B. Weaver, T. Sadecki

While we were investigating alignments of baffles, etc. while in HAM 4, we steered SRM such that the reflected beam went back to SR2.  Screenshot of the new SRM slider values attached as a comment. 

The dog clamps securing SR2 to HAM4 have been torqued to 8.5 ft/lbs (as close to 100 in/lbs (E1100411) as our torque wrench would allow) except for those on the north side of the structure.  The heads of the screws for the dog clamps on the north side are so close to the structure that the head of the torque wrench would not fit.  I attempted to duplicate the torque on these dog clamps by testing the already torqued dog clamps on the other sides of the structure and doing my best to replicate the force required to produce the torque using a normal flex handle socket wrench.  Upcoming B&K measurements of this structure will tell if I did well.

TITLE: 11/22 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 8mph Gusts, 6mph 5min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.87 μm/s
QUICK SUMMARY:  Late post, quiet morning so far.

Pep Covas, Evan Goetz, Ansel Neunzert, Brynley Pearlstone, Keith Riles

Summary:
We report on lines and comb investigations by the CW group that lead toward a version 1 lines and combs safe for cleaning in O2 H1 data. Run averaged spectra (covering all of O2 except a 1 month epoch, details below), provide a basis for data quality issues that can degrade CW/Stochastic searches. Any sharp spectral feature has a potential to contaminate and degrade astrophysical searches. We attempt to find all of the combs that are obviously non-astrophysical, and to determine any environmental influence for single lines.

If we can mitigate the most prevalent/egregious combs, this would go a long way towards improving the science that can be done with LIGO data. These combs are mostly at low-frequency (f < 100 Hz):

Comb spacing / offset
---------------------
1.0000 Hz / 0.0000 Hz
1.0000 Hz / 0.5000 Hz
1.0000 Hz / 0.9994 Hz
1.0000 Hz / 0.9987 Hz
0.9999862 Hz / 0.2503172 Hz
0.9878881 Hz / 0.0000 Hz

Notching or replacing data from the narrow bins only works as long as no other contamination is in nearby bins. Thus, it would be better to mitigate these combs in hardware.

A full list to the version 1 line/comb list can be found by following this link. Also through this link, one can find the un-vetted lines found in the H1 run-averaged spectrum.

Attached below are plots of the run-averaged spectrum in full, and in narrower frequency bands.

Details:
Using the C01 calibrated h(t) for O2 through July 2017 and C00 calibrated h(t) for Aug. 2017, we produce 7200 s long Short Fourier Transforms (SFTs), excluding CAT1 CBC vetoes. This mimics many CW searches and also provides good frequency resolution and coherence length so that most narrow spectral features that can impact CW searches can be found. We exclude the period from March 14, 2017 17:00:00 UTC to April 18, 2017 23:00:00 UTC to avoid the bad spectral contamination caused by the Pcal camera ethernet adapter (see aLOG 35640).

In the figures below, the noise-weighted run averaged spectra are plotted over the O2 run and notable features:
Figure 1, 20 Hz - 2 kHz; overall, better than O1
Figure 2: 20 Hz - 50 Hz; combs and lines galore (too many to list here)
Figure 3, 50 Hz - 100 Hz; more combs and lines but better than below 50 Hz, oddball narrow comb forest around 75 - 80 Hz
Figure 4, 100 Hz - 200 Hz; much better here than below 100 Hz, oddball narrow comb forest around 153 - 155 Hz
Figure 5, 200 Hz - 400 Hz;
Figure 6, 400 Hz - 1 kHz; violin harmonic regions are difficult/impossible to analyze (damping these modes may help immensely), oddball narrow comb forest around 970 Hz
Figure 7, 1 kHz - 2 kHz; violin harmonics problematic (again, damping will likely help), other oddball narrow comb forests around 1022 Hz and 1046 Hz

The procedure to find the lines and combs was mostly a divide-and-conquer manual inspection of the data. Narrow features were flagged, and combs could be identified by their common spacing. Some automated tools were helpful, but manual inspection was usually necessary. Combs are obviously non-astrophysical, so almost no vetting needs to be done, but the cause of these combs can remain elusive. 

Making the timing system LEDs stop blinking has reduced the amplitude of the 1 Hz comb with 0.5 Hz offset, the comb is not completely mitigated in O2 data. Further investigations are underway. Other 1 Hz combs also remain prevalent in the O2 data, probably GPS synced due to their narrowness. Coherence between the sites of these lines has not yet been established, but if GPS synced, then likely coherent (bad for any CW/Stochastic GW search).

Other lines that were found to have environmental cause in O1 and again appearing in O2 data are also in the version 1 line/comb list. Still other lines that are found to be correlated using the NoEMi tool on auxiliary channels are being vetted further using coherence tools. As further investigations proceed on other lines, we may have a version 2 of the lines/combs list.

Takeaway message: Mitigating the most prevalent of combs is going to have the biggest across-the-board impact on CW searches. These combs are listed in the summary section above.

1. Betsy and Travis scrutinized the beam position on SRM and SR2.

After they're done, to me the beam position on the back baffle hole of SRM seems to have moved further to -X direction by a mm or two but the beam was moving and we weren't sure.

2. At this point the rejected beam from OFI cleared the rotator.

Good.

The beam cleared the OFI rotator and was going to the direction of ZM2. The beam spot on two steering mirrors on OFI were to the +X direction. Since Koji didn't want to move the mirror base plate position while he was here, we only turned the mirror holder to center the beam on the second mirror (the first mirror is still off centered but it's far enough from the edge).

TJ installed the ZM2 on the new riser and put it roughly at where it should be, so we aligned the second steering mirror on the OFI to roughly center the beam on ZM2. TJ also installed the beam dump with the right post.

Gerardo needs to confirm the OFI alignment relative to the beam again.

3. Septum window was rotated 180 degrees.

The scribe mark showing the thickest side is now at 9 o'clock position (i.e. +X).

Yesterday the beam was at X=-36mm on OM1, I expected that the septum rotation will bring the beam to -9mm position (alog 39491). In reality the beam was at -13mm position. At least the movement in the correct direction, height is still correct.

Without doing anything, the beam was already hitting OM2 though too low. Attached shows some measurement numbers we made.

4. What needs to be done for HAM6.

VOPO path:

This needs to be done before corner pump down. Irises need to be installed. ZM2 and OFI steering mirror on HAM5 needs to be adjusted to center the rejected beam on irises on HAM6.

In principle the following could be done after the corner pump down with the IMC locked, but we should convince ourselves that this will absolutely work.

OMC path:

To make sure that no part of the beam comes too close to any of the edges, unfortunately OM2 needs to be moved to +X direction, meaning OM3 needs to be rotated.

OM1 is pushed to -X by 13mm, rotated to send the beam to the center of new OM2 location (and rebalanced as the beam is too low on OM2).

OM2 is pushed to +X by 19mm or so, this will increase the distance between the OM1-OM2 line and the edge of the OM3 by 10mm-ish. OM2 also needs to be rebalanced as the angle of the beam coming from OM1 will be different.

OM3 is rotated to accommodate the beam angle change.

I and Sheila convinced ourselves that this will work though painful.

ASC-AS_C path:

Everything could be moved to -X by 13mm or so and it will be fine.

I and Sheila convinced ourselves that this will work.

OMC REFL path:

Beam diverter will be reused for SQZ path, OMC REFL QPD sled wasn't used and probably will not be used, so most of this path could be replaced by a single high power beam dump?

OMC TRANS path:

No need to do anything?

(Travis S, Gerardo M)

This time septum viewport was rotated 180 degrees, it's fiducial line is now pointing towards 3 O'Clock.  Bolts aren't torqued yet, this will allow for the installation of a bracket for an accelerometer in the coming days.

Following on from Keita's alog from yesterday, we spent all day attempting to convince ourselves that the SR chain of optics are hanging symmetrically within their structures, using little to no tooling.  Holding rulers up to various optics and structures, and painstakingly logging measurements, I could not find any reason to believe that the beam centering we've done between the center of SR2 and SRM is out by more than ~2mm.  The PSL beam line that we have set between the center of SR2 and SRM looks good to carry on.  Indeed, this may mean that the baffles do not look symmetric on the structures, but at least the beam path appears correct.  We'll revisit baffle positions an drawings tomorrow.

Meanwhile, since I was wandering the tube between HAM4 and HAM5, I took a look at the beam centering going through the newly built SR2 scraper baffle D1003300.  At first I was thrown off by the fact that the beam seemed to go through the baffle off center even though the baffle was installed using a template which I would have thought set it pretty close (within mm's).  A lunch break consult with Keita and Calum pointed out that the beam I was looking at was only the SR3-to-SR2 beam which straddles the centerline of the baffle ellipse hole with the SR2-to-SRM beam which is hard to spot when viewing the SR3-to-SR2 beam with an IR card.  A quick calculation, and a SW confirmation told us the 2 beams should be separated by 20mm and should straddle the centerline.   Now how to find the center of the hole while standing in the dark with a viewer card and not occulting the beam with your body...  I gave up trying to measure in-situ and instead opted for some pictures to scale.

Attached is the PDF scaled pic I used - I'm not spending any more time screwing around with the oddities of why the font is miniscule - what I did was:

- Scale the aperture in the picture to the 161mm dimension I read off the drawing D1003301 (for what ever reason Adobe makes starts the scale at a huge setting like some 40 inches or so)

- Using the new scaler, measure to the beam center shown in the picture

- 161mm /2 = 80.5mm is where the center of the aperture should be, so the beam center should be left of that by 10mm (half of the 20mm), 90mm.

- The beam is at 87.4mm.  Of course it's hard to estimate the beam center since the beam is ~20-30mm in diameter, fuzzy, and moves a bit.  I'd estimate the error of my ability to measure this centering to better than 5mm...  Feel free to redo.

Seriously, please let that be close enough.

I did however, take a picture of what can be seen from the plane of the MCTube Eyeball baffle closest to HAM4 on the beam path (see below).  Not sure I was able to place the camera on the beam line very well...  I can confirm that everything shown in the left lobe cutout of the baffle is in dead all HWS silver mirror reflections (and no metal from mounts).  It's hard to tell if there is a sliver of the right side of the SR2 optic still in the right portion of the right aperture lobe.  Maybe it's the angle of my camera view.  Dunno.

Richard M, Dave B, Fil C, Peter K, Marc P.

WP7226

This morning we completed an investigation of the Bullseye PD signal chain.  It was determined that the ISC250 cable position in AA Chassis S1102766 was incorrectly placed one space to the left and should be attached to (IN 29-32).  This was likely overlooked when these chassis were rearranged to make space for squeezer electronics on November 2nd, .  The cable was moved to the correct position and we verified that the signals are received by the ADC.

This morning I completed the weekly PSL FAMIS tasks.

HPO Pump Diode Current Adjust (FAMIS 8449)

With the ISS OFF, I adjusted the operating current of the HPO DBs.  The changes are summarized in the below table and a screenshot of the PSL Beckhoff main screen is attached for future reference.

This is a large increase for just one week of operation, which can be an indication of a DB nearing the end of its life (remember that DB2, DB3, and DB4 are still the original DBs installed when the H1 PSL was in late 2011/early 2012).  We will keep an eye on this.

I did not adjust the operating temps of the DBs.  The HPO is outputting ~154.0 W and the ISS is back ON.  This completes FAMIS 8449.

PSL Power Watchdog Reset (FAMIS 3920)

I reset both PSL power watchdogs at 17:18 UTC (9:18 PST).  This completes FAMIS 3920.

   Posted below are the 45 day trends for the HEPI pumps. Most plots look reasonable for being in a vent status. The CH6 HPI-PUMP_EX_PS_PRESS signal drops to <0 at 19:02 (11:02PT) on 11/08/2017. This may be due to the HEPI control channels being migrated to Beckhoff.   

(Keita K, Jeff K, Gerardo M)

After centering the beam on SRM the OFI position was way off with respect to the beam, so the cage was moved until the beam made it all the way to HAM6, the beam position is satisfactory on YAW, however the position is off in PITCH at the input of the OFI, fine tuning to continue tomorrow.

1. SRM beam position was off last week by about 3/8 inch.

When the beam is properly centered on SRM, the beam position on SRM is about 3/8" towards -X than we thought last week.

Beam centering on SRM horizontally is almost impossible to do by looking from outside HAM5, and instead it seems as if this was done in the past week by centering on the baffle hole on the back of the SRM.

Today we sent JeffK into the tube between HAM5 and HAM4 and have him look at the beam on SRM while I was holding the card right in front of the SRM. Doing it this way, it turns out that the beam is about 3/8" inch off centered on the back baffle hole in -X direction.

My guess is that the  original centering was not done from the front of the SRM. I also wonder if the cage position itself is off.

TJ repositioned the baffle so the beam is centered on the back baffle, and Gerardo moved OFI such that the beam at least clears the OFI (he'll fine tune tomorrow).

2. Septum window was rotated by 120 degrees counter-clockwise and the beam was great in PIT, but of course not great in YAW.

Gerardo and Travis rotated the septum plate by 120 degrees counter-clockwise so that the beam height becomes good on OM1.

The thickest side went to South, which moved the beam further in -X direction.

The beam was blocked by the fast shutter. When I moved FS to the side, the beam was hitting somewhat to the -X side of OM1 -X damping plate adjuster screw, meaning the height was right but it was off to the side by about 36mm in -X direction.

Table below shows Koji's measurement of beam position on OM1 last week (alog 39460), beam position changes which should have been caused by septum rotation assuming that the wedge angle is 0.89 deg (measured by Koji, instead of 0.75 deg derived from the thickness measurement) (alog 13399), and the beam position measured today. If everything is right "in theory" and "measured" columns should agree. At least they don't look totally wrong.

3. Rotating Septum by 180 degrees will bring the beam to a better position

Assuming that SRM is/was at the correct location (we need to check), the next question is what to do.

Unfortunately, I cannot simply move OM1 and be done with that, it seems like the beam from OM1 to OM2 will be either blocked by OM3 or very close to it. I can move OM2 but that will leave no room for the fast shutter as the OM1-OM2 will be much closer to OM2-OM3 line than before.

We can rotate the septum window by 180 degrees so the thickest side comes to the north. Assuming 0.89 deg wedge, the beam deflection is 7 mrad, so 180 deg rotation will give us 14mrad change in deflection.

The distance from the septum to OM1 is 1930mm, so this will result in the horizontal shift of 27mm  without height change. The beam will be at X=-36+27 = -9mm on OM1 horizontally. Hopefully this will allow us to make room for the fast shutter without moving OM2 sideways.

Laser Status:
SysStat is good
Front End Power is 35.8W (should be around 30 W)
HPO Output Power is 151.5W
Front End Watch is GREEN
HPO Watch is GREEN

PMC:
It has been locked 2 days, 7 hr 43 minutes (should be days/weeks)
Reflected power = 25.37Watts
Transmitted power = 48.21Watts
PowerSum = 73.58Watts.

FSS:
It has been locked for 2 days 7 hr and 43 min (should be days/weeks)
TPD[V] = 2.039V (min 0.9V)

ISS:
The diffracted power is around 1.6% (should be 3-5%)
Last saturation event was 2 days 7 hours and 43 minutes ago (should be days/weeks)

Possible Issues:
PMC reflected power is high
ISS diffracted power is Low

Jeff B and Dave:

Jeff inherited a very red looking CDS overview screen this morning (see attached) which was not being auto-cleared.

Digging deeper, the h1lsc0 user models TIME glitched at 06:56 PST this morning, but the h1ioplsc0 model did not. This is the first time this has happened, the normal glitch behaviour is an IOP glitch with optionally an accompanying user model glitch. My auto-diag-reset script only looks for LSC-IOP glitches, and therefore did not clear this one.

If we see an overview similar to the attached one, please alog it and then press the "! Diag Reset" button on the bottom of the CDS overview screen to clear the errors.

[Maddie W., Aaron V., Greg M.]

Here is a summary of the filters and command line arguments that should be used for the C02 frame generation using the DCS calibration pipeline.  This information is compiled from configurations wiki page and aLOGs linked from that wiki page.  The command line arguments should be the same as for C01 except for changes noted in the table below.  (Additionally, the frame names and channel names should be changed appropriately to C02.)

--expected-fcc=347.2
--coherence-uncertainty-threshold=0.004
--wings=(something larger than 600)
--no-fs 
--no-srcQ
--update-fcc
--fcc-averaging-time=600
--fcc-filter-taper-length=32768
--pcal-channel-name CAL-PCALY_TX_PD_OUT_DQ

--expected-fcc=360.0
--coherence-uncertainty-threshold=0.004
--wings=(something larger than 600)
--no-fs
--no-srcQ
--update-fcc
--fcc-averaging-time=600
--fcc-filter-taper-length=32768
--pcal-channel-name CAL-PCALY_TX_PD_OUT_DQ

--expected-fcc=360.0
--coherence-uncertainty-threshold=0.004 
--wings=(something larger than 600)
--update-fcc
--fcc-averaging-time=600
--fcc-filter-taper-length=32768
--pcal-channel-name CAL-PCALY_TX_PD_OUT_DQ