J. Kissel
ECR E1500045
FRS 6014
WP 6051

While attempting to quickly install the ITM updates in between the HAM6 work, I found that ITM models would not compile as is. Errors in the compilation process reminded me that their upgrade would not be as simple as copying and pasting from the ETMs (thanks for all the great error messages, Rolf! They're, sincerely, very useful nowadays). This complexity a result of the differing BIO control of the ESD stage drivers, so the BIO block as a whole cannot be the same. 

Further, I discovered that I forgot to switch the EUL2OSEM matrix on the FOUROSEM_DAMPED_STAGE_MASTER_WITH_DAMP_MODE.mdl library part that controls the L2 stage of both the QUAD_MASTER.mdl (for ETMs) and QUAD_ITM_MASTER.mdl (for ITMs) from a regular matrix to a ramping matrix.

This means that the ITMs are ready for install, and the ETMs need a re-install to gather this bug fix. I'll coordinate with the HAM6 install/repair team and with the CDS crew. 

I've since made the model changes, and all QUADs now successfully compile, but all QUADs will need to have these models installed and rebooted. 

For future reference, changes have been made to 
/opt/rtcds/userapps/release/sus/common/models/
QUAD_MASTER.mdl                  << Modified the BIO block to use the new Individually Controlled 
                                    PUM library block, arranged connections from BIO to L2 
                                    blocks accordingly
QUAD_ITM_MASTER.mdl              << (same as above) Modified the BIO block to use the new 
                                    Individually Controlled PUM library block, arranged 
                                    connections from BIO to L2 blocks accordingly
STATE_BIO_MASTER.mdl             << Created new library block for individual control of PUM driver
FOUROSEM_DAMPED_STAGE_MASTER_WITH_DAMP_MODE.mdl     << Modified COILOUTF bank to accept individual control
                                                       and switched EUL2OSEM matrix from static to ramping

and they've been committed to the userapps svn repo. I attach screenshots of all the relevant parts that have been modified, named after the simulink blocks, respectively.

Removed temporary extension cord for GV15 AIP329 and replaced it with new extension cord, work done under WP 6060, and this closes FRS ticket 5950.

State of H1:  OMC work continues, progress on PDs

Activities:

• 19:08 - Krishna - back from LVEA
• 19:08 - Michael - back from LVEA
• 19:50 - Krishna - back from LVEA
• 19:50 - Michael - back from LVEA
• 19:57 - Kyle - EY - temperature readings
• 20:11 - Koji, Corey, TJ - back to LVEA OMC
• 20:30 - Robert - EY
• 20:38 - Richard - LVEA OMC
• 20:39 - Kyle - back from EY
• 20:55 - Jason - Optics Lab
• 20:58 - JeffK - ITMX and ITMY model restarts

~1330 hrs. local 

Opened exhaust check-valve bypass-valve, opened LLCV bypass-valve 1/2 turn -> LN2 @ exhaust in 45 seconds -> Restored valves to as found configuration. 

Next CP3 overfill to be Monday, August 8th.

Chris B. and Ryan F. reported that during the hardware injections in ER9, the H1:CAL-PINJ_TRANSIENT_OUT channel did not fall below 1e-200 counts until about 1 hour after the last BBH injection. He also said this was not observed in O1. One needs to consider the following two points:

First, one cannot directly compare the TRANSIENT_OUT channel from O1 and ER9 because they had fundamentally different units. In O1, the channel had units of strain, in ER9, it had units of counts. In ER9, the strain time series has passed through the inverse actuation filters.

Second, if one instead looks at the HARDWARE_OUT channel in O1 (after the IAF during O1), any impulse response to the transient signal ending would be completely masked by the continuous wave signal that has been added to the HARDWARE_IN time series. Thus it doesn't make sense to have a 1e-200 threshold on the HARDWARE_OUT channel during O1.

To invstigate the ER9 IAF, I have separately computed the impulse response of the different filters. The biggest impulse response comes from the f^2 filter module because it has high gain at high frequencies (see first attachment). This is to be expected.

I also compare the impulse response of the IAF used in O1 and the IAF used during ER9 (second and third figures, respectively). The O1 actually has a bigger impulse response and longer duration. I would surmise from this that any oscillations are actually worse in O1 than they are now.

Conclusion:
From this investigation, there is nothing to suggest that the ER9 IAF are worse than O1. In fact, the new IAF provide improved signal fidelity and the impulse response suggests that the new IAF is actually better than the O1 version.

J. Kissel, K. Arai, C. Gray, T. Shaffer, B. Weaver

After a great deal of inspection of the top mass, where I thought the OMCS was locked last night (see LHO aLOG 28883), the in-vacuum team list above identified that an earthquake stop on the bottom mass / breadboard / M2 stage was rubbing slightly. Once this EQ stop was backed off, all DOFs of the suspensions top to top mass dynamics returned to the expected results akin to the former OMC. Nice work team!

Attached are screenshots of drawings of the OMC with the offending EQ stop highlighted with a red square, as well as the transfer functions themselves. On the transfer function plots, 
BLACK shows the former OMC reference measurements, 
BLUE is yesterday's measurement with the EQ stop rubbing, and 
RED is the current OMC suspended, free of rubbing.

Templates for today's measurements live here:
/ligo/svbcommon/SusSVN/sus/trunk/OMCS/H1/OMC/SAGM1/Data
2016-08-05_1909_H1SUSOMC_WhiteNoise_L_0p2to50Hz.xml
2016-08-05_1909_H1SUSOMC_WhiteNoise_P_0p2to50Hz.xml
2016-08-05_1909_H1SUSOMC_WhiteNoise_R_0p2to50Hz.xml
2016-08-05_1909_H1SUSOMC_WhiteNoise_T_0p2to50Hz.xml
2016-08-05_1909_H1SUSOMC_WhiteNoise_V_0p2to50Hz.xml
2016-08-05_1909_H1SUSOMC_WhiteNoise_Y_0p2to50Hz.xml

Notes: 
- Because I wanted yesterday's measurements in the template as a reference, and we were in rush, I did not head my own advice and use the templates from 28736. Just keep this in mind. At least, this time, I'd paid attention to the frequency resolution and made it the same 0.02 Hz BW across all DOF's templates, but I did not add in the low-frequency boost. Again, one can stil get the information needed out of these templates, but they could be better.
- I only took a few averages. This is the luxury of having reference transfer functions and suspensions with very repeatable dynamics: we know immediately -- even after one average -- that if the resonance frequencies, zero frequencies, and their respective Qs line up with the reference then the suspension is healthy. More averages will just reduce the incoherent noise on the TF at all frequencies, and since these measurements are in air, we expect a good deal of incoherent noise at all frequencies anyway.

State of H1: OMC PD electroincs pulled for testing - issues are ongoing, OMC suspension issues are resolved

Activities: all times UTC

• 15:24 - Koji - LVEA - OMC - electronics check at HAM6, back
• 16:12 - Kyle - EY - check on bake
• 16:25 - Betsy - LVEA - getting batteries
• 16:31 - Koji - optics lab then LVEA OMC - OMC alignment
• 16:51 - Christina - EX - cleaning
• 16:55 - Betsy - LVEA OMC
• 16:59 - Richard - LVEA OMC - checking out electronics
• 17:07 - Richard - out of LVEA - has pulled the chassis for PDs and has it in EE
• 17:10 - Robert - EY - may cause a trip - cleared with JimW
• 17:21 - Bubba - EX - wind fence
• 17:29 - Richard, Fil - LVEA OMC - chassis back out to the floor
• 17:37 - Corey - LVEA OMC
• 17:42 - Micheal,Krishna - LVEA vertex - seismometer
• 17:52 - Richard - back from LVEA, Fil still in LVEA
• 17:55 - Bubba - back from EX
• 17:58 - Jason - Optics Lab - inspecting TCS mirrors
• 18:00 - Gerardo - MX - WP6060
• 18:00 - TJ - LVEA OMC
• 18:05 - Christina - leaving EX
• 18:10 - Chandra - EY then EX - viewport cover inspection
• 18:54 - Gerardo - back  from MX
• 18:54 - Stefan - LVEA OMC
• 18:58 - Fil, Corey, TJ, Koji, Stefan - out of the LVEA

Dust:

• 17:40 - EX dust - yellow alarm
• 18:02 - EX dust - red alarm

Alignment:

• 18:51 - HAM5 ISI Trip, now recovered

J. Warner

Jim has put gathered some data on the wind fence. Check out SEI aLOG 1050.

Chandra, Gerardo, Patrick

Degassed the two nude ion gauges in corner station - PT170 & PT180 on BSC 7 & BCS 8. First degassed PT170 (700degC for 3 min. according to manual). We monitored the adjacent PT120 CC gauge, where pressure barely rose (8.48e-9 Torr to 8.52e-9 Torr). Pressures at the two ion gauges rose significantly and caused a verbal alarm at the operator console; pressures spiked to ~2e-7 Torr and then settled down to base pressures.

Note:  degassing draws ~ 70 W and thus caused PT120 pirani to flat line and CC to read bogus pressure reading during degassing. This happened during PT180 degas, but not with PT170. 

We also noticed that PT140A periodically flat lines - linked to PT110 (?).

System Check-In and issues discussed:

OMC:

• SUS OMC - JeffK - OMs look ok, more testing today of OMC suspension
• SUS OMC - Koji - new OMC PDs - scanned and saw issues - alog 28891
• VAC OMC - ongoing investigation into how vaporized glass effected the pressure in HAM6, i.e. pressure spikes

All other systems / issues:

• SEI - JimW - testing AC coupled loops on ITMY - done now, no alignment changes
• SEI - Sudarshan - BRS - noise
• SUS - JeffK - QUADs - ETMs upgrade already loaded, ITMs still to be upgraded
• CDS - Richard - testing WFS at EY, EX
• CDS - Richard - working on new fault reports
• PSL - Jason - no reported issues
• VAC - Chandra - heating a couple PT100s in the LVEA - BSC7 and BSC8
• VAC - Kyle - bake at EY continues
• VAC - Chandra - y28 ion pump is fixed
• VAC - Chandra, Betsy - changing gauge on top of HAM6 early next week
• Facilities -  Bubba, Chris, Joe - wind fence at EX

Visitors next week: Aug. 8-12

• Koji - visit continued from this week
• Krishna - visit continued from this week
• Ian Gomez - grad student from Stanford
• Calum, Norna, Stephan from CalTech

The OMC scan was performed last night after the chamber was covered. While the scan showed noimnal resonant features of the slightly misaligned cavity, I saw negative trips of the DCPD outputs (both) when the photocurrent is of the order of ~0.1mA. 

The attched plot shows the refl QPD sum (CH1), scanned PZT Voltage (CH2), and the DCPD A/B outputs (CH3/4). The output of the DCPDs are usually positve, while they trip to negative occasionally when the cavity hit the major resonances. The positive voltage segments show nice resonant features when they are plotted in a logscale.

The refl QPD sum shows that the light was nicely absorbed by (transmitted through) the OMC. So it seems it is not optical.

I quickly checked the power supply condition of the field rack and confirmed that the related chassis are on.

We want to figure out this feature by the time we close the dorrs next week as the DCPD preamps are located in HAM6.

State of H1: progress with OMC, other work continues

Activities:  all times UTC

• as of 15:13
• 13:24 - Bubba, Chris - LVEA - scissor lift and batteries
• 14:46 - Chris, Joe - EX - wind fence
• 15:00 - JimW - ITMY - 20 minute measurement

LHO ALOG 28765 said: "We reached 30 (as measured by LSC-PR_GAIN - Evan claims this is more like 35)."

I have the same impression based on the IFO visibility (reflectivity) estimation from the power recycling gain. My rough estimation says LSC-PR_GAIN is ~15% underestimated, which is quite consistent with Evan's claim. His estimation of the PRG is based on the difference of the transmitted light level between the single arm lock and the full IFO.

The first attached plot shows the comparison of the measured and estimated IFO reflectivity (or visibility). The data was taken from four lock stretches on Jul 26. The measured value (magenta) was normalized to have the unity when the IFO was not locked. Also it was normalized by the incident power. This visibility includes the power of the modulation sidebands and the rejected junk light. So even if the IFO is critically coupled, it does not go down to zero. In stead, it goes to 0.018, which is an empirical number came from the second analysis.

Basically, I couldn't reproduce the measured visibility with the power recycling taken from LSC-PR_GAIN. The red curve was estimated from LSC-PR_GAIN using a Fabry-Perot model formed by the PRM (T=0.031) and the perfect mirror with a loss between them. The blue curve is the estimated loss (or say, the reflectivity defect of the compound mirror by FPMI+SR). When the incident power (not shown here) was increased in every lock stretch, the power recycling gain went down and thus the estimated loss went up. But more reflection was expected because of severe undercoupling. In reality, we didn't have such amout of reflection. Also during the power up, it seemed that the IFO was still undercoupled, while the estimation showed less reflection.

If the power recycling gain is scaled by +15% (times 1.15), we can explain the measured visibility better. The second attachment is the same analysis with the PRG scaled. We have better explanation of the initial overcoupling part, the dip at the critical coupling, and the low reflectivity at high power.

The same effect can be obtained by changing the PRM transmissivity from 0.031 to 0.036. However, it is an unlikely assumption.

We probably can imprve the model by taking the sideband recycling gains and the modulation depths into account. If the model is made precise enough, we might become able to estimate the ammount of the junk light due to thermal lensing, for example. Also this analysis gives us realtime monitor of the internal loss in the IFO and this gives us more sensitive measure how good the IFO alignment/lensing is, compared to looking at the power recycling gain which is a small change of a high number like 30.

[Betsy, Corey, TJ, Koji]

- Now the OMC cavity is flashing!

- The OM1~3 and OMC suspensions have been debiased, and the OSEMs were tweaked to have the flags at the center of them.

- The optical paths such as the OMC incident path, OM1 transmission path, OMC refl path ahve been aligned.
  We still need to align the WFS and OMCT paths and confirm viewport paths if the beams are hitting the viewport.

- Currently the OMC PZT HV is ON.

=== Details ===

Shutter mirror inspection

The surface of the shutter mirror was checked with the green lantern. We didn't observe any sign of degradation.

Mass balance

- We adjusted the weight of the new OMC to match with the old one as much as possible. Then the mass was moved to have reasonable flag positions in the OMC suspension.

- The lateral position of OMCS RT OSEM was adjusted to have the flag at the center in the OSEM.
- The centering of the OMCS OSEMs were checked to be within the tolerance range.
- Along with the mass balancing, the positions of the EQ stops for the OMC breadboard were checked. We found several EQ stops were too close or too far. The EQ stop holders were adjusted to have them reasonable gaps to the glass breadboard.

Electrical functionality check

- The DCPDs were illuminated by a white flash light to check which DCPD responds to which channel. DCPDA and DCPDB are related to the DCPD on the transmission anfd reflection sides of the BS prism, respectively. (DCPD(T) = DCPDA, DCPD(R) = DCPDB). This seemed opposite to the case with the previous OMC. It was found that the difference in the internal cabling on the OMC caused this difference. This will be noted in the OMC testing procedure document (T1500060) athough this does not affect the calibration.

- The OMC QPDs were illuminated by the flash light. QPD1 (short arm) and QPD2 (long arm) correspond to QPDA and QPDB, as nominal.

Incident beam alignment & suspension debiasing

- Prep: IMC was locked at 2W. The beam was aligned on to the center of AS_C QPD.
- At this point, we already could observe the beams were on the OMC QPDs. Very good reproducibility.
  The signal ratios between OMC_QPD_A/B_SUM and AS_C_QPD_SUM (0.56 and 0.59 today) were confirmed with the ones with the numbers on Jul 28 (0.48 and 0.45).
  These ratios were enough similar to convince ourselves that they are the real spots.

From this point, we could follow the procedure in T1400588 (sec 2.3.3 and later).

- OMCS and OM3 were debiased to have (0,0), and used OM1 and 2 to align the spots on the OMC QPDs.

- This made OM1 Yaw ~-2000, and the OMC2 Pitch ~1500.

- The OM1 suspension cage was twisted to remove the OM1 Yaw bias.
- The OM2 suspension pitch adjustment screw was adjusted to remove the OM2 Pitch bias.

- The resulting offsets were: OM1 (116.9, -229.0), OM2 (94.5, 113.0), OM3 (0,0), OMCS (0,0) => Requirement <250 = 1/10th of the full scale => OK!

- We quickly checked some suspension transfer functions for OM1/OM2 and OMCS. OM1 and OM2 showed consistent TFs as the previous measurements. OMCS had the same resonant structures as before except for the resonant frequency of the lowest frequency mode. JeffK is checking the TFs more carefully.

- We turned on the PZT HV and scanned the PZT2 voltage. We confirmed that the OMC DCPDA and DCPDB were observing the OMC flahses.

Optical path check

- Main path: The spot positions on OM1/2/3 were checked. They looked fine.

- Shutter path: The mechanical shutter path was checked. It is still nicely aligned.

- OM1 trans path: The beam alignment in the OM1 transmission was checked. They looked fine. We still need to check the AS AIR viewport path with the viewport emulator.

- OMCR path: The beam spots on the OMCR steering mirrors were checked. The beam was not on the center of the steering mirrors. The first steering mirror (so-called M8) in the OMCR path was moved. The reflection path for 90:10 BS and the beam diverter path was checked. They looked just fine. M10 and M11 were used to align the spots on the OMCR QPDs. We didn't use M9 this time. We'll check this path again once the viewport emulator is attached on the chamber tomorrow.

- WFS path / OMCT path: We will work on these paths tomorrow.

Next steps

- Restore OMC blackglass shroud if the OMCS TFs look OK.

- Restore OMCT steering mirror

- Place the viewport emulator

- Confirm spot locations on the viewport

- We want to check the calibration between AS_C QPD SUM, the incident power on OM1, and the incident power on the OMC breadboard.

- Ground loop check

- Other SUS/SEI exit check

The HV power cable for the Y2-8 ion pump has been repaired. The damaged section was cut off, and the cable was spliced together. Cable was tested with the HI-POT tester to 5KV.

The shot noise level from last night seems higher (worse) than the O1 level by 6%. Here is the spectrum:

You can see that the red trace (which is the one from the last night) is slightly higher than the (post-) O1 spectrum. The 6% increment was estimated by dividing the two spectra for frequencies above 1200 Hz and taking a median of it.

J. Kissel, E. Goetz

We've taken another DARMOLG TF and PCAL2 DARM transfer function in order to see if / how the SRC Detuning Optical (Anti-)Spring is changing from lock-stretch to lock-stretch. The bad (but not necessarily unexpected) news: it looks like the optical (anti-)spring frequency is moving around. One can tell by looking at the lowest frequency data points in the .pdf attachments. The model has a spring frequency of 9.381 Hz and both measurements are divided by it to form the residuals on the right column of subplots. Note also that Kiwamu and Craig's more sophisticated parametrization for the optical spring (which includes some Q between in the anti-spring poles, see LHO aLOG 28274) is not yet included. Jul 1 data points are ~ +15% discrepant in magnitude, where as Jul 09 data points are ~ +25%. 

More thoughts on this (what to do about it, how to track it, tests to try and control / reduce it) after the weekend. 

The pre-processed sensing function has been attached here, such that whomever gets to it first, can reproduce the fit using Craig's code from LHO aLOG 28274.

Data sets live here:
${CalSVN}/trunk/Runs/PreER9/H1/Measurements/DARMOLGTFs/2016-07-09_H1_DARM_OLGTF_4to1200Hz_SRCTuned.xml
${CalSVN}/trunk/Runs/PreER9/H1/Measurements/PCAL/2016-07-09_H1_PCAL2DARMTF_4to1200Hz_SRCTuned.xml