I have updated the CDS MEDM overview screens: added new h1lscaux model changed the WD colors to support HIFOX
Fluid level trip. Found the Pump Controller (not servo) red lite off--other than power failure, sure indication of Fluid Level trip.
Turn on Process:
Since I've hardwired the FWD button, the controller will start at the Servos Command as soon as the Green Start Button is pushed, so:
Must turn down the Servo Output--On Pump Controller medm set servo set point to zero or manually run down the output.
Press Green Start button on Controller Cabinet, Ramp up servo set point to 80psi, or step up output manually to near 80 and then switch servo to Auto mode.
Warning--Don't overshoot the pressure too much or the level may trip again or if you really overshoot and the level doesn't trip, the pressure relief valve will release.
After I got the servo running again, I pulled up the trip switch and found the trip level was only ~1/16" below the run level. Of course to do this test you have to trip the switch and start all over again. I then lowered the switch ~1/4" so we should be good for a while.
I have a scale on the site glass and a white board logging the running levels and now I have a trip level. We have been trending down a bit over the past few months. I have a couple minor leaks at the pump station, maybe something like a teaspoon a month. That combined with evaporation and the large servo load (really minor affect I believe) led to the trip. I'll start a regular maintenance routine of noting the running fluid level and lowering the trip switch to keep ahead of it.
Patrick T., Sheila D. We went to check on the H1 PSL environment. We verified that all the HEPA fans are off. We couldn't tell if the make up air fan was running, so we commanded it to run again. It was and still is set at 20% fan speed.
Something odd is happening with the IOC for the dust monitors at end Y. The medm indicates that the IOC has died. Telneting into the procServ server for it appears to automatically restart it. This happened yesterday morning as well.
I have attached two plots of the dust counts in the H1 PSL enclosure from 8 AM yesterday to 8 AM this morning, one from the laser room (Location 1) and the other from the anteroom (Location 2). These are from the newly installed Lighthouse Remote 3014 particle counters. The counts are normalized to particles per cubic foot. The samples run for 20 seconds with no hold time between them. The black traces are counts > .5 microns. The blue traces are counts > .3 microns (including > .5 microns). The scale for particle counts is on the left. The scale for temperature and relative humidity is on the right.
This morning the TMS positions to hit the baffle PDs were the same as last night 10001
Alexa moved PR3 by 1.3urad in PIT and 0.7urad in YAW to center the single shot beam on the spot on the camera on ISTC1. Then we realinged the cavity, moving the ETM pit by hand +3urad in PIT to see cavity flashes around 800 counts.
We could not engage the PIT and YAW IAL servos at the same time, this would drive the alingment off. We engaged YAW alone first, this was stable but didn't improve the build up. When we tried to then egage pit it would drive the alingment off. Engaging pit by itself first improved the build up, once this had run for a few minutes we could engage yaw. Now we have around 920 counts on the TRX PD, and -31 dBm beat note power.
Completed installation of an ITM-X pair of ring heater segments, and associated UHV cables for the lower structure. We assume that the upper UHV cable (D1001521) and bracket (D1001756) -currently installed on the existing ITM-X upper structure- will be (eventually) mated to this lower structure installation. Upper RH: 44.9-ohm Lower RH: 45.6-ohm Photos are attached. See also, the following records: https://dcc.ligo.org//LIGO-T1300463-v21 https://ics-redux.ligo-la.caltech.edu/JIRA/browse/ASSY-D1001838--V7-111 https://ics-redux.ligo-la.caltech.edu/JIRA/browse/ASSY-D1001895--V8-201 --> the temp sensor head broke off at the time of installation, but free cable secured
Sheila found the two TM ISIs tripped--Looks like a big event hitting the microseisem plus we are having a bit of a wind event. Sheila was unable to get the ETMx to go up but she was using the 750mHz blends and that may just not work for Lvl3. We likely need to tailor some blends to work with Lvl3 that don't use the T240s. I was able to get the ETMx ISI Stage1 up directly to Lvl3 with TCrappy blends as the Bias Position were not far from the targets. And Stage2 is still using Lvl2 controller with TCrappy blends.
Sheila had no issues getting ITMx back up. This ISI had been on since Friday 0816utc--not bad.
All HEPIs are operational and running position loops.
The ITMY & BS Appear to be in the same state as I left them last night. According to the WD last trip time these last tripped about 10:30 & 11:30 yesterday am. They weren't up during all that time though as we were ignoring them.
As far as the trips on the TM ISIs, there were some significant EQs around the globe in the hour before the trip( such as a 6.9 ~50 minutes before in China), we had elevated winds (no wind monitor at Ends) and running these very aggressive controllers all may have combined to causes these near simultanios trips (8 seconds apart.)
In case you didn't catch it -- the large event was most likely the 6.9 Mag Earthquake in China that Aidan noticed. It took down LLO's seismic platforms too! We *really* need to get legible ground motion plots posted on the control room walls that remain functional for more than a few hours and are in physical units. This would have been obvious in the S5/S6 era control room.
These plots are on the walls at LLO at present. We are still working on getting snapshots posted to the web site for off-site inspection.
plots attched.
For the ITM it was basically a one click recovery (using Tcrappy blends and isolate level 3), I tripped the ETM trying to bring it up (I tried 750 blends and level 3 on stage 1, that didn't work).
Hugh saw that the biases on the EMT ISI were fairly small, and brough it to stage 1 level 3 with T crappy, stage 2 level 2 Tcrappy.
The microseism has been rising over the last 20 hours, and there was a big spike somewhere around 2 am. (we are currently at around 5 on the strip chart, I'm not sure what the units are).
The tripping may be due to the M6.9 earthquake in China (see LLO aLOG entry ) which occurred at about 3:20 AM CST (or 1:20 AM PST). It tripped all our watchdogs
(Alexa, Hugo)
ETMX watch dog tripped at 9:45am. Similar spikes seen in ISI.
What happened at 9:44am PCT: Fluid pressure drops on HEPI (No fluid pressure on MEDM screen of HEPI pump. reason still unknown). HEPI drive increases to meet targets, but hepi does not get physically driven due to the abscence of fluid pressure. The servo increase the output drive to compensate for it to the point where HEPI trips (1). Once tripped, HEPI slowly (hydrolic system) comes back to its floating position. While slowly coming back, it saturates the T240s, which are included in the blend which is fed to the ISO, causing the ISO of the ISI to ramp up as well, and trip the ISI (2), 2 seconds after HEPI tripped.
Trip times:
HEPI: 1076262292 (1)
ISI: 1076262294 (2)
[Stefan, Lisa, Evan, Kiwamu]
Our goal tonight was to get the IR transmitted light centered on the transmon QPDs. A coarse alignment was established. We still need to do a fine alignment with the picomotors.
QPD centering:
We had never aligned this path with the actual IR beam, and neither QPDs had a beam on them. As discussed and suggested in the last integration meeting, we started this mission from a scan of the TMS in order to find an IR beam with the QPDs. Moving the TMSX in an almost random way, we found a beam which was flashing as the carrier light resonated in the cavity. The yaw angle needed to be twisted by roughly 100 urad to get the beam on the QPDs. Then, keeping the flashing beam on the QPD by steering the picomotors (M4 and M14), we steered the TMSX back to the nominal angle. This operation was successful. Then we moved onto a fine adjustment by locking the main infrared light to the arm cavity (the detail of the locking procedure can be found in alog 9644).
The fine tuning was very frustrating. We kept loosing the lock because of the roll mode of MC2 at 40 Hz (see awiki for HSTS resonances ) which then saturates everything and breaks the lock. Plus the spot position on the two QPDs didn't seem to be conversing by moving a combination of the two picomotors. The spot behaved as if the picomotors are degenerate. It is possible that, since the time for tweaking the picotomors was limited by the stability of the locking, we confused ourselves in the rush. This needs to be revisited. Anyway, a good news is that we now have a beam on both the QPDs and therefore we can do the fine adjustment anytime when we get a chance. Also we did an estimation of the power on the QPD, because we needed to clarify if the beam we saw was the main beam or a ghost. This is summarized in Evan's log (see alog 1006).
Some other things:
Later tonight, I tried to engage the AO path. Though I haven't succeeded. The idea is to have a low cross over frequency which then allows us to (re)insert the notch filter for the 40 Hz roll mode. However the loop was not so stable and everytime when I changed the AO path gain in the common mode servo board it simply broke the lock even if the gain seemed small enough. In addition to it, it became harder to lock approximately after 1:30 am probably due to some angular fluctuation in the arm cavity. I am too lazy to identify what optic is moving, but it is also clearly visible in the green ISCT1 CCD camera. Because of that, the IR locking doesn't stay more than 2 seconds -- the cavity build up in infrared drops extremely quickly due to the angular fluctuation.
End Station work:
Also, Lisa and Stefan went to the end X station to realign the single trans PD because the beam almost completely fell off from the diode during our picomotor adjustment. Because this PD was used for triggering the infrared locking, we needed to realign it. The alignment wasn't completed because the infrared light was not bright enough to easily work with. Then, it turned out that the bottom periscope mirror for the IR trans path was found to be very low reflective for some reason. It can be a wrong mirror. Indeed, Lisa and Stefan could see a beam with a card before it hits the bottom periscope mirror.
This mirror needs to be checked and possibly replaced by a proper one.
Just for reference the picomotors are now at: M4 X=-3273 Y=1796 M14 X=-1630 Y=-3515 In case any one wants to go back to approximately the position they were at before.
Also noted in alog 9731, most of the light the "IR trans" path has about 30-40 uW of green light, this may be what is transmitted by the lower persicope mirror.
[Stefan, Lisa, Kiwamu, Yuta, Evan]
We are trying to center the transmitted X-arm IR on the transmon QPDs, so that we can have an IR alignment reference. The expected power on each QPD is determined as follows:
These numbers give an expected power of 3.7 µW on each QPD.
What we measured was about 600 cts for the sum output on each QPD. We can back out the power on the QPDs as follows:
This gives a power of 4.6 µW on each QPD.
[Keita, Yuta, Evan]
Some corrections:
So the expected and measured numbers are actually much closer.
Written by Yuta
Xgreen frequency noise spectra from alignment fluctuation (see alog #9429, #9384 for more information) was calculated using oplev spectra of ITMX.
Even if we keep our sideband frequency to be 24.407079MHz and set the demodulation phase to maximize 00 PDH slope, the frequency noise is ~40 Hz in RMS when DC misalignment is 1 urad. Maybe we can work it out without using sideband frequency / demodulation phase tuning technique.
[Method]
1. Get calibrated ITMX oplev spectra (Thanks to Jeff !).
2. Frequency noise from misalignment(HOM) can be written as
fn(t) = k (a(t) + a0)^2
where fn(t) is the frequency noise, k is the conversion factor, a(t) is alignment fluctuation and a0 is DC misalignment. Note that this effect is quadratic and estimated k=1e15 Hz/rad^2 if we keep our setting as is (see alog #9429) and we assume differential angular motion of ITM and ETM.
The spectrum of fn(t) can be calculated using the spectra of a(t) from the following formula.
fn(f) = k^2 * (conv(a(f),a(f)) + 2*conv(a(f),fliplr(a(f)))) + 2*k*a0*a(f)
where conv is convolution and fliplr gives flipped array. conv(a(f),a(f)) gives upconversion term and 2*conv(a(f),fliplr(a(f))) gives down conversion term.
(see this document for derivation if you can read Japanese)
[Result]
1. ITMXOplevspectra.png: Measured ITMX angular motion from oplev. Note that spectra above 0.5 Hz is not measuring the actual motion.
2. HOMfreqnoise_0urad.png: Frequency noise from HOM in the case when DC alignment is perfect. This gives 0.3 Hz RMS.
3. HOMfreqnoise_1e-1urad.png: Frequency noise from HOM in the case when DC alignment is off by 0.1 urad. This gives ~4 Hz RMS.
4. HOMfreqnoise_1e-1urad.png: Frequency noise from HOM in the case when DC alignment is off by 1 urad. This gives ~40 Hz RMS.
Lisa
The idea was to revise the original estimate of the alignment-induced frequency noise between 1064 and 532 by using the actual motion of the test masses, after the improvement in the ISI performance.
Sheila, Stefan
The green arm maximum build-up had been trending down for a while to about 500cts, so we decided to do an arm alignment from scratch today.
Step 1: Baffle PDs
- We used the single shot beam to find the baffle PDs:
TMS PIT TMS YAW
PD1 220.0 -226.7
PD4 289.3 -288.6
Center 254.65 -257.6
PD1 is H1:AOS-ITMX_BAFFLEPD_1_VOLTS, and PD4 is actually H1:AOS-ITMX_BAFFLEPD_3_VOLTS
Step 2: Follow with the arm
- We still had some fringing at the old TMS alignment (P 279.3, Y -245.3 - yes, that's 27urad from the new position...)
- Thus we stepped TMS first in pitch and then yaw, and roughly followed with the ETMX and ITMX.
Step 3: Arm dither: Control ETMX and ITMX instead of ETMX and TMSX
- We changed the feed-back scheme to leave the TMS untouched, and only align the arm to the input beam.
- This was done by feeding back PZT1 dither (DOF2) to ETMX, and PZT2 dither (DOF3) to ITMX.
Step 4: Move PR3 to center the green transmitted beam on the first reference iris on ISCT1.
- The new (good) PR3 alignment is
PR3 P: -245.0 Y: -253.28
Step 5: Realign the green ISCT1 path
- We aligned the camera (and marked the spot on the monitor), realigned the transmitted green DC PD, and tweaked the COMM beat node up.
With this scheme we got about 915cts of green transmitted light - more than ever.
Step 6 (TBD): Diagonalize the dither drive matrix
- Evan and Yuta will do this soon.
After we realinged the beat note we had -31dBm on the RF mon.