Jamie, Kiwamu, Nutsinee

TCS_ITMX(Y)_CO2_PWR nodes are ready to go. We have made the NOMINAL_LOCKED_CO2_LEVEL state dependent of the IFO power. The only thing I have not had a chance to test is the NOMINAL_LOCKED_CO2_LEVEL state at different IFO power (Tested when PSL power = 0 W but I don't see anything that could go wrong). I added two lines of code in DOWN state of the ISC_LOCK guardian to let it tell the TCS nodes where to go but left it commented out (line 415 and 416). Similar for COIL_DRIVERS state (line 2796 and 2797). When ready to commission TCS, make ISC_LOCK manage the TCS nodes and uncomment those lines. The PRE_HEATING power has been set to 0.5 for CO2X and 0.3 for CO2Y according to Aidan's alog.

Matt, Daniel, Patrick, Vern, Kiwamu,

We have spent a day trying to improve the behavior of the PSL rotation stage. Its performance is much better now (the angle accuracy is about several mdeg). We identified two major issues as follows which are now fixed.

• The glitch issue (rotation stage goes backward at the beginnig of  a rotation action for a short period)
• The accuracy issue (accuracy of the terminal angle is only as good as 0.1 deg)

In contrast, we started having a (new) minor issue where occasionally the rotation stage does not exit the busy mode on its own. If this happens a user should manually hit the abort button to terminate the busy state.

[Some details]

First of all, we discovered that the size of the glitch scaled with the size of the error (or the residual) that the previous rotation action has left. This lead us to the conclusion that the accuracy of the rotation stage was not good enough and the PID parameter needed some tuning. In addition, we discovered that the maximum motor velocity was set to a too high value. We were using only a very small fraction of the maximum velocity (0.1 % of the maximum nominally). Ideally, this should not impact on the performance at all, but we guessed that this caused some nasty numerical rounding error or something similar when calculating the output integer value for driving the stage. Indeed, decreasing the maximum motor velocity from 3600 to 100 drastically improved the terminal angle precision by more than a factor of 10. So the terminal angle is now as accurate as ~mdeg with a repeatable bias of 70 counts or so.

Also, we noticed that the acceleration and deceleration times were set with respect to the maximum velocity, rather than to the requested velocity. As we decreased the motor maximum velocity, the acceleration and deceleration became more apparent. (Did we change some other parameters relating to the acceleration and deceleration ?)

In order to further improve the accuracy, Daniel and Vern installed an additional load resistor of 50 Ohm in the path that drives the motor. Because we made multiple changes at the same time, unfortunately it was unclear how much this improved the resulting angle accuracy. Nevertheless, according to the drive monitor, it is now able to stably and continuously drive the motor without stopping multiple times during a rotation action. So we think this additional load helped the overall performance somewhat.

We then tuned up the PID parameter again. After all, the P-factor (aka Kp) happened to be back to the default value of 200. The I-value (aka Ki) is currently 20, while the default value was 2. However, we found that Ki did not really change the behavior, this value seems fine for now.

Yesterday, before the HPO developed some problem, Rick and I made some ISS measurements. There was no surprise in that frontend signal was good with our without HPO, and HPO output was noisy.

The first image shows the analog DC output of HPO monitor before AOM (sorry for cell phone pictures). Accounting for the DC output level (-5.9V), RIN is about -56dB/sqrtHz at 10Hz, -116dB/sqrtHz at 10kHz. (This is about 16dB of so smaller than Peter's plot in alog 26832 which is labeled as "relative power noise". It seems to me that his plot agrees very well with my raw data, not RIN, so that's probably what that was.)

The second picture shows a temporary PD we set up on the table to measure the frontend output, stealing the light coming to the diagnostic bread board. (Though we were quite sure that the cable labeled as  "AMP DC" was indeed the DC output of "PD_AMP" diode on D0902114, since that diode is in the HPO box and there was no way to make sure except to open the HPO enclosure, we set this temporary thing up there.)

The third picture shows the output of the temporary PD when HPO was off. Accounting for 2.5V DC, RIN is about -74dB/sqrtHz at 10Hz, -135dB/sqrtHz at 10kHz. We did not check the numbers but the spectra didn't seem to change with or without HPO.

The fourth picture shows the 500kHz burst with 37kHz repetition rate in either HPO monitor DC or PDA (1st loop out of loop diode) DC. This went away when there was no light but we didn't check the AC out.

We certainly looked at 1st loop out of loop sensor spectrum with and without light, but I couldn't find the pictures. But we thought there was no surprise.

Kyle, Joe D.  

We removed the dying and obsolete iLIGO SRS RGA from VBOC and installed the latest/greatest aLIGO Pfeiffer Prisma Plus yesterday -> Today we took it for a test drive in both Faraday and Multiplier modes and it looks great.  This should have been done a long time ago.  The data finally looks normal!  We are baking this new RGA over the weekend -> VBOC should be available for Bake Loads by mid week.  
i
We are planning to rebuild VBOD's SRS RGA in the VPW and are considering baking it "nude" to expedite its clean-up.  We will also be replacing the RGA-tree isolation valve so VBOD will be out all of next week and perhaps longer.  

Kyle, Joe D. 

Chandra recognized the opportunity to bake the Vertex RGA while the IFO is down so we will file a WP on Monday to make the necessary pump connections and wrap it with heat tapes etc... -> The plan would be to bake it for 72 hrs. or so starting Monday afternoon.

EdM, RickS

During a PSL team telecon this morning, we decided not to try to operate the HPO until we can open the housing and inspect optical surfaces next week.

We decided to use this time to get the Diagnostics Breadboard up and running.

JimB updated the paths on the PSL ante-room workstation (pslws0)  so we could run it from there.

The HPO was disabled so it could not be started accidentally: currents set to zero (for nominal values, see photo below.  Note that they were increased by 1A during our investigations last night), DB power supplies switched off, DB power supply power cords disconnedted from back of units.

We closed the internal shutter in the HPO and switched on the Front End.

We adjusted the attenuator at the output of the HPO to minimize the power directed to the PMC (directed all of it to the power meter).

We then proceeded with the DBB measurements, following the detailed procedure in T1400730-v1.  We wanted to at least walk through the measurements to make sure everything with the DBB is functioning.

The RPD DC level is only 8.28 V.  Nominal is 9-11 V.  The power in this path is already optimized externally (we didn't open the DBB).  We proceeded with the measurement.

The RPN results are in: /ligo/lho/data/psl/psl_noisereports/2016-04-29/dbb_rpn-002.pdf and .zip  RPN is a bit above the nominal levels (factor of 2).  The fans in the laser room, and lights, are on.

The PMC locked locked without intervention in ~30 seconds.  We ran a CALI_ERRSIG calibration on the dither lock error signal.

The frequency noise (FRQ) scan results are in:  /ligo/lho/data/psl/psl_noisereports/2016-04-29/dbb_frq-001.pdf and .zip Huge peaks at 10 Hz and harmonics.  Something not right here.

We proceeded to the pointing (PNT) measurement.  We calibrated the QPDs. /ligo/lho/data/psl/psl_noisereports/2016-04-29/dbb_pnt-001.pdf and .zip Again, big peaks at 10 Hz and harmonics.

Proceeded with the modescan (MSC) measurement.  Results in /ligo/lho/data/psl/psl_noisereports/2016-04-29/dbb_msc-002.pdf and .zip The report shows 4.1% higher order mode power, which looks good if it can be trusted.

In summary, the DBB seems to be operational.  Some tweaking might be necessary to bring it to full usefulness, but it is working and the instructions for running it, along with the user interface, are very good.

Peter and I decided to leave the laser running in this state (FE only) rather than switch it off.  There is almost no light (< 1mW) directed toward the PMC.  The DBB shutters are closed, with the system in standby.

C. Cahillane

This aLOG should be the final uncertainty aLOG, at least for calibration between 5 Hz and 1000 Hz. I have generated many plots illustrating the uncertainty budgets, I will try to let them speak for themselves by explaining them one by one in order.
Whenever I have needed to choose a GPSTime for a plot, I have chosen 1135136350.

Plot 1: This is the classic analytic Response Function Error +- Uncertainty plot.  As usual, I have plotted R_C02/R_C03 to make the plot legible so you can see the systematic errors left uncorrected by C02.

Plot 2: This is a numerically-generated Monte Carlo uncertainty budget, as shown by the light-blue lines.  To generate the MC response functions, we sample from the posterior for each of the 14 parameters making up our response function, and then plot this "new" response as a series of light dots.  The light-blue lines represent the 68% confidence intervals of our numerical budget.  I have plotted the (dark) analytic budget on top here so we can compare the numerical and analytic uncertainty budgets.

Plot 3: I have quantified each parameter's individual contribution to our total uncertainty budget and error budget.  First we see the magnitude and phase uncertainty budgets themselves, then the uncertainty components plots, then the error components.  The error components are found by calculating the completely corrected "nominal" response function C03, then artificially removing a single component's systematic error and recalculating the response function for comparison with the nominal.

Plot 4: These spectrograms quantify our systematic error over all of O1.  The blue lines represent Sept 14, Oct 12, and Dec 26.

Plot 5: These spectrograms quantify our statistical uncertainty over all of O1.

Plot 6: These spectrograms quantify our "1 sigma maximum deviation" over all of O1.  What is 1 sigma maximum deviation?  It is the max of the absolute value of systematic error +- 1 sigma statistical uncertainty.  So if Error = -4% and Unc = +-3%, then the max deviation = max(abs(-4% +- 3%)) = 7%.  Apparently, many astro searches are incapable of correctly handling calibration error vs calibration uncertainty.  I must discourage ignoring this difference.  The green dots signify the time and frequency of maximum maximum deviation.

Plot 7: Percentile Plots.  I have taken the response error +- uncertainty spectrograms and compressed them into a convenient frequency plot illustrating the calibration spread over time.  The 68 percentile line, for instance, shows where the response error +- uncertainty lines were for 68% of the run time.  I have done this for percentiles 68%, 95%, and 99%.

For LLO, see LLO aLOG 25950

TITLE: 04/29 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: TJ
SHIFT SUMMARY: Due to PSL being down, not much in the way of OPS or Commissioning activity.  Some rotation stage work by commissioners.
LOG:

16:14 Kyle to HAM 5

16:21 Kyle out

16:43 Kyle to EX VEA

17:18 Kyle back from EX, going to EY

18:00 Kyle back

20:27 Richard to LVEA

20:32 Chandra overfilling CP3

21:02 Ed to PSL

21:45 Jim and Rich to CER looking at ITMy electronics

22:15 Joe to LVEA to retreive cable

22:26 Joe out

@ ~22:20 UTC. Noticed both HWS peak counts went bad. Stream images show no images. Powercycled the computer and restarted the code again. They're fine for now.

Installed a temporary Beckhoff box at Ham1.  This box contains a Rotation stage controller.  If other work does not pan out this can be used to reduce the length of signal cable to the motor.  The 25 foot cables run from this box into the PSL enclosure.  One would need to disconnect the existing cables and connect the new ones in their place.  The Beckhoff modules have been scanned waiting on software.

Since there seem to be some confusions about which PD has what kind of analog filtering and sent to which channel, here it is.

I'm quite certain about HPO output before AOM (which is "Power monitor PD" in D1002929) and ISS 1st loop monitors, but not that sure about "monitor PD"s in D1002164. E-travellers are incomplete (they don't say which one is installed where), so I'm just listing the nominal values for these "monitor PD"s.

Increased LLCV of CP3 from 18% to 20% because it took almost 9 min. to overfill today. 

MidY @ 1:40pm local

Opened CP3 bypass LLCV 1/2 turn with bypass exhaust valve open. Took 8:49 min. until vapor/liquid started to flow out the exhaust pipes. I waited several minutes before closing the bypass exhaust valve. Closed it a few times, pressure sounded high, so I opened it back up and then several seconds later liquid started to pour out. I did this three times, and then waited many minutes before finally leaving bypass exhaust valve closed.

Stefan, Evan

The attached plot shows the dark noise of the inner-loop ISS. It is "dark" in the sense that the NPRO is off, although there are still room lights on in the PSL.

PDA seems to have worse noise than PDB — a factor of 3 at 10 Hz. When the PDA/PDB inputs at the PSL rack are terminated, the noise performance is similar. So this excess seems to be somewhere between PDA and the PSL rack.

The traces are calibrated into equivalent RIN for the nominal ISS operating power.

Comparing with 26773 (for example), we see we are battling a noise that is more than a factor of 1000 worse than these dark noises.

HWSX peak counts bad, I stopped the code, powercycled the frame grabber and the camera, then restarted the code. Peak counts are back to normal (~940).

Made measurements of the oscillator power noise with a few photodiodes.

PowerNoise.png shows the free-running oscillator relative power noise
measured before the acousto-optic modulator.  This is more than 10 times
noisier than when the laser was installed in the H1 enclosure.  The
other trace in the plot is the out of loop of the relative power noise.
It is also about a factor of 10 higher than it should be.

    Whilst the power stabilisation was locked, I looked at the AC coupled
output of the photodiode and did not observe any oscillations.  The maximum
peak-to-peak variations were ~40 mVpp.