The replacement turbine flow sensor seems to be working okay and without any leaks.

Whilst the laser was down, the dark voltage of the pre-modecleaner locking photodiode
and frequency stabilisation reflection photodiode was measured.
  PMC locking photodiode : 23.5 - 23.7 mV
       FSS RF photodiode : -4.6 - -4.7 mV

    Whilst engaging the PMC, the output of the locking photodiode would saturate and latch
at random intervals, causing the PMC to oscillate.  This photodiode was replaced with a
spare.
  old : S1107847
  new : S1107848
The measured maximum power that could fall incident on the locking photodiode was ~63 mW.
These occurred at ~83 degrees and 265 degrees.  The minimum power was ~1 mW, and this
occurred at 167 degrees and 347 degrees.

    After locking the FSS, ~10.1 mW was measured after the Faraday isolator located behind
the reference cavity.  This was increased to ~30 mW by rotating WP4 from 98 degrees to 86
degrees.

    Had problems with the stability of the power stabilisation.  The free-running power
fluctuations transmitted by the PMC were perhaps at most 3%.  Yet when the power stabilisation
servo was engaged, it was working far harder than this figure would suggest.  Not obvious why.
Perhaps it's a scattered light issue?





Jason, Peter

All time in UTC:

23:23 Kyle to EY VEA to write down some serial number.

23:26 Peter and Jason out.

23:46 Jenne and Ross to ISCT6

            Kyle's back

01:49 Noticed H0:FMC-EY_CY_H2O_PUMPSTAT alarm went off. Shortly after got an alarm for high temperature at EY. I called John. Timeseires of this channel around the time it went bad is attached below. The chiller went down at 1:13 UTC and back at 01:52 UTC when John turned the pump back on.

02:10 Ran the random walk script on PSL rotation stage so I can calibrate the calculated power and angle for Stefan.

02:26 Realized that I should have called and check with Jason. Turns out there's a beam dump on IOT2L that can only handle low power according to Cheryl's alog. The full power will go to the table if the IMC is unlocked. I stopped the script right away and asked for the RS to go to minimum power.

03:45 We deciede to call it a night. ALS guardian is complaining about communication issue and beat note strength. ISS is still acting up. IMC is left locked and power into the IMC is 1.9 W.

            In CDS land: H1:DAQ-FW1_UPTIME_SECONDS went white, came back for a while and went white again. I tried call Dave but no one answered.

            H1:VAC_MX_X1_PT_343B_PRESS_TORR alarm went off a couple times.

I also tried to fit the few data points I got from PSL rotation stage random walk script. I've attached a screenshot (second attachment). Parameter A and D seems to be hard coded and couldn't be overwrite on the medm screen (and caput) so nothing's changed.

The MX vacuum controls system was upgraded to Beckhoff this morning. I reconfigured the DAQ by:

• renaming the current minute trend files on h1tw1
• installed the new H0EDCU_VE.ini and H0EDCU_FMCS.ini files
• restarted the DAQ at noon PDT Tuesday

I forgot to check if h1fw1 came back after the restart. It had not done so, but h1fw0 has ran with no restarts. I have just remotely restarted h1fw1.

Still to do: rename all the archived minute trend files on h1tw1

Peter, Keita, Stefan

The ISS is still acting up, so we tried to do some diagnostics.

First we had to adjust H1:PSL-ISS_REFSIGNAL to -1.78V to avoid running out of actuation  range. (The diffracted power RMS still seems bigger than before the upgrade - we now fluctuate between ~8% and ~23%). We also had to increrase the ISS gain to 9dB.

The ISS now initially seemed stable. But we were sitting at 22W into the IMC. Of course, that rotation stage is after the IMC. But nevertheless we noticed that when we reduced the selected power an oscillation appeared in the ISS, that sometimes manages to break the loop.

The attached plot shows the two ISS PDs with 3 traces each:

- Now with an oscillation at 2.5kHz

- Now, with no oscillation

- Before the laser upgrade (and with only the first loop closed)

Additionally, the out-of-loop diode (PDA in plot), sees a significant excess in sensing noise below 100Hz. And there are new peaks at ~950Hz and ~4.2kHz.

We are not really sure what couses all this, but one suspicion is scattered light from the high power beam dumps. Excess scatter noise could explain the difference between in and out-of-loop. Also, the abount of scattered light would likely be reduced when less power is dumped. We do not yet understand the 2.5kHz oscillation, which also seems to be moving around somewhat.

The vacuum controls at mid X were replaced with Beckhoff controls and the LLCV at end X and end Y were replaced with electric valves.

The PID control for these are not behaving, so I have set them all to manual at the following percent open:

CP5 60%
CP6 30%
CP7 50%
CP8 40%

The pump levels for CP6, CP7 and CP8 are at or above 100%. The pump level for CP5 is around 90%.

[Jenne, Ross]

Using ITMX from a green-flashing alignment, and BS confirmed with Michelson fringes with the ITMY from a green-Y flashing arm, we've aligned the beam onto AS Air camera, as well as AS_A and AS_B.  Nutsinee is going to start an intitial alignment!

I've expanded the IOT2L power budget from the one I posted in alog 26390 to include all components in the beam path and maximum power levels (saturation/damage) for critical components.

I've attached summary of the IMC REFL unlocked power budget that includes only the O1 (22W), proposed O2 (50W), and future (200W) power levels.

Two components are highlighted in yellow in the proposed O2 columns:

• the p-pol beam is currently being dumped on a razor blade dump, and at 50W will see about 1.2W incident power, which exceeds the typical power range for that beam dump
  • the original plan was to pick off this beam and send it to a high power beam dump
• the RFPD, that will see 61mW at 50W IMC power, which is double the 27mW power level it saw in O1 at 22W
  • I've included a chart that shows how the HWP could be rotated to reduce the power on RFPD to O1 levels

The full documentation is uploaded to T1600107-v1.

TITLE: 04/19 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Nutsinee
SHIFT SUMMARY:
LOG:

• 14:10 - Chris S to X arm beam sealing at quarter mark.
• 14:45 - Jeff B to diode room to install dust monitors.
• 15:10 - Peter to PSL enclosure.
• 15:13 - Christina, Karen to EX, EY cleaning.
• 15:22 - Hugh to outbuildings for general HEPI checks.
• 15:34 - Joe to LVEA to check batteries.
• 15:37 - Kyle to LVEA removing pumbing from turbo on HAM6.
• 15:58 - Richard, Fil to MX to install vac lines.
• 16:04 - Norco Delivery.
• 16:13 - Jason in to join Peter.
• 16:34 - Joe out.
• 16:37 - Cintas at gate.
• 16:46 - John, Chandra to EX and EY to check on actuators on CP7 and CP8.
• 16:48 - Chirstina, Karen going from EX to EY.
• 17:00 - TJ starting charge measurements.
• 17:44 - Kyle out.
• 17:46 - Christina, Karen leaving EY.
• 18:04 - Joe to mids and ends to restock first aid.
• 18:05 - Ed M to LVEA for a measurement.
• 18:10 - Jeff B to LVEA to remove old dust mon equipment.
• 18:12 - Kyle to LVEA to get more numbers.
• 18:19 - Ed M out.
• 18:40 - Kyle out.
• 18:53 - Jason, Peter out for lunch.
• 19:11 - Joe back.
• 19:53 - Jeff B opening up roll up door.
• 20:15 - Gerardo, Patrick to MX.
• 20:19 - Chandra, John to EX then EY to work on the actuators previously mentioned.
• 20:20 - Peter, Jason back into PSL enclosure.
• 20:17 - Kyle to EX then EY to grab a few part numbers in VEAs.
• 20:27 - Jeff B to Ends for dust flow check.
• 20:35 - Joe into LVEA battery check.
• 20:50 - Gerardo, Patrick back.
• 20:51 - Keita, Ed M to LVEA to recenter ITM OpLevs.
• 20:53 - Joe out.
• 21:02 - Bubba, Chris LVEA craning.
• 21:05 - Jeff B to diode room.
• 21:42 - Richard, Fil to EX for CP8 actuators.
• 22:16 - Jeff B out. Done for the day.
• 22:31 - Bubba, Chris out.

Cleared the counts on the listed chambers and counts.

HAM2 - 71

HAM3 - 63

HAM5 - 1205

   Installed the new GT521S dust monitor in Diode room. Ran new vacuum tubing into DR for the new monitor and configured it for operations. Edited the SITEMAP to point to the new monitor code. Working on sorting out the network connection. 

   Shutdown the old vacuum pump and removed old vacuum tubing from the Diode room and the CER. 

Note: This is the last of the new GT521S dust monitors to be installed. Still have a couple of network connections to sort out to complete the upgrade project.  

I took charge measurements today but could not make it through the Long_Trend.m due to some nds2 errors from some maintenance. The plots from ESD_Analyze_many.m looked good though. I will try again tomorrow.

Ed, Keita

We re-aligned the OpLevs at for ITMY,ITMX, PR3 and SR3.

John, Chandra

Removed and replaced pneumatic actuators on LLCV at CP 7 & 8 with electronic actuators. Actuators may be slightly overfilling until power is wired to device to retain auto feedback.

Richard is working on fabbing two 24 to 12 V boards to power them up.