We found that the pitch and yaw outputs for the y-arm initial alignment were flipped. Fixed the model and recompiled.

h1asc.mdl: SVN revision 7011.

Following updates of guardian at LLO from the past few weeks, I started updating some sus guardian

New feature for saving alignment :

It is now possible to save the aligned as well as the misaligned position of the suspensions for every optic. This can be done through the IFO_ALIGN medm screen via the Save Alignment menu (cf IFO_ALIGN.png) or with the pyhton script align_save_burt -a -m living in /opt/rtcds/userapps/release/sus/common/scripts/

For more details see llo alog 10436 and 10466

Restoring the saved alignments :

This is done through Guardian by switching between different states of the suspension. Guardian medm screens can be accessed via the ! G buttons in the IFO_ALIGN medm screen (cf IFO_ALIGN.png).

For now, only PRM PR3 and MC2 are running under the guardian and can be restored this way. For the other suspensions, it will need to be done manually (until a guardian process is created).

When the guardian medm screen is open, it is straightforward to switch between aligned misaligned damped or safe via the "REQUEST" menu (cf GUARD_PRM.png)

IFO_ALIGN.adl was updated from livingston but I had to make some modifications to get the links functioning. The new adl file was commited under the svn

1) As Kiwamu pointed out to me, the arguments under the Save Alignment link were in the wrong order (e.g. "align_save_burt MC1 -m" instead of "align_save_burt  -m MC1"), so I modified it for MC1/MC2/MC3/PRM/PR2/PR3/SRM/SR2/SR3/BS/ETMX/ETMY/ITMX/ITMY/TMSX/TMSY

2) Also, the command to create a guardian medm screen (guardmedm) had the full llo path defined (/ligo/apps/ubuntu12/guardian/bin/guardmedm) which doesn't exist here so I changed it to guardmedm without the path. That should also work at llo.

J. Kissel

Though we're confident that the only way to improve the X-arm Test Mass angular performance is to improve the BSC-ISI performance between 0.3 and 0.7 [Hz], I tried tweaking the Level 2.1 Damping Loop design to see if I could do any better, by increasing the Q of the boost filters on the L and P degrees of freedom. Further, I moved the frequency of the P boost down from 0.56 [Hz] to 0.51 [Hz] to account for the difference between the modelled and measured frequency of this mode. Regrettably, I could not improve the strength (at the resonances) of the boosts much more than 5 to 10 [dB] without destroying the the stability of the L & P loops -- I'd already pushed the phase and gain margins of the *lower* unity gain frequency pretty far. As such, the improvement was only in the sharp frequency regions over which I'd focused the boost, but little-to-no change in the RMS. 

We'll continue to work on improving the performance of the ISIs. 

For posterity, I post all of the design information and performance comparisons. The good news is, that my MIMO model of the QUADs can now accurately predict the optic angular motion -- especially Pitch -- at all frequencies where not limited by its sensor noise. Check out the pg 2 of the third attachment for proof!

Details:
---------
allquads_2014-01-31_AllGoodFibers_P.pdf 
     -- Shows a collection of transfer functions of all monolithic suspensions. It shows that compared against the modeled first, top mass, P2P mode at 0.56 [Hz], all the measurements show that this mode is at 0.51 pm 0.01 [Hz]. This is what motivated me to focus the sharp P boost at a lower frequency.
2014-01-31_H1SUSETMX_M0_DAMP_Filters.pdf
     -- Bode plots comparing the 2013-06-14, Level 2.1 Filters against the new 2014-01-31 Sharp Boost filters. 
dampingfilters_QUAD_2013-06-14_Level2p1_2014-01-30_H1ISIETMX_Seismic_SelectPlots.pdf
     -- Using current seismic data input, this is a few select plots from the loop design script for the 2013-06-14 Level 2.1 filters. As mentioned above, it predicts the measured P motion extremely well below ~1.5 [Hz]. Interestingly, the Y prediction is not perfect, but I suspect that below 0.5 [Hz] the signal is dominated by L and P motion of test mass, confused as Y. Especially because the two extra modes that appear at ... you guessed it 0.44 and 0.56 [Hz].
dampingfilters_QUAD_2014-01-30_Level2p1_RealSeismic_SelectPlots.pdf
     -- Selected performance plots with the new sharper boost. Bare in mind that I've used the *model* for the predicted transfer functions, which don't get the first P mode at the right frequency. That's why things appear like they will be unstable, and all sort of gain peaky near the lower unity gain frequency. 
dampingfilters_comparison_2013-06-14vs2014-01-31.pdf
     -- A comparison between the two designs. 
2014-01-31_H1SUSETMX_Level2p1vsSharpBoost_Performance_ASDs.pdf
     -- A comparison of the optical lever performance between the two configurations. Of course, the spectra were taken at different times of day, so above ~0.6 [Hz] the input motion is a little different, but below 0.6 [Hz] the motion is the *same*,  and one can see the expected change in shape of the hump, but no change in RMS. Oh well.


Design Scripts:
SusSVN/sus/trunk/QUAD/Common/FilterDesign/Scripts/
compare_quad_dampfilter_design_20140131_NormalvsSharp.m
design_damping_QUAD_20130614.m
design_damping_QUAD_20140123.m
plotquaddampingcontroldesign.m

Filters and Model saved to:
SusSVN/sus/trunk/QUAD/Common/FilterDesign/MatFiles/
dampingfilters_QUAD_2013-06-14.mat
dampingfilters_QUAD_2014-01-30.mat
dampingfilters_QUAD_2013-06-14_Level2p1_2014-01-30_H1ISIETMX_Seismic_model.mat
dampingfilters_QUAD_2013-06-14_Level2p1_RealSeismic_model.mat
dampingfilters_QUAD_2014-01-30_Level2p1_RealSeismic_model.mat

Due to the non-zero chance of a second cooling unit failing, we are leaving the doors between the MSR and the hallway open for the weekend. We should keep the control room doors closed to reduce the noise.

I made a calibration of the IM4trans and MC2trans SUM channels into uW.

The conversion from W incident on the PDs to counts registered on IMC-IM4_TRANS_SUM_OUTMON is as follows:

[counts/W] = responsivity [0.16 A/W] x transimpedance gain [1000V/A] x differential to single input gain [2V/V] x whitening gain [36dB=63.1 V/V] x ADC gain [1.6384x10^3 cts/V].

This is actually the same for both MC2trans QPD and IM4trans QPDs: 2.087x10^9 [counts/W]

I used this calibration factor to calculate the power on IM4trans and MC2trans currently:

IM4trans counts ~= 57890 counts, which converts to 1.75mW. Comparing this with the expected power on IM4trans:

8.73W into IMC * 0.85 IO throughput * 2400ppm IM4 transmission * 0.1 transmission of BS between IM4 and IM4trans QPD = 1.78mW

MC2trans counts ~= 2.17x10^4 counts, which converts to 655uW. Comparing this with the expected power on MC2trans:

8.73W into IMC * (IMC gain = IMC Finesse/pi = 166 ) * 5.1x10^-6 MC2 transmission * 0.1 transmission of BS between MC2 and MC2trans QPD = 740uW.

Both these estimates for the power incident on each PD agree pretty well so I'll go ahead and add a new filter called "cts2uW" in the SUM_OUTMON paths to give the outputs in uW incident on the PDs.

Aaron, Luis, Fil, Sheila

There is now a camera installed on the IR trans path at the x end.  The image is of the IR path incident on a baffle (a scratched up, old piece of aluminum painted black, to be more acurate.)  There is about 30uW of green power coming out of the chamber into the IR path, you can see a square of 4 green ghost beams on the camera image, and ocassional flashes of the IR beam.  Adding a dichroic to the path might make it a little more clear what is going on here.  

We sent the signal to the red cable behind the monitors in the front row of the control room.  I unplugged the image of the BS from the top monitor, and replaced it with this camera.  IF anyone want to see the BS camera, plug the blue cable back in.

8:53-9:43 Checking SUS cables on HAM 4 (LVEA) - Filiberto
9:07-10:10 Moving, cleaning, and organizing elements for SR2 installation (HAM4 LVEA) Jeff.B/Jodi
9:40-10:40 Going into LVEA to check a dust monitor which has lost     communication Patrick
9:47-11:20 Heading to LVEA West Bay (cleaning/organizing ACB components) – Mitchell
10:15-12:15 Stiffener rings and o ring protectors installation on HAM4 – Apollo
10:33-11:53 Going to HAM 4 to install SR2 Pre-installation Plate(Cookie cutter) – Jeff B.
12:40-12:46 DAQ restart and new h1asc model – Dave
12:54-13:17 Going to BSC2 to work on HEPI – Hugh
13:30-15:11 Heading to LVEA West Bay (cleaning/organizing ACB components) – Mitchell
13:44-15:12 Going to HAM 4 to install SR2 Pre-installation Plate(Cookie cutter) – Jeff B.
14:22-15:05 Heading into the LVEA to search for cables - Corey

J. Kissel, R. Mittleman, R. McCarthy

Looking for functional STS-2s to use for BSC-ISI sensor correction at ETMX, one suggestion that came up was the Vault STS-2. However, Rich immediately reminded us that it's over 10 years old and hasn't received any TLC in a while, so it's most likely functioning poorly at low-frequency and will need to be shipped back to Quanterra for maintenance. To confirm, I've measured its low-frequency coherence with the functional corner station STS-2s. Ideally, we'd go grab the VAULT STS2, and huddle test it against one of the LVEA STSs, but ... it's cold, and for the frequencies we're concerned about it shouldn't matter.

In summary -- yes: the VAULT STS-2 is poorly coherent with any of the corner. If functional, we'd expect to see coherence down to 50-60 mHz in the Z directions. Richard suggest we'll grab in the Spring.

Details:
--------
Serial Number Layout:
HAM2 -- SN 89922
HAM5 -- SN 100145F
ITMY -- SN 89941
VAULT -- (Known, but not yet by me)
(ETMY -- SN 89938)

Calibration Details:
HAM2, HAM5, and ITMY -- 1e-9 [(m/s) / (nm/s)]. These aLIGO GND STS2s, with channels H1:ISI-GND_STS_${CHAMBER}_${DOF}_DQ, are already calibrated in the front end to (nm/s), so all I have to do was convert to (m/s).
VAULT -- 3.052e-7 [(m/s) / ct]. Although pem.ligo.org suggests that the calibration should be 0.0076e-6 [(m/s) / ct], it did not match any of the corner station STS-2s at the microseism, where the motion should be identical. So, I just scaled the VAULT to match. Further, the channels are different from pem.ligo.org, they're now H1:PEM-VAULT_SEIS_1030X195Y_STS2_${DOF}_DQ

At COB yesterday we had roughed in the longitudinal, lateral, pitch and yaw positions of the ETMy test mass within the suspension structure.  We had to push the structure ~3mm to achieve this.  Today, while bringing the height into alignment, we threw the yaw out of tolerance (because the height mechanics are grossely coupled to yaw).  After finally getting the height into tolerance (iterate: go up, whoops too far, go down, no up, now down!) we re-tuned yaw to within ~300uRad.  We still need to work on yaw more but our backs were literally breaking getting to these adjustments (see pic) so we opted to stop there and start fresh on Monday.  We now have the long, lat, and height within spec with the pitch and yaw almost in spec for the main chain.  We also adjusted some bad roll on the reaction ERM which for some reason induced pitch.  We'll attack that chain Monday.  IAS plans to bring the gap measuring aparatus out on Monday which we'll need to use soon.

It is now using the file /ligo/lho/data/conlog/h1/pvlist_1391196748 (attached). There are 99,264 channels in this list. 5,755 are currently unmonitored.

Work completed

We fixed Daniel's channel naming problem with the ALS addition to the ASC, actually the problem went away. So I restarted the new h1asc model at 12:41 and restarted the DAQ at 12:44 to install the new model and DAQ channels associated with it.

Noticed some fluid in the bottom of the SW SEI Pier at the BS.  Cleaned up the mess in the Pier yesterday and this morning found fresh fluid.  Climbed up to Housing and found the Vertical Actuator Fluid Catch overflowing.  I can see drips coming off the Parker Valve.  Can't tell if it is coming out of the Valve itself or just the Valve/Manifold seal.  It looks like it could be the former.  I'd like to clean up the catch and tighten the valve to manifold screws and see what it looks like in a couple days.

This may require a valve change which would briefly glitch the fluid pressures twice and in between have the BS HEPI uncontrolled for a few hours as we bleed after the valve change.

Starting Stiffener rings and o ring protectors installation on HAM4 - Apollo

I have been silently checking the signal chain of the REFLAIR and POPAIR RFPDs using the AM laser (a.k.a. PD calibrator) to make sure that they are functional expectedly.

Summary

• REFLAIR_A and POPAIR_A looked good as they showed reasonable signal gains
• On the other hand, REFLAIR_B and POPAIR_B RFPDs showed relatively large discrepancy from the expected values. I might have missed some gain factors somewhere. I will revisit these RFPDs later when I get a chance.

The RF frequency of the AM modulation was adjusted in each measurement such that the demodulated IF signal was below 50 Hz.

Calibration of the amplitude modulation depth

We recalibrated the AM laser.

The current setting of the laser was changed recently because we opened up the current driver when we thought the laser diode had been dead in the early December. Then the laser head and its current driver were sent to Rich at Caltech for his extensive testing although the laser magically fixed itself and he didn't find anything wrong. So this was the first time for us to use the AM laser which had been fixed. Because of that mysterious event, I wanted to recalibrate the laser. First of all, Yuta and I measured the power to be 2 mW with an Ophir Vega without the attenuation filter. Then we measured the modulation depth for the amplitude modulation by using a Newfocus 1611 as a reference.

The new calibration for the amplitude modulation is:

P_am =  5.13 mW x (P_dc / 1 mW) * (1 V / V_drive)

where P_dc is the laser power at DC and V_drive is the drive voltage when it is driven by a 50 Ohm source. For example, if one puts this laser to a PD which then shows a DC laser power of say 2 mW, the AM coefficient is now 5.13 mW x ( 2 mW / 1 mW) /V_drive = 10.26 mW/V_drive.

• Some details for derivation:
  • DC transimpedance of NF1611= 10k Ohm
  • AC transimpedance of NF1611 = 700 Ohm
  • Responsivity of NF1611 at 980 nm = 0.5 A/W
  • Measured DC voltage = 7.36 mV
    • => DC laser power of 7.36 mV / 10kOhm / 0.5 A/W = 1.47 uW
  • Measured AC voltage when driven by 0.5 Vpp at 10 MHz = 1.32 mVpp (measured by a 50 Ohm oscilloscope)
    • => P_am = 1.32 mV / 700 Ohm / 0.5 A/W = 3.771 uW
    • => AM coefficient is 7.54 uW / V_drive
  • Therefore the AM calibration is:
    • 7.54 uW / 1.47 uW x 1 mW = 5.13 mW x (P_dc / 1 mW) * (1 V / V_drive)

REFLAIR_A_RF9 (S1203919)

Remarks:

The signal chain is OK. The PD response is smaller by 15% for some reason.

It seems as if the transimpedance is smaller by 15% than what had been measured at Caltech (LIGO-S1203919). The cable loss from the RFPD to the rack was measured to be 0.47 dB. Be aware that the demod gain is half of the quad I/Q demodulator because this is a dual channel demod (see E1100044). The demod conversion gain is assumed to be 10.9 according to LIGO-F1100004-v4.

• Measured DC at BNC jack = 108 mV
  • DC laser power = 108 mV / 100 Ohm / 0.67 A/W = 1.61 mW
• Expected AM signal when driven by 0.1 Vpp = 5.13 mW x (1.61 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 245 Ohm = 135.6 mVpp
• Measured AM signal at the SMA jack of the RFPD enclosure = 115 mVpp
  • This is already smaller by 15%.
  • If we blame the transimpedance, it must be 208 Ohm rather than 245 Ohm.
• Measured AM signal at the rack = 109 mVpp
  • cable loss = 0.47 dB
• Expected IF signal = 135.6 mVpp x 10.9 / 2. = 622 mVpp
• Measured IF signal = 570 mVpp
  • If we take the 15% and 0.47 dB losses into account, we would expect this to be 527 mVpp.
• Expected ADC counts = 135.6 mVpp x 10.9 x 2^16 counts /40 V x 1/2 = 1209 counts pp
• Measured ADC counts = 900 counts pp
  • If we take the 15% and 0.47 dB losses into account, we would expect this to be 973 counts pp.
  • This is within 10% divation. Good enough.

REFLAIR_A_RF45 (S1203919)

Remarks:

The signal chain is healthy.

Found cable loss of about 1.5 dB. The measurements excellently agree with the loss-included expectation.

• DC laser power = 1.61 mW (the same as REFLAIR_A_RF9)
• Expected AM signal when driven by 0.1 Vpp = 5.13 mW x (1.61 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 341 Ohm = 188.7 mVpp
• Measured AM signal at the SMA jack of the RFPD enclosure = 190 mVpp
  • Very good agreement !
• Measured AM signal at the rack = 160 mVpp
  • Corresponds to loss of 1.5 dB
• Expected IF signal = 188.7 mVpp x 10.9 = 1028 mVpp
  • If the loss is taken into account, it is going to be 1028 mVpp x -1.5 dB = 865 mVpp
• Measured IF signal = 880 mVpp
  • Consistent with the loss-included expectation
• Expected ADC counts =1028 mVpp x 2^16/40 x 2 = 3369 counts pp
  • If the loss is taken into account, it should be 3368. x -1.5 dB = 2837 counts pp
• Measured ADC counts = 2784 counts pp
  • Good agreement with the loss-included model

POPAIR_A_RF9 (S1300521)

Remarks:

The signal chain is healthy.

The measurement suggests that there is loss of 1 dB somewhere. I didn't measure the cable loss this time.

• Measured DC at the BNC jack = 95.6 mV
• Estimated DC laser power = 95.6 mV / 100 Ohm / 0.67 A/W = 1.42 mW
• Expected AM signal = 5.13 mW x (1.42 mW / 1 mW) x  0.1 Vpp x 0.67 A/W x 741 Ohm = 361.7 mVpp
• Expected ADC counts = 361.7 mVpp x 10.9 x 2^16/40 counts/V = 6454 counts pp
• Measured ADC counts = 5705 counts pp
  • If we assume this discrepancy is from a loss, it corresponds to loss of 1.07 dB.

POPAIR_A_RF45 (S1300521)

Remarks:

The signal chain is OK. Though loss sounds a bit too high.

The measurement suggests a possible loss of 2.6 dB somewhere. I didn't measure the cable loss.

• Estimated DC laser power = 1.42 mW
• Expected AM signal = 5.13 mW x (1.42 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 837 Ohm = 408.5 mVpp
• Expected ADC counts = 408.5 mW x 10.9 x 2^16/40 counts/V = 7295 counts pp
• Measured ADC counts = 5391 counts pp
  • If the discrepancy is assumed to be from loss somewhere, the loss should be 2.6 dB.

REFLAIR_B_RF27 (S1200234)

Remarks:

The signal gain is bigger than the expectation by a factor of 2.3.

• Measured DC at the BNC jack = 836 mV
  • This corresponds to a laser power of 836 mV / 2000 Ohm / 0.4 A/W = 1.045 mW
• Expected AM signal = 5.13 mW x (1.045 mW / 1 mW) x 0.05 V_drivepp x 0.4 x 1000 Ohm = 107.2 mVpp
• Expected ADC counts = 18 dB x 107.2 mVpp x 10.9 x 2^16/40 counts/V = 15206 counts pp
  • I assumed that the gain factor of the diplexer (LIGO-D1300989) to be 18 dB at 27 MHz.
• Measured ADC counts = 35431 counts pp
  • This is bigger than the expected by a factor of 2.3

REFLAIR_B_RF135 (S1200234)

Remarks:

The signal gain is bigger than the expectation by a factor of 1.5

• Measured DC laser power = 1.045 mW
• Expected AM signal = 5.13 mW x (1.045 mW / 1 mW) x 0.0014 Vdrivepp x 0.4 A/W x 1000 Ohm = 3 mVpp
• Expected ADC counts = 43 dB x 3 mVpp x 10.9 x 2^16/40 counts/V = 7573 counts pp
• Measured ADC counts = 11689 counts pp
  • This is bigger than the expected by a factor of 1.54

POPAIR_B_RF18 (S1200236)

Remarks:

The signal gain is bigger than the expectation by a factor of 2.3

• Measured DC at the BNC jack = 744 mV
• DC laser power = 744 mW / 2000 Ohm / 0.4 A/W = 0.93 mW
• Estimated AM signal = 5.13 mW x (0.93 mW / 1 mW) x 0.1 Vdrivepp x 0.4 A/W x 1000 Ohm = 191 mVpp
• Estimated ADC counts = 191 mVpp x 10.9 x 2^16/40 counts/V = 3404 counts pp
• Measured ADC counts = 7803 counts pp
  • This is bigger than the expected by a factor of 2.3

POPAIR_B_RF90 (S1200236)

Remarks:

The signal gain matches with the expected value, but I don't believe this.

• DC laser power = 0.93 mW
• Estimated AM signal = 5.13 mW x (0.93 mW / 1 mW) x 0.1 Vppdrive x 0.4 A/W x 1000 Ohm = 191 mVpp
• Estimated ADC counts = 191 mVpp x 10.9 x 2^16/40 counts/V = 3408 counts pp
• Measured ADC counts = 3549 counts pp
  • This suspiciousely shows an excellent agreement with the expected one.

We've observed some burn marks on the shielding of the ETMy ring heater cables which occured sometime during the 3 prior weld sessions (May 2012, Dec 2013, Jan 2014).  The burns are on the lowest ring heater cable that laces around the test mass and makes a connection between the test mass and the PUM.  There is a burn on the right segment and the left segment.  I dug up a picture that shows that the burn on the "right" segment (as viewed from the back of the suspension) was there just after the May 2012 weld session, so that one is not new.  However the "left" cable burn is new from the Dec or Jan welding.  We did not see when this actually occured.

Filiberto tested the ring heater cable and found that all pins are operating as per spec, although he thinks pin 1 is shorting.  We are tracking down what this means (did we test it correctly, when was it last tested, is it possible that the burn is contributing to the short, even though it does not look like it is, etc.).