by our new changes. oh well.

I've attached an annotated screenshot of Joe's screenshot in LLO:72613 to show the new component we've installed. 

The h1calcs updates should be put in place during tomorrow's maintenance period.

Today's activities:
- After reaching ~1.6E-6 Torr in the Corner (according to BSC3's gauge), GV1 was opened. This immediately brought down the corner pressure to ~9E-7 Torr
- A few hours after this, GV2 was also opened. This quickly brought down the pressure further to ~6.5E-7 Torr
- Opening up of GV1 and GV2 was 2 steps of a strategy, which used the Y and X manifolds as "vacuum accumulators" (the turbo pumps were switched on these volumes for the entire vent, so the pressure in these volumes was very low - ~2-3E-8 Torr). This came with immediate pressure drops, and now there is 6500 l/s pumping speed in the corner instead of the 2500 l/s. This means now a ~15 m^3/h real throughput instead of ~1.5 m^3/h before these actions
- Because of these openings, the pressure in CP2 started to rise slowly, because GV7 was only soft-closed. So, after reaching 3.4E-9 Torr, more pressure was applied to GV7 - it was noticed, that most likely because of the inst. air actions, the pressure there was very low, <5 psi. Now it was set to ~12 psi, and so CP2 pressure stabilized

The pressures currently:
- Corner (at BSC3): 6.1E-7 Torr
- HAM6: 7.4E-7 Torr
- HAM7 + Relay tube: 2.64E-7 Torr

TITLE: 08/12 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
SHIFT SUMMARY:
H1 is in a vacuum pump down state since last week. We are still pumping down.
Current corner station vacuum pressure occording to VAC channel  H0:VAC-LY_Y1_PT120B_PRESS_TORR : 6.25e-07

VAC team decided to open the 2 of the 4 Gate valves today. This allows them to pump down with more vacuum pumps thus increaseing the rate at which the vacuum chamber is evacuated.

19:16 UTC Vacuum pressure high at BSC8, BSC2 and HAM6 This is because Gate Valve 1 was opened by Janos and Gerardo.
21:55 UTC Vacuum team opened Gate valve 2, this opened BSC7 to the rest of the CS.
GV7 was soft closed, I was monitoring H0:VAC-LX_X3_PT134B_PRESS_TORR and saw an increase in pressure.
23:23 UTC Janos put more pressure from the intrument air onto GV7 which stopped the increase in pressure at H0:VAC-LX_X3_PT134B_PRESS_TORR.

LOG:

Closes FAMIS#26469, last checked 79342
 
 HEPI pump trends looking as expected (attachment)

Mon Aug 12 08:08:15 2024 INFO: Fill completed in 8min 12secs

TITLE: 08/12 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 12mph Gusts, 9mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY:
Pump down has continued throuout the weekend undisturbed.
Pump down is expected to continue for the rest of the week.

Current pressure as read by the channel H0:VAC-LY_Y1_PT120B_PRESS_TORR  = 1.67e-06
 

Sun Aug 11 08:08:59 2024 INFO: Fill completed in 8min 55secs

Sat Aug 10 08:08:48 2024 INFO: Fill completed in 8min 44secs

TITLE: 08/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Oli
SHIFT SUMMARY:
2 tours came through the control, but other than that we have just been watching the Vacuum system slowly evacuate the vacuum chamber today.

LOG:

TITLE: 08/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 13mph Gusts, 10mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY:
H1 still pumping down.
There aren't any alerts about Vacuum Pressure High at BSC2 or HAM6
Vac channel : H0:VAC-LY_Y1_PT120B_PRESS_TORR currently reads 3.83e-6 Torr and falling.
 

Fri Aug 09 08:06:56 2024 INFO: Fill completed in 6min 53secs

Today's activities:
- In order to advance further safely, the instrument air system needed to be fixed, at least temporarily, but reliably. Currently the Kobelco compressor is being used as an instrument air compressor, for details, see aLog: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=79512
- The HAM6 turbo was started up with its designated backing cart. This cart needs instrument air, as one if its safety valves is pneumatic. This turbo was running for 2-3 hours before it was valved in, to eliminate any potential risks with the inst. air
- The HAM6 turbo was valved in at ~12:50. The pressure immediately went down in HAM6 by 2E-6 Torr, and in the corner in general by 5E-7 Torr
- The HAM5/HAM6 annulus system pumpdown continued. The Annulus Ion Pumps have been also switched on, and after some struggle they came alive. The pumping carts are still there though, they are at <1E-5 Torr
- As HAM7 caught up with the relay tube, the pumping of the relay tube was stopped, and it was valved together with HAM7 (RV-2 open)
- The rebuilt HAM6 RGA is being pumped, before it will be baked out, starting with next Monday. A pumping cart has been brought from the FCES for this purpose

The pressures currently:
- Corner (at BSC3): 4.3E-6 Torr
- HAM6: 5.8E-6 Torr
- HAM7: 5.9E-7 Torr
- Relay tube: 6.5E-7

TITLE: 08/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: n/a
SHIFT SUMMARY:

Corner station volume continues with pump down.  LVEA cleaning parting in the afternoon.
LOG:

• 1503-1606 Technical cleaning:  LVEA (karen,kim)
  • 1711-1726 H2 Elec room (kim)
• 1601 Pump-down of Corner volume activities continue with trips in/out of lvea and trips to FCES for equipment (travis, janos)
  • 1810-1824 checking OMC ion pump (gerardo, janos)
  • 2015-2230 VAC vendor tours 
  • 2307-2312 travis checking on the pumps
• 1730 Daniel giving tour to visitor with European Space Agency/LISA
• 1820-1940 SUS transfer functions (jeff, oli)
• 1853-1928 Optics lab work (camilla)
• 2025-2300 LVEA Clean-Up work (chris, ericO, betsy, jason, rahul, oli, marc, neil, ibrahim, jonathan, tony, camilla, keita, tyler, et al.)

Transfer functions for SR3 and OM1 in partial vacuum are looking good!

HPI(HAM5&6) - LOCKED and OFFLINE

ISI(HAM5&6) - DAMPED

VAC(HAM5&6) - Currently at 10^-5 Torr

Status of suspension

OPTIC    ALIGNOFFSET    CD STATE

SR3         OFF                     1, LP OFF

OM1       OFF                     Fixed in 2, LP ON

Filepaths

SR3

TFs - $(sustrunk)/HLTS/H1/SR3/SAGM1/Data/2024-08-08_1800_H1SUSSR3_M1_WhiteNoise_*.xml

Analysis - $(sustrunk)/HLTS/H1/SR3/SAGM1/Data/2024-08-08_1800_H1SUSSR3_M1*

Comparison to pre-vent and post-vent in-air - $(sustrunk)/HLTS/Common/Data/allhltss_2024-08-08_H1SUSSR3_M1_Phase4b_unDamped_ALL*_TFs.pdf

OM1

TFs - $(sustrunk)/HTTS/H1/OM1/SAGM1/Data/2024-08-08_1900_H1SUSOM1_M1_WhiteNoise_*.xml

Analysis - $(sustrunk)/HTTS/H1/OM1/SAGM1/Data/2024-08-08_1900_H1SUSOM1*

Comparison to pre-vent and post-vent in-air - $(sustrunk)/HTTS/Common/Data/allhttss_2024-08-08_OM1_H1SUSHTTS_Undamped_ALL*_TFs.pdf
 

J. Kissel

Took the opportunity to grab post-OFI-repair vent, in-vac transfer functions of the following HAM5 and HAM6 SUS. Of course, we're not at full observing-level vacuum, but most of the molecules are out of the chamber that would contribute to buoyancy, so the SUS are at the position they will be in observing-level vacuum.

Executive summary: I'm happy with all SUS that I measured -- including the two that were "interesting" and or touched during this vent -- SRM and OFI.
For the story about SRM, see LHO:79433.
And of course, the OFI had had optics replaced.
Several other SUS in HAM5 / 6 were not touched during the vent (aside from a few alignment sliders), so we didn't expect any degradation in performance and don't see any. These SUS are ready to resume observing gravitational waves!

Processed results will be posted as comments below.

Some relevant details of the status of the suspensions and their surroundings during the measurements.
Environment Status (Same for HAM5 and HAM6)
    ISI DAMPED
    HPI OFFLINE and mechanically locked
    VAC Pressure at 1e-5 Torr
 
Status of alignment offsets and coil driver switchable filter requested (CD) State.
    OPTIC   ON/OFF     Value (if on, [urad])     CD State
    SRM     ON          P/Y : +1663 / -3095      1, LP OFF
    ZM6     OFF         (n/a)                    Fixed in 2, LP ON
    OFI     OFF         (n/a)                    Fixed in 2, LP ON
    OMC     ON          P/Y : +340.5 / 0.0       1, LP OFF
    OM2     ON          P/Y : +716 / -1701       Fixed in 2, LP ON
    OM3     ON          P/Y : -1147 / +20        Fixed in 2, LP ON

File Names:
    SRM         HSTS/H1/SRM/SAGM1/Data/2024-08-08_1823_H1SUSSRM_M1_WhiteNoise*.xml
    ZM6         HXDS/H1/ZM6/SAGM1/Data/2024-08-08_1828_H1SUSZM6_M1_WhiteNoise*.xml
    OFI         OFIS/H1/OFI/SAGM1/Data/2024-08-08_1850_H1SUSOFI_M1_WhiteNoise*.xml
    OMC         OMCS/H1/OMC/SAGM1/Data/2024-08-08_1900_H1SUSOMC_M1_WhiteNoise*.xml
    OM2         HXDS/H1/OM2/SAGM1/Data/2024-08-08_1920_H1SUSOM2_M1_WhiteNoise*.xml
    OM3         HTTS/H1/OM3/SAGM1/Data/2024-08-08_1935_H1SUSOM3_M1_WhiteNoise*.xml