TITLE: 04/27 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:
To continue the ASC input matrix stability testing from last night, I restored the AS_A / AS_B RF36 WFS combinations we were using (-1 / 1 for PIT, and -0.8 / 0.5 for YAW). Apparently these haven't made it into the guardian yet. Ramping them on by hand appeared to improve the alignment. I also enabled a length dither, which we plan to use to monitor the DARM pole (LSC-OUTPUT_MTRX_1_9 set to 1). Leaving H1 locked in this state overnight.
DIAG_MAIN notification shows that HWSX had bad peak counts for a moment. Timeseries shows that this happened between 4:10 and 4:13 UTC but got better on its own. The glitches is probably caused by me stopping and restarting the code to look at stream images. They look fine. The output power off HWSX sled is ~0.8W.
I think you mean 0.8mW
Oops yes. Sorry.
Chris, Keita, Evan
Today we were able to lock the outer ISS loop with the modecleaner at 20 W (and no interferometer). We looked at several PSL/IOO PD signals (the FSS transmission PD, the ISS inner-loop PDs, the IM4 transmission PD, and the ISS outer-loop PDs) and tried to understand their behavior in different ISS configurations.
Naively one would expect all these signals (except the in-loop ISS PDs) to agree with each other, since they should all be out-of-loop sensors for the RIN leaving the PMC. Together, these signals monitor three of the four PMC ports: the FSS transmission sees the RIN of one port, the out-of-loop inner-loop ISS PD sees the RIN of another port, and IM4 trans and the out-of-loop outer-loop ISS PD sees the RIN of yet another port.
These are the behaviors we observed (see attached pdf):
We think that a possible explanation for these effects is that both ISS PDs are seeing some correlated noise that is not seen by either the FSS PD or the post-IMC PDs. In this scenario, the inner-loop ISS would suppress the HPO noise but impress this correlated noise on the light entering the PMC.
Briefly we entertained the idea that the light circulating in the PMC could be multimoded (either from the NPRO or the HPO), but judging from the RIN before and after the IMC, this seems to not be the case (png attachment).
One other idea is that some of the 808 nm light is getting through the PMC and onto the ISS.
Is this really incompatible with jitter? There are a lot of variations visible on the PMC reflected camera. The finesse of the PMC isn't that great (~100), and neither is jitter supression. If there is a static misalignment into the PMC, there would also be a linear term for the jitter to intensity conversion. The two inner loop detectors see rather different signals at 10Hz, if the inner loop is engaged but not the outer one.
Certainly the jitter seen on the IMC WFS is worse than before the HPO turn-on.
Before the turn-on, the jitter below 100 Hz was 1 nrad/Hz1/2 or so (LHO#21212). Now it is 10 nrad/Hz1/2 at 10 Hz, with a 1/f slope.
The attachment shows IMC signals with the inner ISS loop off (dashed) and on (solid).
Update: BS alert. Read the next entry.
Jitter is much larger than before, but the jitter alone doesn't seem to explain all of our observations at the same time when the 1st loop is closed but the 2nd loop open.
PDA=P+a*J+Sa, PDB=P+b*J+Sb, IM4=P+x*c*J+Sim4
P is the intensity noise leaving the AOM. When the loop is open it's just the free running noise P0.
J is the beam jitter (01 amplitude relative to 00) coming out of PMC.
a, b and c are the jitter to intensity coupling at PDA, PDB and IM4 trans due to clipping or diode inhomogeneity or whatever.
x is the attenuation of 01 mode amplitude by IMC, which is about 0.3%.
Sa, Sb and Sim4 are the sensing noise.
When 1st loop is closed, J is imprinted on P:
P=P0/(1+G) - G/(1+G) *(b*J + Sb) ~ P0/G - b*J - Sb,
PDA ~ P0/G + (a-b)*J +Sa-Sb,
IM4 ~ P0/G + (x*c-b)*J + Sim4-Sb ~ P0/G -b*J +Sim4-Sb. (note x=3E-3.)
where G is the OLTF.
Allowing some conspiracies but not extreme ones, lack of coherence between PDA and IM4 is explained in either of the following:
The first case is false because swapping PDA and PDB makes no difference in IM4.
In the second case, PDA spectrum should look like all sensing noise, but this "sensing" noise in reality is big at 10Hz.
So, even if the clipping effect is common in PDA and PDB so the PDA and IM4 becomes incoherent, we need another noise that is not unlike big sensing noise, i.e. of about the same amplitude on PDA and PDB, is incoherent between PDA and PDB, and does not appear on downstream sensors.
I take my words back about PDA-downstream coherence.
I was looking at the coherences from this morning, and it seems like when only the first loop is on, 1st loop out of loop sensor is coherent with downstream sensor before and after the IMC (attached, bottom red and blue). The plot is calibrated in RIN.
Note that we switched the control photodiode from PDB to PDA last night, so in this plot the out of loop sensor is PDB. I switched them back again at 17:49:10 UTC.
Anyway, out of loop sensor is more coherent with downstream sensors than HPL monitor is at f<10Hz (bottom red|blue VS brown|pink), but HPL is more coherent from 10 to 200 Hz. Difference between bottom brown and bottom pink probably doesn't mean much, just the noise floor difference between IMC-PWR and MC2_TRANS.
Some thinking necessary, but at the moment I cannot say that jitter cannot explain everything.
John and I visited CP5 before lunch today to investigate why the liquid level is so noisy (compared to CP6). We verified wires were tight at the controls rack, and eventually made our way to the LL transducer. We closed the exhaust at transducer and the flow stabilized suggesting the instability is caused by a real pressure differential and not electric. We did not check the LLCV pneumatic actuator. After trending the numbers this evening, looks like we did a real number on the system. See plots attached. The % valve open is ranging full scale and LL full spans 90-95%.
Could this be related to the midstation air compressor replacement?
Richard just reset the PID values (same values). The LL seems to have stabilized (well, to its prior stability which is still relatively noisy). We will watch it throughout the day.
Per https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=26797 Set valve 25% open in manual mode. It currently reads 94% full. Tomorrow we will transition to PID.
Gerardo, Kyle We torqued BSC4's dome bolts and found many that were very loose. We then valved-out the pump cart and the ion pump responded by temporarily "railing" but has since come on-scale on its own - i.e. we fixed the outer O-ring leak -> The pump cart was then shut down (this pump cart has been running near the SW corner of BSC4 for the past few weeks and shutting it off, finally, is "very exciting" for us!). During this process, it looks as if the signal cable to the Diagonal Volume's pressure gauge-pair, PT140, was disturbed resulting in an anomalous reading from the Pirani gauge. This then tripped off the Cold Cathode gauge -> We were able to "wiggle" the cable etc. and get them to resume normal readings. Additionally, we determined that HAM11's ion pump needs to be replaced but are electing not to replace it as HAM12's ion pump can keep the combined HAM annulus volumes at adequate vacuum for the time being. Currently there are two pump carts running in the LVEA by HAM11 and HAM12, these will be shut down in the next day or two.
Yesterday (Monday 25th April) the MY vacuum controls system was upgraded to Beckhoff. Today (Tuesday 26th April) both LVEA systems (LX and LY) were upgraded to Beckhoff. I have performed the following on all three systems:
* = in the new system CP pump levels cannot exceed 100%, therefore I reduced the HIGH ALARM limit from 100% to 99%
still to do:
I updated the control room alarm handler.
Reset ITMX.
15:02 UTC Peter to H1 PSL enclosure 15:06 UTC Turned off BRS sensor correction at end X and end Y for Karen to enter the VEA to clean 15:19 UTC Gerardo shimming CP1 LLCV and CP2 LLCV in preparation for Beckhoff vacuum controls upgrade 15:23 UTC Filiberto taking tools to LVEA for Beckhoff vacuum controls upgrade 15:27 UTC Joe to LVEA to charge batteries 15:27 UTC Jeff K. starting charge measurements on ETMX and ETMY 15:30 UTC Bubba and Nicole to LVEA 15:33 UTC Sprague through gate 15:33 UTC Richard to LVEA to work with Filiberto 15:33 UTC Betsy and Travis to LVEA and optics lab 15:42 UTC Ed to LVEA to work with Richard and Filiberto 15:59 UTC Joe out of LVEA, taking Sprague to mid and end stations 16:05 UTC Carlos working on DMT network 16:12 UTC LN2 delivery through gate 16:12 UTC Karen out of end X, getting shoe covers from corner station 16:34 UTC Karen done dropping off shoe covers at end X, going to end Y 16:39 UTC Beckhoff vacuum controls upgrade done at LY 16:46 UTC John and Chandra to mid X to look at signals 16:47 UTC Hugh to end stations to check HEPI fluid levels 16:54 UTC Jeff K. done charge measurements 16:56 UTC Joe back from escorting Sprague 17:19 UTC Kyle to end Y to record number for property audit 17:21 UTC Gerardo to BSC4 to tighten bolts around dome 17:22 UTC Paradise water delivery 17:24 UTC Karen and Chris done at end Y 17:30 UTC Ryan done WP 5831 (internet back) 17:37 UTC Kyle back from end Y Richard and Filiberto starting Beckhoff vacuum controls upgrade at LX 17:56 UTC John and Chandra back from mid X 17:59 UTC Keita escorting film crew to X arm mid point beam tube tunnel 18:03 UTC DAQ restart for LX and LY Beckhoff vacuum control channels 18:10 UTC Joe to LVEA 18:15 UTC Jim W. taking ETMY ISI and HEPI down for measurements 18:28 UTC Joe back 18:44 UTC Keita done from escorting film crew 18:45 UTC Gerardo done at BSC4 18:46 UTC Vending machine delivery 19:42 UTC Filiberto to LVEA to work on dust monitor wiring 19:42 UTC Carlos done 20:28 UTC Richard to look at CP1 20:29 UTC Filiberto done with dust monitor work, going to beer garden to see what is needed for cabling PT170 and PT180 BPG402 gauges to Beckhoff vacuum controls 20:35 UTC Bubba replacing mid X instrument air compressor 20:36 UTC Peter done in H1 PSL enclosure 20:45 UTC Travis to LVEA drop off bins and parts 20:59 UTC Travis back 21:23 UTC Filiberto to LVEA to setup for pulling cable 21:45 UTC Filiberto pulling cable from LX vacuum rack to beer garden 21:58 UTC Jeff B. to LVEA to work on dust monitor wiring 23:18 UTC Filiberto done
TITLE: 04/26 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: Patrick
CURRENT ENVIRONMENT:
Wind: 16mph Gusts, 8mph 5min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.22 μm/s
QUICK SUMMARY: Maintenance Day. Commissioners have the IFO currently.
Attached are some data traces from today's work on the power stabilisation. After tweaking the alignment of the ISS AOM, I found that the maximum diffracted power in the first order was 4.1 W when the offset slider was at 10%. aomfreqinput.png shows the 80 MHz into the AOM as things were - a 9 dB attenuator was in the path. 0.28 Vrms corresponds to about 1.6 mW. The AOM driver input should be around 6 dBm. aom[5-7].png show the AOM driver input with 5-7 dB attenuators respectively. A 5 dB attenuator was left installed. The 0.45 Vrms corresponds to ~6 dBm. The resulting diffracted light is shown in DiffPwr.jpg. This hopefully will solve the saturation issues observed earlier. rpn2.jpg shows the output of PDA and PDB. PDB being the one used as the sensor for the loop. The agreement between PDA and PDB is okay for the free-running spectra. With the loop closed, the agreement is not so good below 3 kHz. Increasing the servo gain, increased the noise beyond ~10 kHz. AOMControl.png is the spectrum of the drive voltage to the AOM when the servo was locked to yield the above noise measurement. ISSTF2.jpg is the transfer function measurement. UGF is ~58 kHz with a phase margin of ~25 degrees. Obviously plenty of work to do in order track down the source of the excess noise. Hopefully the power stabilisation will not be so fickle.
I changed out instrument air compressor #2 at M X today.
Today we completed the installation of the Beckhoff Vacuum System upgrade. The last two chassis installed were LX and LY. One hiccup was a blown fuse on the Fill control valve on CP-1. This was most likely caused when working on the Watchdog circuit the connects to the 24V supply for this valve. This caused an overfill of the pump. May have to leave in manual fill or control at 99% for the night. Next step will be to add the new Inficon 402 gauges PT170 and PT180 and annulus Ion Pumps .
Jeff B., Patrick T. h0dust is the virtual machine that Cyrus created to run the software for the Lighthouse dust monitors in the H1 PSL enclosure: https://lhocds.ligo-wa.caltech.edu/wiki/h0dust I connected to h0dust over VNC. I closed the two EPICS IOCs. I stopped the dust monitors (which are not actually connected) and disabled the network connections in LMS Express. I closed LMS Express. I shutdown Windows.
Rich and I are trying to figure out what we can use the BRS for more than tilt subtraction of the ground seismometer. Today, we looked at coherence between the BRS and ISI rotational dofs and it doesn't look promising. To check this, we took the chamber to offline, so we could compare the ground rotation seen by the ISI to the motion measured by the BRS. The first plot shows the coherence between the BRS and the ISI, and, sadly, there doesn't seem to be any in RX. Brown and pink are the coherence to the ISI's T240RX and CPSRX, light blue is the T240Y to the BRS RX. The next plot shows what is working well, the tilt subtration from the Y ground STS. Red is the coherence between the BRS and the corrected STS signal, blue is the coherence between the BRS and the uncorrected STS signal, below .1hz the coherence pretty much disappears on the corrected signal until about 10mhz where the subtraction makes the STS signal worse, which we expect. The last attached plot shows the different spectra, calibrated into rad or m, as appropriate. Not a whole else to add, other than the wind was moderate (~10mph) during this measurement, so we probably should expect more coherence with higher winds. Friday looks like a more "promising" forecast, with respect to winds.
J. Kissel, B. Weaver, T. Shaffer I've - measured a new charge data point for 2016-04-26. - processed all measurements that had not been processed over the past few months of measurements - fixed the NDS problems that Betsy and TJ had been having preventing them from plotting the trend of the effective bias voltage As such, it has now become blatantly obvious that between the last time we intentionally flipped the bias voltage on both ESDs in order to mitigate charge accumulation (on Feb 15th; see LHO aLOG 25575) both ETM ESDs have had their settings reverted within a month of the flip, and are now continuing to charge in the wrong direction. Further, it looks like the ETMY ESD bias voltage was reduced by half (albiet still on the wrong direction) somewhat recently on Apr 14th. What's even more worrisome is that neither the ETMY LOCK gain nor DRIVALIGN gain -- which should be used to compensate for the strength change resulting from a reduced bias -- were changed when it was reduced. At least, it appears as though that as we've been commissioning ASC stuff for the past month or so, we haven't been transitioning to ETMY anyways, so it may not have mattered (*phew*) and also why it has gone relatively unnoticed. As such, we should re-flip the bias sign on both ETMs, to what we flipped them to on February and I recommend with flip EY back to the larger value of bias voltage, so that the opposing sign of charge accumulates and the net charge decays back towards zero faster. I've done a good bit of aLOG, snap file time-stamp, and EPICs records sleuthing and have conclude that the flips were unintentional settings loss, as a result of us having SAFE, DOWN and OBSERVE.snap files in concert with several h1susetm[x,y] model restarts that were unplanned or after-thoughts (namely the HWWD install LHO aLOG 25860; and PI model install LHO aLOG 26200). No one is to blame here, it's just a testament to how hard it is to track and control settings during heavy commissioning, especially when we need to make a decision on how many of the three of the SDF files need updating. Kiwamu concisely summarizes the steps to flipping the bias in LHO aLOG 25575, and we'll work with the commissioning team to do so as soon as conceivably possible. However, what Kiwamu failed to mention is that we need to update the H1SUSETMX, H1SUSETMY, and H1CALCS SDF snap files, and do so in the SAFE, DOWN, and OBSERVE snap files. Attached are the charge trends and a zoom of when the EY bias was reduced on Apr 14th.
