Dew point measurement taken this morning by Jordan, read at -43.9 ^oC.  Some demand by HAM5/6, small crew at work.

TITLE: 07/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: None
SHIFT SUMMARY: The OFI team was able to get the AUX laser aligned and verified that the SQZ beam can get to OM1. Tomorrow morning first thing we will be transitioning the LVEA to laser safe and continuing the OFI work by taking the KTP out and taking the HAM6 -X door off.
LOG:

- Continuing work on aligning AUX laser

- Aligning sqz beam

- Getting ready to transition to laser safe

Keita, Jennie W

Keita and I worked out the distance behind SRM we have to place the AUX launcher to match the beam radius the IFO beam normally has on SRM on its way into the OFI.

This is based on measurements of beam profile Keita made in the optics lab with the aux laser mounted with a collimator on it.

The code used to do this is saved in ligo/home/jennifer.wright/ModeMatching/beam_diverg.py

The graph attached shows the measured points in orange and the fitted points in blue.

FAMIS 21009

The stabilization trends are especially interesting this week; PMC reflected power is steadily increasing while transmitted power (along with RefCav transmission and ISS diffracted power) is decreasing. This is particularly interesting as we thought this behavior might disappear when we swapped in the new PMC.

Sam and I have been investigating a ~40 Hz peak in the HAM ISIs and PEM accelerometers, first noticed by Camilla and Sheila in alogs 79001 and 78879. Jim also investigated and suggested the peak may be caused by gain peaking from the isolation loops (alog 79145). The peak is strongest in HAMs 2, 6, and the LVEAFLOOR YCRYO Z accelerometer. We tracked the first appearance of the peak to May 20th. We've found there are actually two peaks roughly 0.2 Hz apart, which drift a bit in frequency from ~39.45 Hz (20/05/24 16:00 UTC) to ~40.2 Hz (20/05/24 22:00 UTC), measured from the point between the two peaks (see 1st attachment). The peaks consistently remain about 0.2 Hz apart in frequency but they do not always have the same magnitude ratio, even between channels measured at the same time (see 2nd attachment). Overall, the peaks vary in magnitude, occasionally disappearing altogether, but we have yet to find a time when one peak disappears and the other doesn't (see 3rd & 4th attachments for peaks disappearing and reappearing, respectively). We'll continue looking into surrounding peaks and the coherence with DARM.

16:09 Tue 23 July 2024 PDT the atomic clock jumped to +0.42S out from the Timing system.

This is the third time this has happened in the past month. Prior to that it had only happened once in the past year, on 4th May. Here is a table of the atomic clock out-of-syncs for the past year

I have extended the timing comparator's tolerance to 0.9999999 seconds to 'green up' the corner station timing.

Wed Jul 24 08:05:48 2024 INFO: Fill completed in 5min 44secs

Jordan confirmed a good fill curbside.

TITLE: 07/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 4mph Gusts, 2mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.05 μm/s
QUICK SUMMARY:

Close to getting the AUX laser aligned (79291)!

TITLE: 07/23 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: None
SHIFT SUMMARY: Work today was just a continuation of work on aligning the AUX laser
LOG:                                                                                                                                                                                                                                                                                                          

Site wide power glitch at 13:43:30 PDT (20:43:30 UTC) Tue 23rd July 2024. Lights in corner station flickered. Both end station HEPI Pump Controller VFDs tripped.

Jim untripped the EX VFD, but the HEPI pump controller does not seem to have control. Jim and Patrick are investigating.

Dew point measurement done this morning, read at -43.4 ^oC.  There was some demand already on the system from HAM5, since both soft covers were off.  No demand from HAM6 or HAM7.  Flow was opened later to HAM6, since more personnel started working in-chamber.  HAM7 remains valved out.

Genevieve and Sam asked about HAM1 and HAM2 motion around 40 hz. I hadn't look in detail in this frequency band for a while, this is typically higher frequency than we are worried about with ISI motion. But it turns out HAM2 is moving a lot more than HAM3 generally over 25-55hz, and particularly around 39hz. It looks like it might be due to gain peaking from the isolation loops, but could also be from something bad in the HEPI to ISI feedforward. The extra motion is so broad I don't think it's just one loop has a little too much gain, so I'm not sure what is going on here. 

First image are spectra comparing the motion of the HEPIs for those chambers (HAM2 HEPI is red and HAM3 is blue) and the ISIs (HAM2 ISI is green, HAM3 is brown). The HEPI motion is pretty similar, so I don't think it's a difference in input motion. HAM2 is moving something like 10x as much as HAM3 over 25-55hz. The sharp peak at 39 hz looks like gain peaking, but I'm not sure that explains all the difference.

Second plot shows the transfer functions from HEPI to ISI for each chamber. Red is HAM2, blue is HAM3. The 25-55hz tf for HAM3  is not very clean probably because HAM3 is well isolated. HAM2 tf is pretty clean, it makes me wonder if maybe something is messed up with feedforward on that chamber. Maybe that is something I could (carefully) fix while other troubleshooting for the detector is going on.