J. Kissel

Grabbed a few closeout measurements of H1 SUS OMC. All clear; good to go for door closure.

Transfer functions show that the dynamics are virtually identical to what they were before. See 
    - Individual measurement 2018-04-25_2324_H1SUSOMC_M1_ALL_TFs.pdf 
    - Comparison with others allomcss_2018-04-25_2324_H1SUSOMC_M1_Phase3a_ALL_ZOOMED_TFs.pdf 

High Frequency OSEM sensor noise ASD,
    - 2018-04-26_1831_H1SUSOMC_M1_OSEM_Noise_ASDs.png
has some spikes, but nothing egregious like a grounded BOSEM (e.g. LHO aLOG 40787). If I had to complain, I would complain about the T1 OSEM being a little higher in noise starting around 500 Hz. But I don't have to complain, so I won't. #WORKSFORME

TF Data Templates 
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_L_0p02to50Hz.xml
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_P_0p02to50Hz.xml
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_R_0p02to50Hz.xml
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_T_0p02to50Hz.xml
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_V_0p02to50Hz.xml
    2018-04-25_2324_H1SUSOMC_M1_WhiteNoise_Y_0p02to50Hz.xml

ASD Template 
    2018-04-26_1831_H1SUSOMC_M1_OSEM_ASDs.xml

I'm bypassing LX alarms to cell phones while the IOC is being worked on. Alarm bypass will expire 15:28 PDT.

As part of the HAM6 closeout and prep for pumping, I have disabled the picomotor drivers for HAM6/ISCT6 as well as Squeezer (those are the labels on the picomotor screen).  All other picomotor drivers were already disabled.

TVo, Sheila, Dan Brown

Summary: Astigmatism in the OPO beam (that seems to be happening in HAM5 somewhere) is limiting the mode matching to the OMC. If the astigmatism can be fixed we could get 95% or better matching.

Along with the OMC mode scans taken the other night we also took beam profile measurement in HAM6 with the Nanoscan. On the OMC side of the table we took profile between HAM5 and OM1, OM1 and OM2, and on OMC REFL, on the OPO side we took them after ZM1 and the propagated off of the beam diverter onto SQZT6. Using the as built Finesse model for the HAM5 to OMC path I fit the input x and y plane beam parameters to the data. This is compared to the as built OMC mode propagated to the SRM AR surface (beam parameter values in the legend). 

The x-plane beam has an overlap of 83%, the y-plane 95%. Taking the ratio of the 2nd to 0th order peaks in the OMC scan will average the two planes, so we measure 89% matching. Which agrees pretty well with what we measured the other night. Although the OMC scan ratio should underestimate the mismatch in general due to astigmatism in the OMC, the non-zero 1st order peak from misalignment also couples a bit into the 2nd order modes, which causes an overestimate in the mismatch as it makes 02/20 larger. These two effects just happen to cancel each other out in these scans it seems.

I also compared our measurements to what I originally predicted we should have got. As can be seen the y prediction vs fit isn't that far off, but the x-plane astigmatism is causing it to be significantly different.

Lastly, I fit the beam profiles to a mode propagating away from ZM1. If there were no astigmatism (and the model parameters are correct) this beam propagated to the OMC would have ~98% matching.

BRS-X excursion is due to clean-rooms and work being done at the location. BRS-Y needs to be addressed. This downward trend is typical.

TITLE: 04/26 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 5mph Gusts, 3mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.18 μm/s
QUICK SUMMARY:

All Quiet on the Hanford Front.

I have locked PRX using the ALIGN_IFO guardian node, after a bit of alignment tweaking by hand.  In particular, ITMX is quite far from where it was.  PRX is not yet aligned well, since I got distracted trying to close the REFL DC centering loops (which are now closed). 

Next up:

• Rephase RF PDs, both LSC_REFL and REFL WFS. 
• Measure REFL DC centering loop OLGs, especially DC2 for REFL_B.
• Engage WFS loops, and hopefully be able to have them track the alignment change as ITMX is brought back closer to the alignment that has been in use for the last week or so.

I think there are some sign flip shenanigans going on, which I think that I have fixed and they make sense now. But, the DC2 centering loops are still unstable for their old nominal gains.  Right now the gains are lower by a factor of 4 - increasing them causes the loops to go unstable.

Recall that in alog 40853 JeffK flipped some signs so that the suspensions were matching the proper sign conventions.  TVo, Sheila, and others found that this meant they needed to flip the feedback signs in the AS DC centering loops, as noted in alog 41436.  In that alog, Sheila preemptively flipped the signs also in the REFL DC centering loops.  However, as Jeff noted in his alog, RM2 didn't need the sign flip that the other *Ms did.  So, just flipping the DC centering loop sign isn't quite the right thing.  In the end, I put the REFL DC centering loops back to their previously nominal negative signs, and then flipped the sign of the RM1 elements in the ASC pitch and yaw output matrices, leaving the RM2 elements alone.  I think this achieves the correct sign-flippage.  But, the DC2 loops are still unstable when I go to their full gains (-10 for pit and -12 for yaw).  So, for now they're set at -3 for both pitch and yaw.  Tomorrow I'll measure the loops and see what's going on.

Attached is the alignment slider screenshot of where I have things right now.

Related entries:

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=29416

https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=6446

Summary:
For a very long time we've been limping along with some of the TMSX BOSEMs (namely F1, LF and RT) somehow seemingly less sensitive than they used to be (see the above alog and FRS).

By merely pushing BOSEMs closer to the magnets using adjustment nuts and roughly setting them to half the open value, the response of these BOSEMs were restored.

We also changed RT BOSEM (SN 164) to the one Betsy gave us (SN 083) because we could, but it was unnecessary in a retrospect. We won't change it back because it's a pain.

Details:

We measured the OSEMINF_INMON for suspected ones fully open by pulling BOSEMs away from the mass using adjustment nuts. (In the case of RT we removed the BOSEM plate from the cage and didn't see a large change.)

We found that all of them were already very close to the open values, and that open values were smaller than they used to be judging from the offsets that were set a long time ago. The former means that BOSEM bodies are much farther away from the magnets than they used to be. Apparently TMSX sagged and rolled.

We swapped RT (SN 164) with the known good one (SN 083). No particular reason for the choice of RT rather than LF, it's just that Corey was working on RT at that time and thus was convenient to test.

We set the offsets to half the corresponding open count, and adjusted the BOSEM depth so that they come close to the offset.

The attachment shows the coil to coil transfer coefficient (OSEMINF/COILOUTF_EXC) at about 0.02 Hz before/after the change for F1, LF and RT (it also shows F2 and F3 but there's no "after" for these). You want to compare pink open circle with red solid disk, or blue open triangle with blue solid triangle.

As you can see the sensitivity increased by a factor of 1.9 for F1, 2.75 for LF and 3.3 for RT.

As for RT, a factor of 1.2 came from the increase in the LED power (26.95k/22.1k=1.22), so the change caused by the depth of OSEM is 3.3/1.2=2.8, almost the same as LF.

I removed a factor of 3 that was added to the PIT damping gain at some point, now all damping gains are 1 (except SD).

I'm also somewhat worried about TMSY LF and RT just because the OSEMINF_INMON is much larger than the offset (second attachment). However, similar measurement for TMSY (third attachment, left half is TMSX, right half is TMSY), it doesn't look as if F3 and LF are terrible.

Thomas Vo, Sheila, TJ, Nutsinee

This morning Thomas TJ and I set the alignments of the OMs back to the alignments we found using the single bounce beam (41540), and steered the seed beam on to the AS WFS.  This meant that ZM1 was almost railed, as we had seen yesterday, so we moved it in yaw.  We were then able to center on the AS WFS for a couple of different pico alignments. 

We decided that this is the last thing we need to do in HAM6 for the squeezer before putting doors on, so after lunch Nutsinee TVo and I went back and removed our apertures and tools, wiped the table surfaces off, used the flashlight array to look at the VIP and other optics (didn't see any real problems), and Nutsinee took many photos.  We also spent some time clearing some of our equipment out of the area in preparation for moving the tables tomorrow.  Nutsinee checked that everything is secured inside both SQZT6 and ISCT6, so after removing the cables and carefully stowing the fibers we should be ready to move the tables tomorrow. 

Daniel, Nutsinee

Last week we went out to SQZT6 with a halogen light bulb and measured shotnoise of the OPO refl PD (aLIGO broadband PD). An input of 0.5mA (0.7V/1400 Ohms transimpedance) gives ~200nVrms/sqrt(Hz). Using a responsivity of 0.3 A/W I calculated what shotnoise would be like for a green input power of 7mW (right below threshold power of 7.4-8mW, see alog41150 for details) and 3.5 mW (~half the threshold power, possible operating point according to Sheila). At 7mW input to the OPO, 6.02 mW is expected to hit the PD (14% loss between fiber and SQZT6, see alog41623)  we expect about 40% coming back when we're locked (alog41045)  and we are about 2 orders of magnitude about a factor of 2 above dark noise at this operating power. At half power we are just a factor of 1.2 above the dark noise. The shotnoise limited power is about 1mW.

Note: OPO locking signal comes from this PD.

We also measured shotnoise of the homodyne. More alog to come.

Have yet to test to see if everything still work with these new cables. Just wanted them in before the table is moved.

TITLE: 04/25 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

LOG:

14:59 (7:59) Ken to various parts of CS -- Installing cameras

15:00 (8:00) Start of shift

16:00 (9:00) Sheila to HAM6 -- Split cover

16:01 (9:01) Hugh, Corey to LVEA -- Mark table location, lock HAM4 HEPI

16:05 (9:05) Chandra to MY

16:15 (9:15) Sheila back from HAM6

16:49 (9:49) Nutsinee to SQZ rack -- Plugging in cables

17:03 (10:03) Nutsinee back from SQZ rack

17:06 (10:06) Sheila to LVEA -- take lock off PSL light pipe

17:07 (10:07) Cheryl to LVEA

17:08 (10:08) Corey back from LVEA

17:08 (10:08) Hugh back from LVEA

17:10 (10:10) Sheila back from LVEA

17:15 (10:15) Cheryl back from LVEA

17:27 (10:27) Chandra back from MY

17:34 (10:34) Keita, Corey to EX -- TMSX work

17:40 (10:40) Peter to PSL enclosure

17:48 (10:48) Hugh to HAM4 -- finish lockup

17:59 (10:59) Sheila, TJ, TVo to HAM6 -- check SQZ/IFO beam alignments

18:20 (11:20) Hugh back from HAM4

18:37 (11:37) Rick to PSL enclosure

18:41 (11:41) Ken to LVEA

19:08 (12:08) Corey, Keita heading back from EX for lunch

19:20 (12:20) TJ, TVo,Sheila back from HAM6

20:09 (13:09) Peter, Rick out of PSL enclosure

20:10 (13:10) Keita, Corey to EX

20:20 (13:20) Ed to SQZ table -- Label connectors

20:48 (13:48) Sheila, TVo to HAM6 -- Take close-out photos

20:50 (13:50) Nutsinee to HAM6 -- assist Sheila and TVo

21:05 (14:05) Gerardo to HAM6

21:22 (14:22) Chandra to EY, MY

21:46 (14:46) TJ to Optics Lab

21:50 (14:50) Travis to EX -- Deliver BOSEMS

21:53 (14:53) TJ out of Optics Lab

22:00 (15:00) Gerardo back from LVEA

22:10 (15:10) Travis back from EX

22:19 (15:19) TVo, Sheila back from HAM6

22:32 (15:32) Nutsinee back from HAM6

22:35 (15:35) Corey, Keita back from EX

23:00 (16:00) End of shift

After rephasing the IMC RF stuff (alog 41669), I did a quick A2L to see where the spots are.

The most recent measurements, from before the EOM and PMC swaps, are in alog 40422 (I'm using the A2L coeff from that alog, and recalculating the positions, so that the sign convention is consistent on my table here).  The method is from alog 31402.

Overall, we do see some shift, but it's not gigantic except for the short arm between MC1 and MC3 in yaw.

Sheila pointed out that she and Craig had rephased the IMC (alog 41432) after the EOM swap, but hadn't rephased the WFS.  I calculated that the extra 7 ns delay that was added corresponds to about 60 degrees of extra phase delay for 21.4 MHz.  So, for each quadrant of the IMC WFS A and B I subtracted 60 deg.  Allowing the WFS to work after the phasing is noticeably improving the IMC alignment from where the WFS with the wrong phasing had pulled it. 

Note to self:

wavelength of RF = c/freq

length equivalent of extra delay = c*time

ratio of new delay to one full wavelength = freq*time    (c has divided out, so you don't need the precise velocity factor to know the speed of light in a cable)

degrees delay = 360 * freq * delayTime

DaveB & HughR

Spotted continual saturations on the HAM45 SEI IOP and was traced to the subj sensor.  The saturations don't show on the ISI ADC monitor since the first encountered part in the model is not an epics widget; hey hey pretty smart eh!  Pays to hang out with DaveB!

Sure enough this led us to find the Corner 3 L4C Pressure way out of norm.  Fortunately, maybe, the numbers are not an indication of the Pod leaking but of the electronics going south.  That is, if you believe the numbers etc, the pressure in the pod has increased, alot.  If the pod (in vacuum) were to start leaking, the pressure inside, nominally at atmosphere, would decrease.

There are no alarms on these channels, you know, operators hate alarms, and the channel has been in this state since 12 April.  This was after the vent and subsequent pumpdown of the vertex but on the 12th there was activity around HAM5 with viewports looking and leak checking.

The channel also shows a glitch back around early October.  While all the HAM5 pods show a glitch then, it appears this was a power cycle as most direct readings went to zero.  Anyway, sure looks like the L4C Pod is behaving as if in a 'vacuum' as its sisters are not sympathetic.  Trending all the pods (attached is 300 days) shows another glitch in Late October and one might notice that the Corner3 Pod glitches in the opposite direction as its sisters and hits the value were it now remains since the 12 April excursion.  This is also the saturation value:  (124-30)/2.861e-3=32k.  Nominal value at 1 atmosphere ~101kpascals is (101-30)/2.861e-3=~25k which is where all the other ADC inputs for the HAM5 pods are currently.

Will consider some test to determine if this is or is not an in-vacuum problem.

FRS 10499

FAMIS 6947

Reported high frequency noise in ETMX.

The GN2 temp was running low at around 120C. I raised the variac from 60% to 64%. As we run the Dewar dry, we will try to maintain a temperature around 180C. Dewar is currently 43% full, with a ~7%/day consumption. Flow is 40-50 scfhx100. 

I valved out the UHP GN2 from the turbo foreline; foreline pressure is back to 7.1e-3 Torr. 

Spring enabled the EE shop to work on setting up power for the LEMIs, and I had a look at the new signals. The top plot in the figure shows that we can see Schumann Resonances quite well, up to quite close to 60 Hz. The bottom two plots show some transient signals that might interfere with a feed-forward system.

It looks like the signals are degraded by wind. I am not surprised because we see wind noise in buried seismometers. I think we would have this vibration problem even on a perfect flat because of the variation in Bernoulli’s forces associated with gusts. It may be that a LEMI signal is generated by the wind because of slight motions of the magnetometers in the earth’s huge DC magnetic field. We buried the LEMIs about 18 inches deep (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=29096). I think we might be able to mitigate the noise some by going much deeper.  Once we have the vault seismometer working, it would be a good project to test the wind vibration hypothesis by comparing the LEMI and seismic signals.

There also seem to be some transients, some long and some short, possibly self inflicted by our system. It would be good to look into which transients would be a problem, and for those, details such as whether they are correlated with time of day, the average time between transients, etc., in order to help determine their source.

Finally, I would like to get the full system calibrated by comparing to a battery powered fluxgate magnetometer.