Sheila, has Transitioned the LVEA back to LASER SAFE.
TITLE: 05/16 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
Work is ongoing in HAM1 to finish up all the checks we need done before doors go on next week.
The RM/PM damping issues that we've been seeing (84427) are most likely due to the higher purge air in HAM1 since they had been working fine two days ago when the purge air had been turned way down, and yesterday and today when the purge air had been turned up, were not working. We'll be able to better confirm this on Monday during a time when we can have the purge air very low and there isn't any activity happening in HAM1. RM1, RM2, and PM1 have been put into SAFE for the weekend.
The LVEA is currently LASER HAZARD.
Sensor correction is on in the LVEA (SEI_ENV: LIGHT_MAINTENANCE_WINDY and SEI_CONF: NOBRSXY_WINDY).
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
14:52 | FAC | Kim | LVEA | YES | Tech clean | 15:40 |
15:28 | ISC | Sheila | LVEA | YES | Transitioning to laser hazard | 15:42 |
15:28 | VAC | Jordan | LVEA | YES | Purge air checks | 15:44 |
16:01 | ISC | Sheila | LVEA | YES | Turning off a sideband | 16:08 |
16:36 | ISC | Marc, Sheila | LVEA | YES | Turning on HV for HAM6 | 16:41 |
16:37 | VAC | Janos | LVEA | YES | Checking things | 16:45 |
17:10 | ISC | Sheila | LVEA | YES | Turning sidebands back on | 17:26 |
17:53 | ISC | Sheila, Elenna | LVEA | YES | Final beam checks in HAM1 | 20:13 |
20:04 | SEI | Michael, Shoshana | EY | n | Minor wiring on BRS | 20:47 |
20:14 | VAC | Jordan | MX | n | Vacuum measurements | 21:46 |
20:47 | PEM | Robert | LVEA | YES | Looking for scattered light in HAM1 | 21:57 |
21:46 | VAC | Jordan | LVEA | YES | Vacuum measurements | 21:57 |
21:55 | TCS | Tony & Mitchel | Mech room | N | Chiller water checks. | 22:06 |
22:07 | CDS | Oli, Marc | CER | YES | Checking out PM1 coil drivers | 22:14 |
22:16 | ASC | Sheila & Elenna | LVEA HAM1 | Yes | Final Beam Checks. | ongoing |
22:43 | VAC | Jordan | LVEA | YES | Turning HAM1 purge air down | 22:46 |
23:13 | VAC | Jordan | LVEA | YES | Turning purge air back up | 23:14 |
We wrapped a little early today because of 20mph gusts, but we got most of the second set of scrim attached this morning. Still have to finish the top level wrap with the 3/16" wire and do the vertical wrap on both ends. We'll pick it up next week, probably after doors go back on HAM1.
This alog summarizes the measurements done with an ISC whitening chassis that implements ISC whitening boards D1001530-v7 using a 9V battery at the input.
Several issues were found:
Plot 4 shows the 9V input noise using the optional whitening stages. A whitening stage consist of a 1Hz zero and a 10Hz pole.
Plot 5 shows the same plot but with the 300Ω resistors removed, the 3kΩ resistors replaced with metal films, and the inductors at the power supply shorted out.
Plot 6 is an overlay of Plots 4 and 5.
Jennie W, Sheila, Elenna
In order to get data for mode-matching and for Elenna to get data to calibrate sideband heights we ran some mode scans after the SR3 heater was turned on last night.
16:55:24 UTC Carried out single bounce OMC scan at 10W PSL input with sensor correction on HAM6 on, high voltage on for PZT driver in HAM6, sidebands off , SRM mis-aligned, ITMY mis-aligned, DC 3 and 4 on, OMC ASC on.
Excitation freq changed to 0.005 Hz as the top peak of the TM00 mode looked squint so could have been saturating. Lowering this frequency prevented this.
Ref 15-17 corresponds to dcpd data, pzt exc signal, pzt2 dc monitor.
Then mis-aligned ITMX and aligned ITMY (Sheila had to re-align SR2 to centre on ASC-AS_C).
Measurement starts at 17:08:18 UTC.
Ref 18-20 corresponds to dcpd data, pzt exc signal, pzt2 dc monitor.
Traces saved in 20250516_OMC_scan.xml. The top left plot is the first scan bouncing beam off ITMX, the second scan is the bottom right bouncing off ITMY.
The top right is the two plots of the PZT2 DC voltage monitor. That is, the current voltage applied to the PZT. The bottom left is the plot of the voltage ramp applied to the PZT2 on the OMC for this measurement.
The ndscope attached shows the power in mA transmitted through the OMC on the top, then the PZT used for the scan DC voltage underneath, then the input PZT voltage underneath that, then the reflected power from the OMC in mW, then at the bottom the SR3 heater element temperature in degrees.
Elenna did two more scans in single bounce with sidebands back on and different modulations depths in each.
See Elenna's comment on her previous measurement where this saturation happened.
Turn off the sidebands - instructions in this alog.
Sheila and I ran one more OMC scan with sidebands off after OM2 heated up. Attached is the screenshot with scans off both ITMX and ITMY, data is saved in [userapp]/omc/h1/templates/OMC_scan_single_bounce_sidebands_off.xml
I also ran two OMC scans, single bounce off ITMY, 10 W input, with the sidebands ON. One measurement I ran with the sidebands set to 23 dBm and 27 dBm (9 and 45 MHz) and another set to 20 dBm and 21 dBm (9 and 45 MHz). I will use these measurements to calibrate the modulation depth. Data saved in /opt/rtcds/userapps/release/omc/h1/templates/OMC_scan_single_bounce_RF_cal.xml
SR3 heater was on for this measurement but it should have little effect on my results.
Looked closer at these HWS signals during SR3 heater heat up and cool down. In all these plots, the two t-cursors are used as the reference and shown HWS live image.
Some strange things:
Fri May 16 10:06:36 2025 INFO: Fill completed in 6min 33secs
Jordan confirmed a good fill curbside.
Dry air skid checks, water pump, kobelco, drying towers all nominal.
Dew point measurement at HAM1 -42.1 °C
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TITLE: 05/16 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: MAINTENANCE
Wind: 6mph Gusts, 3mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.09 μm/s
QUICK SUMMARY:
Most of the work for today involves final checks for HAM1
Last night RM2 was left in DAMPED with the damping loops on, whereas RM1 asnd PM1 were also in DAMPED but their damping loops had been turned off. The loops on RM2 excited the suspension until it was causing overflows. This continued all night. It seems strange that the loops that were damping well two days ago are now not damping (ndscope1). I noticed that turning off only the L damping solved the issue of the MASTER_OUTs slowly increasing.
Doing some tests (starting in SAFE and then going to DAMPED), it looks like damping is fine for the first few minutes, after which it very quickly starts exciting instead of damping (ndscope2, ndscope3), and the voltmons start going crazy. I did this test a few times with the same result every time.
Doing the same test but immediately switching L damping off as soon as it turns on, we stay just damping P and Y and have no issues with oscillations or saturations (ndscope4).
I am not sure if this means that the issue is specifically with the Length damping? I am putting RM2 in SAFE for now and I'm going to try the same tests on RM1 and PM1 to see if the same issue exists there.
[Shoshana, Michael] We've started preparing to install the BRS mass adjuster to the End-Y BRS. The plan is to follow the same procedure/same parts as the End-X install outlined in LIGO-T2400043 and SEI log 1886 (https://alog.ligo-la.caltech.edu/SEI/index.php?callRep=1886). We've taken apart the BRS and discovered that doesn't match the designs on the DCC. How the parts are arranged blocks access to where the pico-motor mount should attach, but we think we have a work around that should work. The electronics/wiring of the BRS is as expected and we've finished all the wiring for the pico-motor so that it should attach to the feed through. Assuming all goes well we plan on installing the mass adjuster parts and begin testin.
[Shoshana, Michael] We've managed to get all of the hardware/parts installed in and we've closed up the BRS chamber. We had to add an inch of shims beneath to motor mount in order to get it to fit/align properly, but otherwise there were only minor complications during installation. We've tested the pico-motor and the mass adjuster using the pico-motor driver that we brought from UW and both seem to work fine. For in air balancing, we left the new mass adjuster centered to increase range for future adjustments for when the BRS is pumped down and running, and tried to just stick to moving masses that are inaccessible when the BRS chamber is pumped down. We unfortunately reached the maximum range with the internal masses and had to slightly move the manual mass adjustment system (what is currently used to adjust the center of mass) from center, but that might be returned to center after we re-balance it when it's pumped down. Right now the resonance frequency looks to be around ~7mHz (around 130 second period) which is about the same as it was before Mass Adjuster installation, but we'll check again after the chamber has been pumped down. Tomorrow we'll finish all of the wiring and electronics to hook up the pico-motor to the LIGO system. The plan is to pump down the BRS chamber tomorrow and re-balance and test the pico-motor some more. The reference pattern has a higher intensity than expected and we aren't sure why. Right now our best guess is that the light source drifted slightly, and we'll look into it more tomorrow.
EPO tag for BRS pics
[Shoshana, Michael] Pumped down the BRS chamber overnight and started the ion pump this morning and got it down to 1.9e-6 Torr before we left end End-X. We also wired up the picomotor to the LIGO picomotor controller system. It is hooked up to the 7th channel X-direction and we tested it out and were able to hear it spinning for both directions. The BRS's thermal insulation was reapplied the box closed and the temperature sensors and heating plate were all re-attached and plugged back in. The reference beam's intensity has gone down to be closer to normal somehow, so it doesn't seem to be anything to worry about We might go back to End-Y one more time tomorrow to clean up the wiring and do a final check of the vacuum pressure. We waited for the temperature to equilibrate a bit before balancing because we were hoping that as the temperature rises it would drift back to center, but we ended up using the mass adjuster to try and balance it. It looks like the + - wires for the damping were switched, meaning when the damping was on it would ring up the BRS. Fixed by changing a line in the BRS code[IF H1_ISI_GND_BRS_ETMY_CAPDRIVE>=0] by switching the [>=0] to [<=0] and switching [H1_ISI_GND_BRS_ETMY_CAPOUTL] and [H1_ISI_GND_BRS_ETMY_CAPOUTR], and [H1_ISI_GND_BRS_ETMY_RELAYL] and [H1_ISI_GND_BRS_ETMY_RELAYR] FROM THE END-X INSTALL: Coupling/decoupling move: 1.25k steps Maximum: +-140k steps Be careful: +-100k steps NOTE: MOVING PICOMOTOR +(POSITIVE) DIRECTION TRANSLATES TO MOVING THE BRS UP TOTAL MOVEMENT TODAY:+21k steps
Centered both ETMY and ETMX BRSs. For ETMX net movement was +2200 steps, for ETMY net movement was -3200 steps. For ETMX we saw that the DRIFTMON was moved by about ~3.27 counts per step, and ~2.3 counts per step for ETMY
Cleaned everything up for the ETMY BRS and relabeled all the wires. The final reading that we saw for the ion pump was 9.9e-7 Torr (186uA, 6950V) which seems about right. We left some extra mass adjuster parts with Jim just in case.
Shoshana, Michael
We took tilt subtraction spectra as a final life check of the BRSs. Both BRSs appear to be in good working order and doing their jobs well.
Oli, Keita, Elenna, Jennie, Sheila, Ryan S, Rahul, Betsy, Camilla
Day 1: 84193, Day 2: 84228, Day 3: 84230 and 84239, Day 4: 84274, Day 5: 84292
In the morning Keita and Jennie aligned the POP flashes on the periscope mirrors and M10 dichroic. The height of this beam is 3.75" on these mirrors to account for the ALS green beam being 13mm above the POP beam. Keita was a little concerned about the height of the top periscope mirror so we'll need to check the green ALS beam carefully on this and if it 's near clipping we may need some in-vac pico-ing.
Rahul then moved PM1 to it's final position. Elenna and Rahul checked that the signed of the PIT and YAW sliders were correct.
Shiela, Rahul and I then worked on centering the beam on PM1 and L2 without the 90/10 M12 in place, so that we could later have enough power to beam profile the POP single bounce beam. To get the beam height back up to 4" at PM1, Rahul needed to pitch PM1 mechanically.
Oli then increased PSL input power to 20W, we aligned to POP single bounce and Sheila and I took beam profile measurements before PM1 and after L2, details in 84307.
Elenna, Rahul and I then replaced the 90/10 M12 and recentered the beam on PM1 and L2. We started aligning the POP air path but aren't happy with it, dumped the beam and will continue to work on.
Betsy let in the PSL ALS beam into HAM1 by opening the light pipe and I dumped it straight away. See 84312.
Today we plan to: align the POP, REFL and PSL ALS beams out of the chamber, open the X-arm check the green ALS beam alignment on the shared optics and off the table, including rolling up ISCT1 and adding the VP simulator. The POP LSC/ASC diodes and all beam dumps still need to be aligned and checked.
Keita and Jennie's log on the work done in the morning is 84308.
Just adding a clarification. "Elenna and Rahul checked that the signed of the PIT and YAW sliders were correct. "
We confirmed that adding a positive pitch offset in the alignment slider of PM1 results in PM1 pitching downward, as expect in a right handed coordinate system, and verified by watching the beam reflecting off PM1 shifting down. We also confirmed that a positive yaw offset results in the optic rotating left (as seen from behind the optic), again as expected from the right handed coordinate system, and verified by watching the beam reflected off PM1 shifting left.
I went back and forth a few times with the offsets while Rahul held an indicator card in front of the optic to watch the beam move to see the response of PM1.
I took two single bounce OMC scans today with the help of TJ and Tony. Here are some notes to future me and others to reference if we want to do single bounce scans:
Edit to add: unfortunately the scan results from today look pretty bad. In short, the peaks look "lopsided" somehow, and so I'm not sure the results are usable. Looking back at Jennie W's previous scans, it looks like she had to slow them down to 200 second scans. I only did a 100 second scan with amplitude 105 so maybe I scanned too fast. I'm not sure what the correct resolution of this is, because the scans I did in 2022 were 100 second scans and the results were fine. Adding this note here for reference in the future to think about the appropriate scan length and amplitude.
Jennie, Sheila, and I ran OMC scans this morning and realized that the proper way to slow down the scan to avoid weird saturation effects is to reduce the excitation frequency in the template. The nominal templates have excitation frequencies of 0.01 Hz, so sweeping over 200 seconds just sweeps at the same speed twice. To sweep once, slower, you have to increase the sweep time to 200 seconds AND reduce the sweep frequency to 0.005 Hz.
Sheila and I want to note some things that are "obvious" but easily forgotten:
Just adding a note:
As of the end of the day, Sheila and I have left the sidebands OFF, and the HAM6 high voltage ON (per WP #12545).