Miranda, Dave:

Friday afternoon we updated the cable labeling for the ACC BNC coax cables at EX, MX and MY. EY cables were already complete.

At EX we reconnected the BNC for H1:PEM-EX_ACC_OPLEV_ETMX_Y_DQ which we had found to be disconnected. Plot shows it had a signal until the 23rd June of this year.

(Travis, Gerardo)
The ion pump for HAM1 was incorporated to the HAM volume yesterday, and today the SS-500 pump cart was isolated from the chamber (turbo pump and SS-500 remain on), and as expected the pressure went up and now we are waiting for the ion pump to take over and maintain the vacuum pressure for HAM1.  We will be monitoring the progress of the ion pump.

(Travis, Gerardo)
We removed the old gauge a BCG-450 and installed a new one a BPG-552.  Since the gauge at this location does not play role with relays and such, the old pigtail did just fine, provided the power to the new gauge.  The new gauge is powered on and connected to the same EtherCAT cable as the one that that we removed.  Dead volume of this assembly is getting pumped down with a small can turbo pump and an aux-cart, and a very long flex hose, and probably will continue to pump over the weekend.
No issues were encountered while replacing the gauge.

(Travis, Gerardo)
This morning we checked HAM7 annulus system pumpdown and the aux-cart displayed 2.6X10^-05 Torr, good progress so it appears to be doing good.  We disconnected the SS-500 cart from HAM6 turbo and connected it to HAM7.  We checked all ports were "nominal", detached the active purge hose and no blowdown was done, since we had the relay tube valve (RV-2) open, took advantage of this and we let the purge air purge HAM7 overnight out RV-2.  After closing RV-2 we started the pumpdown of HAM7.  The purge valve (all metal valve) and the roughing valve at the turbo assembly were closed at 3.0X10^-05 Torr.
Attached is a plot of the pumpdown thus far.

Jennie W,

Since Daniel put in a TEC controller for the JAC temperature servo we will no longer use the current version of the guardian control loop so I have set JAC_HEATER guardian to SERVO_OFF. The TEC is turned on and the set point is at 25.4 Degrees C.

The servo controller can be reached by going to sitemap->IOO->JAC Overview->Controller. To turn it off select the 'OFF' button in the top right corner of the controller. The loop can be measured by using the excitation button noted in the picture.

I will trial this over the weekend so I can double check it doesn't drive the JAC away from the control point.

Here are some plots made with gwinc with Kevin's help of the effective loss for squeezing from different mode mismatches.  

The top left plot shows a reasonable guess of what the mismatch sizes were in O4: 2.5% sqz to OMC mismatch,  2.5% SRC to arm mismatch (G2600967), and 1% arm to OMC mismatch: G2600435 (indicated it could be as bad as 1%, or better).  How these three combine to make an effective loss for squeezing is frequency dependent and depends on the phase of the mismatch, which we do not know.  This results in up to 10% effective loss at a few kHz. 

The top right shows what happens if the sqz to OMC mode matching is improved to 0.3%, which we hope it will be after our recent psams changes (91551).  In this case the effective loss at high frequency varies from 5% to 1.6%.  

If the IFO to OMC mode mismatch is also improved to 0.3%, in which case the higher range of this loss is 2%.  When the two mismatches have similar size, it appears that they can cancel each other out to give very low loss.  In reality, these mode mismatches are likely limited by astigmatism and beam quality, and don't have a single mismatch phase like what is used in this model, and can't produce this neat cancelation effect, and the lowest loss options here won't be realistic.

The last plot shows that if we also reduced the arm to SRC mismatch to 0.3%, that has a small impact on the effective loss.  

TITLE: 08/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: Masayuki and Sheila worked on commissioning JAC and some ASC loops and corner alignment, there were two DAQ restarts and some model work, and HAM7 pumpdown started (2.25e-5 Torr as of 23:30).
LOG:                                                                                                                                                                                                                                                                                                                                                          

• ~15:08 UTC DAQ restart
• 16:00 UTC I started PR2 TFs then OLGs
• 17:00 UTC HAM7 pumpdown started
  • 20:30 Gerardo switched to the turbo pumps
• 17:40 UTC PR2 spot move
• ~19:40 UTC DAQ restart #2
• 22:13 UTC EQ mode from a 7.6 from Indonesia

Jennie W, Sina K, Erik V

Summary: Error found in heterodyne phase calculation and has been fixed but we are still confused about the heterodyne amplitude calculation.

Today I checked the local oscllator signals, beat signal and demodulated signals to debug our demodulation problems.

First check I did is with our nominal LO frequency of 4096 Hz. Top left plot is the sine and cosine signals from the digital local oscillator, bottom left is the beat signal from reference interferometer photodiode A.

Top right is the same signal after the demodulator in both I and Q. Bottom right is the demodulated signal after the filtering which has a comb at 4096 Hz and a low pass at 200 Hz.

Then I did another check of the same channels using 1024 Hz (which means I had to replace the comb frequency we use to filter out the LO frequency in the demdulator output).

Looking at the REF A IFO output signal, where the cosine and sine of the local oscillator are shown on the top left plot and the beat signal from the PD before demodulation is shown on the bottom left.

From the raw we can see that even with the phase block we removed this morning, the calculated heterodyne amplitude should be ~10Vpp and the mean should be around 5V. This would give a heterodyne efficiency of nearly 10/(2*5) = 100% for the reference interferometer.

The calculated amplitude in the model however is shown as ~3V in the top right plot however. The calculated phase (harder to check if this is correct by eye) is shown in the bottom right plot.

Per Sina's suggestion I checked the model and the demodulation calculation was:

Q = S(w) * cos(w_LO)

I = S(w) * sin(w_LO)

Then both I and Q signals are filtered to yield only the DC component.

The magnitude and phase of the interferometric measurement are calculated as:

|A_het| = Q_DC^2 + I_DC^2

angle(A_het) = tan^-1(Q_DC/I_DC)

This is incorrect and so we have now put in a change in the model so that the 'DEMOD' block in SPI_LIBRARY/HET_IFO_SPD/DEMOD calculates:

Q = S(w) * sin(w_LO)

I = S(w) * cos(w_LO)

All changes were saved and committed to the svn. The DEMOD block was a standard CDS library part so I needed to create a new version of this saved as 'hetdemod2.mdl' and use this in the SPI_LIBRARY instead. The part is saved in userapps/spi/common/models.

This is what this new block looks like. Erik also doubled checked that the arctan2 function used to get the phase is done as we expect.

After putting in the new model changes (alog #91548) the I and Q are swapped so this changes the phase but has no effect on the amplitude. So we still have another problem.

I did another measurement of REF IFO PD A. The demodulated I and Q channels are shown on the bottom right plot. Since I is roughly 0.7 and Q is roughly -2.5 we expect to calculate the values of 2.6V for the amplitude (bottom left plot) and -1.3 radians for the phase (top right plot) for the given I and Q values.

However looking at the raw signal (middle left plot) the peak to peak amplitude should be 10 and so there must be something else wrong with the way we are doing the demodulation.

[Sheila, Masayuki]

This morning we investigated the POP clipping. It is hard to say what is going on there. Our conclusion is that we need to use the picomotors to fix it, so we will wait until next week after the GV is open, and then work on finding good pico positions for POP and green.

- We started by maximizing LSC POP LF by moving the PR2 spot position. I used the PR2_SPOT_MOVE state of the ISC guardian and moved PR3 to maximize LSC POP LF and POP_X DC.  I also moved PM1 to look for a position that suits both.
- This way we can only maximize LSC POP, not LSC POP and POP X together. The maximum of LSC POP was ~7.5, with MICH on the dark fringe (REFL bright).
​​​​​​​- One strange thing we saw is that LSC POP behaved oddly during the PR3 sweep. As the attached time series shows, it has a broad flat shoulder. If this were simply clipping, the signal should rise continuously and then flatten at the top. We have not worked out what is happening there.

Jennie, Erik, Dave:

Jennie's latest h1spih23 model was installed at 13:49. No DAQ restart was needed.

Daniel, Erik, Jonathan, Dave:

At 12:39 we restarted the DAQ and the EDC to included a new H1EPICS_ECATISCCS.ini. This adds 43 new JAC-HEATER_CONTROL channels.

No issues with this restart.

[Jim W., Shoshana A., Michael R., Huyen P.]

0. Since HAM3 ISI has been updated with new CPS sensors (with fine vertical CPS), Jim updated new symetrization filters for the actuators using the ISI commissioning scripts.

1. We have been testing CRS in/out of loop looking at IMC length (mostly during night time with IMC locked at 2W). The wind condition has been relatively quite so far for these tests. We can repeat in higher wind (ground tilt) condition.

    We will try lower blend, e.g. 45mHz.

2. With CRS out of loop, we compared tilt spectra for CPS, GS13, and CRS. Without the proper capacitive damping, the OFFLINE/DAMPED stage rings up the CRS, making low frequency signal worse. Under ISOLATED state, the CRS can be damped, and CRS matches GS13 between 0.2Hz - 1 Hz. This test has been done at MIT, see alog 12136.

3. I also did make a different set of GS13 vertical symmetrization filters using global Z comb drive scripts from Brian, see last figure. The filter file is living under /ligo/svncommon/SeiSVN/seismic/Common/Documents/T2300404_HAM_symmetrization/ham3_fine_cps_and_crs/. We will test this later.

The new RCG separates the ADC and DAC overflow counters (previous RCGs combined them into a single counter). I have modifed the CDS Overview to show any model whose DAC counters are overflowing (counter > 0). This is shown as a purple square in the 6th block.  I have also added an overflow counter reset button in the lower right corner, called "OVRFLO RST", which issues an overflow reset on all models. Note that the overflow reset button resets both the ADC and the DAC counters.

Two models have continuous DAC overflows: h1tcscs and h1alsex. These are DC drives of 16bit-DAC channels

h1alsex

is driving its DAC ch8 (H1:ALS-X_WFS_AUTOC_PZT1_PIT_MON) with a dc signal of 35000, which exceeds the 16bit-DAC max value of 32768 before any upsampling.

h1tcscs

is driving its first 3 DAC chans each with a signal of 32768, which exceeds the operational range.

and is driving its DAC ch12 with a dc signal of 28521, which looks like it is in range, but after upsampling with zero-padding, produces an AC signal which spikes above 32k 2048 times per second.

We are investigating if we could change h1tcscs to no use zero-padding for its DAC. The main risks are with any non-DC drives, and possible recalibration for DC drives when they become actual DC signals.

Jennie W, Sina K, Jim W,

Yesterday we continued the checking we have been doing of the digital signal chain in CDS. We found that a lot of channels appear to be zero due to the decimation filters used on OUT16 channels and also that these were set to round the displayed channel to 1 significant figure. We corrected most of these on the main screen but I still have to go through the subsidiary screens and cross-check that we got all of these. Here are the new digital LO readout channels we introduced the other day (alog #91504) and here are the changes we made to monitored channel yesterday.

In the process we checked the calculation of the magnitude and phase of the reference and measurement interferometers (this is displayed in the 'monitor' block on the main SPI overview screen). The phase seems ok and indeed the 'phase unwrap' button that can be pressed to reset the phase of the IFO to zero after it accumulates more that 2pi of phase, seems to work well. We checked all the filtering done on the demodulated signals and those seem ok too.

Once we had checked all the signal routing we got signals out for the efficiency calculation. These seemed very low (~25%). After checking the raw PD into CDS against the calculated mean and peak to peak ampltiude of the beat signals which are used to calculate the efficiency, we realised that the efficiency should be above 80% but there is something wrong with the calculation of the peak to peak amplitude. To fix this we will try removing the phase rotator block in the interferometer simulink model as we think these blocks are unnecessary and might be doing something unexpected.

We also double checked the signal processing of the QPD channels and confirmed that these still need calibrated into radians of ISI motion. Per Jim's suggestion we will use the ISI sensors to calibrate these.

Summary: Most parts of SPI medm and model checked - still need to debug demodulation of signals for heterodyne interferometer.

Sheila, RyanC

I ran the full (all 6 dof) undamped TFs and the OLG templates for P and Y for PR2. For P and Y the magnitude of the TF was off. On the OLG for Y the magnitude is low, and we're not fully sure why. We doubled the gain of the P and Y damping loops from -0.5 to -1.0, this reduced the oscillation seen when moving sliders by ~half, see before and after... Also noting that PR2_Y sees the oscillation both in M3 and M1 whereas PR2_P only really sees it in M3. This is likely not the final solution but it helps for now.
I have accepted these two gain changes in the PR2 SDF safe file.

Masayuki, Sheila

When we step the alignment sliders in pitch or yaw on PR2, we see 1 Hz ringing for 15-20 seconds.  

R. Kumar, S. Dwyer, C. Compton, R. Short

Following the work done yesterday adjusting the preload on the ZM4 PSAMs (alog91471), Rahul and I set about adjusting it further today to get our calculated projected beam size on SRM close to where we want it. Using the same procedure as yesterday, I turned off the ZM4/5 PSAM drive chassis, Rahul went into HAM7, locked down ZM4, torqued the preload about 1/8" of a turn (it's hard to quantify a torque spec in this manner), then finally unlocked the suspension. I moved the ZM4 pitch alignment slider about -1400 counts to realign the beam on SQZT7 to our alignment irises as a result of this torque adjustment. I then proceeded to take a couple of beam profiles on the table with the M^2 device to see where we landed. This plot [initial] shows the difference between before and after this adjustment in terms of the projected beam at SRM with a few different PSAM settings on ZM4 and ZM5. The four points I took here informed us that we could stand to torque ZM4 a bit further to hopefully line up with the center of the plot.

Rahul went back into HAM7 and torqued another 1/8" and I took another couple of profiles after (I did not need to move ZM4's alignment sliders after this adjustment). I took a total of nine profile points here, all of which can be seen compared to other measurements today on this plot [full]. Since there are points in the bullseye, we decided to stop here and that this is where the ZM4 preloading will stay. This plot [final] shows just the beam profiles taken at our final preloading position.

Tomorrow we will move on to final closeout checks in HAM7.

Keita, Sheila, Tony,  Jennie W

Before the JAC PZT problem, I did get an hour or so of alignment time in.  Summary: we now have light on LSC POP and POP X for the same PM1 alignment, and ITMX is back to the alignment that should point down the arm.  We have the expected power in LSC POP path, but a factor of 20 too small in both DC and RF signals in the popair path. 

These screenshots show MICH fringes with 10W input power, where I started and where I ended.  The idea was to move to the ITMX alignment that Jenne Driggers found using the arm beam here: 89738.  I watched the mich fringes and AS camera while moving the ITM, moved the beam splitter to keep the michelson fringes, and as Keita suggested moved PR3 to keep the beams on the ISCT1 refl camera.  This did cause the michelson fringes on the LSC pop diode to get smaller, when that happened I paused, went to the PR2 spot move guardian state, and adjusted PR3 to bring the fringes back on LSC POP.  After bringing the ITMX yaw alignment back I could see that there is now light on POPX and LSC POP A for the same PM1 alignment.  

When I walked ITMX pitch, I had to also adjust yaw several times as I went along to keep the mich fringes.  I also adjusted PRM to keep PRX alignment good as I moved along. Looking at this screenshot of the brief time when PRMI was flashing, the POP A LF flash was about the O4 power level (91211), as was reflair A, but popair has too little power.   The result of this was that PR3 started the day 56urad away from the O4 slider, but is not -15urad.  PR3 yaw started the day close to the O4 slider but is now -47urad.

I also adjusted the POP X dark offsets so that this QPD will be less confusing to read, SDF screenshot attached.

We tried walking PR3 in PR2 spot move to allow us to centering POP X without saturating PM1, this alignment is shown in this screenshot, but when we then aligned PM1 to put the beam on LSC POP, we were missing power there.