CS: Pump temps and vacuum pressure are within specs. No adjustments made. EY: Pump temps within spec. Made slight increase in vacuum pressure. EX: Pump temps are high due to scroll compressor running. Opened up bypass to add more cooling. Closing FAMIS ticket #7525
TravisS, RickS
Yesterday afternoon, we transitioned Xend to Laser Hazard, energized the Pcal laser, checked the beam centering on the Pcal Receiver Module power sensor, then transitioned back to Laser Safe.
The beams are well-centered on the power sensor aperture (see attached photo), indicating that the beams are still where we want them on the ETM surface.
After the unsuccessful search for the AS_C signal today (see 41962 and comments), I wanted to get some of the DRMI alignment better. This will help us be sure that, when we go into HAM6, we're working with a roughly okay beam.
I started with a place that I knew from last week that I could lock PRX. While locked in PRX, I dithered PRM in length and rotated the RF phase of REFL_9 and REFL_45 until the PRCL signal was all in the I-phase. This took REFL 45 from an old value of -13 deg to a new value of -53 deg. This took REFL 9 from an old value of -90 deg to a new value of -30 deg. Net -40 deg for RF45, and +60 deg for RF9.
The only mirror (out of PR2, PR3, BS, ITMX) whose alignment was different from the single-bounce alignment was PR2. So, I noted my PRX-locked value for PR2, and went back to the single-bounce value. I walked PR2 toward my PRX slider values, while moving SR2 and SR3 to keep beam on AS_A and AS_B. In the end I was able to lock PRX while still seeing beam at the AS port. I then misaligned the PRM and aligned the SRM, giving me an SRX configuration. I did a very rough alignment of SRM until I saw SRX fringes. I then misaligned SRM, and ITMX, and realigned ITMY. I moved ITMY around until I saw beam on the AS WFS again (since we don't have an AS camera yet). Once I realigned ITMX, I had some weak MICH fringes. I tweaked up the alignment of ITMY, and now have pretty good MICH fringes.
Depending on what we decide in the morning meeting, I may work more on locking and aligning DRMI, although the beam we have should be good enough to see signal on AS_C, certainly within picomotor range. Since we're seeing beam at AS_AIR, we can't actually be all that far off......
I installed a microphone and accelerometer in the PSL to help study the vibrations sources.
After evicting a tiny snake out of the X-End VEA floor, it just didn't want to go, I went to check on the purge air skid. This system was having issues keeping up with the demand.
After shutting off 4 out of the 5 compressors found that we had 3 relief valves stuck open, wasting lots of air.
All 3 bad relief valves were replaced and the system appears to be healthier now, after 30 minutes of the skid running on all compressors the dew point was measured at -18.2 oC.
CP4 pressure on 450 l/s turbo pump is 2.5e-9 Torr. Will take RGA scans tomorrow. Bake enclosure will be removed tomorrow.
Attached is an SEM analog scan (in red) from LLO's cold, isolated CP4 (pumped with small 55 or 75 l/s IP) at their EX in comparison with the preliminary scan (in black) Kyle took last week of LHO's baked CP4 pumped by 450 l/s turbo. Note that LLO's scan is from an SRS model and LHO's is from a Pfeiffer Prisma Plus model so the Torr to amp ratios are different.
Recording pressures and RGA scans weekly with HV1600-10 activated at EY. H2 reduction is most significant change.
PT-428 = 1.62e-7 Torr (NEG housing hot cathode gauge)
PT-410 = 1.21e-7 Torr (BSC 10 main volume cold cathode gauge)
Scan from 4/26, two weeks prior.
In an effort to complete work at the vault and vault power room prior to the dry season we have been pushing hard to get the readbacks for the Seismic and LEMI channels in the vault operational. Many issues impede this work, including but not limited to bugs, mice and their biproducts, bees, goat heads, snakes, dirt, weather, spotty communication to the control room, etc... Currently the seismic reset resides inside of a bees nest.
The FIBOX is a system that can read in an audio signal (seismic and magnetic LEMI signals) and transmit them via multi mode fiber over long distances. Our system has three Seismic channels, X, Y, and Z, and two LEMI channels X and Y.
Over the past week we have tried resetting the FIBOX's, replacing them with freshly calibrated units, we carried everything back to the lab and tested it, carried everything to MID X and tested the throughput. After testing the FIBOX's at MID X with a local fiber, I can report that all of the channels are working as designed in this controlled environment. The ADC inputs also work when a signal is injected into them.
When the FIBOX's are placed in the vault the seismic channels look bad, I assume it is because we cannot reset the seismic system (reset located in bees nest). The LEMI signals also look bad. Next step will be to read the signals directly with an oscilloscope and inject signals directly with a function generator out in the vault.
Everything is reconnected in the vault as of 3:00pm PDT.
Bubba is aware of and working on a resolution to the bees.
TITLE: 05/14 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Work today including: ISC team in HAM6 investigating AS_C and viewports, EX PCAL checks, ETMX prep for AMDs later in the week, PEM PSL testing.
LOG: See attached
HAM4 HEPI is unlocked and the Chamber went to fully isolated with out issue.
Ran Range of Motion tests of 600 micro units on X Y & RX RY. See attached for the local sensor response: First is the X & Y. On this one I've taken the absolute to show the over lap better. Can't really explain why they don't overlap on the smaller X drive excursions when it can do the larger Y. This would appear to not be an interference issue but must be some force problem. Again, can't explain at this point. The second plot shows the tilting offsets and suggests the vertical motion of the greater RY excursion starts to run into something, note: I dod not take the absolute value this time. I'll look into the details to see if it guides me to a particular spot. Meanwhile, there is plenty of range available for operation.
Added 100ml cooling water to PSL crystal chiller. Did not add any water to diode chiller. Both filters are clean and clean. No noted debris or discoloration.
Should read "Both filters are clean and clear"
Alexei, TVo
Ran a measurement OMC mismatch from of single-bounce beam (off of ITMX) as a function of SR3 heater temperature.
The power to the SR3 heater was gradually ramped from 0 W to 5 W (corresponding to a temperature range of 25 C to 70 C) over the course of several hours to account for the SR3 time constant (about 15 minutes according to G1501373)
The OMC was scanned by applying a sawtooth ramp voltage to PZT2_EXC with a period of 20 seconds and amplitude of [0,120] counts.
There were also some OMC alignment loops that were closed during the scan (AS_A, and AS_B?) (I'm sure TVo will correct me if I'm wrong).
The mismatch was computed by measuring the ratio of the second order peak to the zeroth order peak. The mismatch data was taken by an OMC scan analyzer tool that I've been developing, which tries to track the zerorth and second order peaks
in time by essentially plotting the PZT2_EXC channel against the AS_DCPD channel. I will upload the tool on gitlab and pypi hopefully sometime soon when it can be used without needing me to watch over it.
The final plot ( m_vs_temp_1_2.png ) is the summary of the measurement, which is a combination of two sets taken about an hour apart. The mean mismatch managed to drop by about a 1% over a 40 C change, with a fluctuation of about 1% for any given temperature. I'm not really sure why the mismatch data is so noisy (I confirmed that the tool was correctly tracking the heights of the peaks). I was also unsure what temperature load the SR3 heater could sustain ( G1501373 says that either 10 W (emitted?) or 87 C is the max).
I will investigate the single-bounce models of the IFO to see if the mismatch change is what we expect.
Just finished crunching the single bounce model of the SR3 actuator. Plot attached.
Plot was generated from the LHO FINESSE model with the most up to date measured parameters (found here).
The OMC eigenmode of this model was computed then back-propagated to the SRM AR surface.
A sample of beam parameters that are mismatched to the OMC eigenmode by 10% (i.e points that lie on the 10% contour in the plot) were generated following the method in T1800193.
Each beam parameter was then back-propagated to the BS.
The SR3 RoC change was varied between 0 mm and 32 mm and the beams were forward-propagated through the changed SR3 all the way back to the SRM AR surface.
All of the resulting beam parameters from this procedure are shown on the plot.
I've also plotted the most recent measurement I could find on alog of the single bounce beam parameter.
From the plots on the post that I originally posted we can see that the mismatch imporves by about 1% over roughly a full SR3 actuation range. This combined with the information that our initial mismatch is about 10% puts us somewhere in the lower right corner on this plot.
My guess is that the observed astigmatism in the single bounce beam probably makes SR3 heater actuate on the mode differently to what I've modeled. I might look into performing the same analysis but factoring in astigmatism, but right now I don't know how to carry that out. Adding another degree of freedom (the other transverse axis) makes this difficult to conceptualize as a plot.
I've been asked to provide the code for the actuation maps. The notebook for generating the SR3 actuation map is on ligo gitlab linked here.
The only real dependency for this code should be the latest commit of pykat (15/05/18 or later). Let me know if this doesn't work, doesn't make sense, or is somehow wrong.
Thomas, Dan Brown
This morning we wheeled out the SRM heater to the north side of HAM5. The CO2 laser cannot be switched on currently until the SOP is complete, the controller for the CO2 is on Thomas' desk. The goal today was to try and align the table to the two steering mirrors and the holes in the SRM baffle. We managed to center on the ZnSe viewport and the first steering mirror. Changing pitch and yaw there we could trace the beam around the edge of the first baffle hole, we were unable to do the same on the output baffle hole. When we believed we were centered correctly the alignment beam could be clearly seen on the baffle on the HR side of the SRM, we're currently unsure whether that should be the case or not. We also do not have a good view of the beam dump from the north side which makes trying to align into it difficult. We still have some alignment work to do here before we are ready.
The north HAM5 door area is now sectioned off with screens between the squeezer table and the clean room, pictures of the area are attached.
Eddie, Corey
Eddie exported the AWC mirrors and beam dump from the SolidWorks model so that I could add them to the Zemax model. The attached .pdf shows the path of the CO2 beam into HAM5.
Aidan confirmed that most of the power will be absorbed by the optic, so only the beam labeld 'AR Reflection' will be present with the actual CO2 beam. I included the other beams (transmitted, HR reflection) in the model since the alignment laser is not absorbed, and thought it may aid with alignment.
Betsy and Jason conducted the initial alignment as documented in:
LHO aLOG 39669 https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=39669
Is there any reason that this successful initial alignment would not be easily recaptured? Seems that there should be enough adjustment possible to sort this out.
Not really any major issues. It's just awkward to check the alignment using the reflections on the SRM baffles: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=41724. We asked Corey to check where we should see spots on the SRM HR baffle so we had a better idea of what we were looking at.
We managed to get the CO2 beam on the SRM and induce a lens using this method yesterday: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=42254
Daniel, Jenne, Fil, TVo
In preparation for this weekend's work to try to do an OMC Scan measurement while varying SR3 RoC, I decided to try to make sure our new alignment of the IMC could make it down to HAM6. I was able to get light on AS_A_DC and AS_B_DC and close the centering loops but I noticed that AS_C had no light on it which is very odd.
All the electronics were turned back on from our grounding loop searching from April 26-27 however, the attached trend shows that something dramatic happened to that QPD segments around Apr 27 2018 15:53:41 PDT which caused the individual segments to get much noisier and the sum to drop dramatically. I'm pretty sure we were laser safe at the time so it wasn't like the a beam falling off the diode. So I thought this might be some sort of electronics problem like a disconnected cable in the midst of the madness, but everything in the rack to the chamber feed-through seemed to be connected properly, Fil and Daniel tested the in vacuum QPD chain from the outside with a multi-meter and confirmed that there is a connected diode in chamber.
So maybe we're just not seeing light? Again, this seems strange because we see light on both AS_A and AS_B.
In general, this won't deter our work this weekend but we might want to get this figured out before we open the doors early next week or put it on the task list for the chamber. One method we haven't tried is looking for AS_AIR and seeing if that comes out of the viewport. Also, there is a picomotor we can actuate to steer the beam onto AS_C, but I'm holding off on this unless we know what is going on.
Made a quick check that the downstream electronics works:
Thomas, Dan
We checked the AS air and OMC transmission beams coming out of the north HAM6 viewports. They were too dim to see with cards but visible with the IR viewer, both are clearing the viewports fine
After more looking in the viewport with Keita, Daniel and TVo (including turning the illuminator on/off, and sadly seeing no response on AS_C, although we did see a tiny response on the OMC QPDs which are inside the shroud), I worked on picomotoring the AS_C steering mirror, in a last-ditch effort to see if we could ever see a signal. The answer so far is no. Using the largest picomotor steps, I went +/- 6 steps in pitch and +/- 10 steps in yaw from the previous nominal. I thought I saw a beam briefly, but it turned out to be something upstream, since it affected all of the AS diodes (including the WFS, which aren't affected by this steering mirror). I did a rough raster scan of the picomotor actuation, mapping out a rectangle. When I was finished, I put the picomotor back to the place that I started, so even though it won't have gone precisely to the old pointing, it should be close.
AS_C seems to have a lot of 60 Hz + harmonics noise, more so than the OMC QPDs do, when the IMC is offline (MC2 misaligned). Daniel points out that this shouldn't affect our ability to see a DC response, and the rest of the electronics chain passed some basic checks, but it does seem like a concern.
Daniel pointed out to me that the picomotor to HAM6 likely wasn't connected since ISCT6 isn't really back in it's final position yet. And, he was right. So, today I connected the HAM6 picomotor controller using some 10' DB25 extension cables, and then re-did my raster of the AS_C pico. Step size of "magnum", 10 x 10 grid. I didn't see anything at all that looked promising. The picomotor is back nominally where I started, although it's of course not precise. I think we're going to have to pull the north door of HAM6 tomorrow, as we discussed was a possibility at this morning's meeting.
In case you find a problem with the QPD diode, the head, or the invac cable:
The cable currently installed for AS_C is D1101654 / S1202409 (40"). It has only one head (Head #29). The diode installed is Q3000 InGaAs QPD #18.
cf. LHO ALOG 12244
There is only one spare InGaAs QPD diode (#15) left as an LHO spare.
The spare 40" cable is D1101654 / S1301546. This cable has no head. Therefore, to use this cable, the head needs to be transplanted from S1202409 or D1000231 S1202412 (36"), which has two heads (#34 and #35) and two diodes (#55 and #76) attached.
See also: E1101174
Betsy and Travis told us that we can just use the top blade to rotate TMS is we're talking about O(100urad) instead of O(many mrad), so we did just that.
The procedure was: Remove ERM protection cover, adjust EX bias so the optic is centered in oplev, inject green laser, set the TMSX offset to get the retro-reflection on the table. Then loosen the blade (which makes TMS sag so no retro-reflection), turn the adjustment screw, tighten the blade, look where the beam goes, repeat.
It turns out that 1/4 turn of the adjustment screw took out 400-something urad, then Travis tried 1/16 of a turn and that took out the rest.
In the end TMSX alignment sliders were set to [P,Y]=[-74,5] urad, almost perfect for Y, and P is no worse than yesterday where it was [91,-585].
We also adjusted BOSEM depth. For F1, LF and RT we recently measured the open values and set the depth (41675) so didn't bother to remeasure open values but we reset the depth anyway as RT seemed to have drifted out.
For F2, F3 and SD, old and new offset as well as open value as of now are:
| Open today | New offset | Old offset | Reading before adjustment | Reading after adjustment | |
| LF | NA | NA | -9350 | ~9.9k | ~9k |
| RT | NA | NA | -13475 | ~16k | ~12k |
| F1 | NA | NA | -10515 | ~10.9k | ~10.7k |
| F2 | 18.1k | -9050 | -11164 | ~11k | ~9k |
| F3 | 23.2k | -11600 | -14150 | ~18.5k | ~11.3k |
| SD | 22.1k | -11050 | -14372 | ~11k | ~11.5k |
Inventory info: S/N of F3 BOSEM is 296, F2 301.
Travis and I have taken the 6 DOF transfer function measurements of TMSX. While nothing says it is rubbing (good), there still seems to be something wrong with the top 2 BOSEMs (LF and RT), see attached. The TFs that utilize these 2 BOSEMs show a DC offset across the entire measurment.
Will continue forensics later. Maybe a setting somewhere? TBC...
The changes in the TF look predominantly just a factor of 4-ish increase in sensitivity, and it makes sense to me.
We know that BOSEM LF and RT sensitivity was much smaller before I and Corey repositioned/replaced these on Apr/25. If you look at my alog and Jeff's comment attached (41675), their physical sensitivity increased by a factor of 2.8 and 3.3 respectively for LF and RT, then Jeff changed the calibration constant for LF from 1.295 to 1.604 (a factor of 1.24) and for RT from 1.146 to 1.113 (a factor of 0.97).
The overall sensitivity of LF and RT increased by 2.8*1.24=3.5 and .97*3.3=3.2, respectively, i.e. roughly the P and V sensitivity should have increased by a factor of ~(3.2+3.5)/2~3.4. And 4/3.4~1.2, that's not a big number.
I assume that the reference in Betsy's plot was taken when the sensitivity was already small.
