The ISC signals have been added to the ETMY HEPI model. Changes have been committed to the svn. The model has been successfully compiled and installed. We should be ready to offload.

J. Kissel, T. Vo

We received the daughter boards (D1001631) which take place of the Binary I/O connection for control of the Oplev Whitening chassis (D1100013), specifically the internal ISC Whitening board (D1001530). For each of the 4 channels, the whitening board has 7 independently switchable states:

(1) 24 dB (x16)  Gain
(2) 12 dB (x4)   Gain
(3) 6 dB  (x2)   Gain
(4) 3 dB  (x1.4) Gain
(5) [10:1] Whitening
(6) [10:1] Whitening
(7) [10:1] Whitening

where my notation for zeros and poles is [z:p]. So, Thomas and I installed the daughter on H2 SUS ITMY's optical lever, and explored the raw voltage spectra of the QPD segments with each of the settings on (well, most of them). I attach the results.

To fill out the legend:

RED: This was the state that the optical levers had been in, with no control (i.e. the BIO input spigot was left open).
BLUE: Daughter board installed, but with all switched flipped to OFF. This is the same as red -- good. That means the chassis doesn't *need* the daughter board to be functional, and the board sits at its default state (no stages engaged) with nothing plugged in. Fair enough. 
GREEN: 12 dB Gain stage turned ON
BROWN: 4 dB Gain stage turned ON
MAGNENTA: One [10:1] whitening stage turned ON
CYAN: Two [10:1] whitening stages turned ON
BLACK: All Three [10:1] whitening stages turned ON

Note that we tried switching on the 24 dB gain stage (alone), as well as having both 6 dB gain + One [10:1] whitening stage. Both of these configurations saturated the ADC.

Assuming the amplitude of the signal represents a reasonably quiet time, we decided to leave the chassis in the CYAN state, with two [10:1] whitening stages and no gain, to give some head room for noisy day time activity, or when the ISI is not functioning as well as it is now. Because we now have whitening in the chain, these filters have been compensated for in the $(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG# banks (in addition to the -1 discussed in earlier logs).

One thing to note: the ADC noise floor (visible in the unwhitened spectra, above ~40 Hz) is 5 uV/rtHz.

Calibration Details:
--------------------
Here's a schematic of the QPD signal chain: 

                                                                                          +--- $(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG1_IN1
      +-------+                                                                           |
Up ^  | 1 | 3 |      +-------------------+      +-----------------------+      +-----+    +--- $(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG2_IN1
   |  |---+---| ---- | Whitening Chassis | ---- | Anti-aliasing Chassis | ---- | ADC | ---| 
   |  | 4 | 2 |      +-------------------+   ^  +-----------------------+      +-----+    +--- $(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG3_IN1
      +---+---+                              |                                            |
                                             |                                            +--- $(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG4_IN1
                                        equivalent
                                   voltage measured here

(staring at the face of QPD, as though you were an incident laser beam). 

We used DTT to measure the above listed channels, which were then calibrated using the 16-bit ADC calibration of
40 / 2^16 [V/ct] = 6.1e-4 [V/ct]
hence, as I point out in the diagram, we're effectively measuring the output of the whitening chassis since the AA chassis has a gain of 1 and no frequency response.

For the record (and long overdue), here is the payload weight of the SUS components on BSC8:

44 lbs = 8 x 5.5 lbs for Vibration Absorbers
~60 lbs  = FMy Stays
~2 lbs = FMy Sheer Plate dampers
10 lbs  = Cabling   
2 lbs = Cable Brackets
3 lbs  = Ring Heater + Brackets + Cables
266 lbs = ITMy QUAD Upper Structure
531 lbs = ITMy QUAD Lower Structure
44 lbs = QUAD Sleeve
2 lbs = QUAD sleeve wedges
341 lbs = FMy SUS (weighed in at 394lbs with the 53 lb LSAT attached prior to install)
55 lbs = 1.26 lbs X Dog Clamps (33 long + 22 short)

TOTAL = 1360 lbs = 641 kg

J. Kissel, T. Vo

Now that we're sure we completely understand the calibration of the two optical levers, I've installed Thomas' calibration in the gain field of the $(IFO):SUS-$(OPTIC)_L3_OPLEV_[PIT/YAW] filter banks. The resulting calibrated spectra are attached.

Several things to note:

- After proper whitening, I believe that the ITMY optical lever is measuring real motion out to the limit of the spectra I show (hundred of Hz).
- I think the "real" motion, above ~5 Hz is dominated by structural resonances of the lever launcher/receiver, and probably other various not-test-mass-motion things.
- The low-frequency (< 5 Hz) motion of the ITM (in both Pitch and Yaw) is just about what has been predicted / measured by other independent methods.
- ETMY *does not* have his whitening control board installed yet, so there's no whitening on the signal and is hence dominated by ADC noise, especially in Yaw.
- The ETM Pitch spectra looks also roughly at the amplitude expected, and similar to the ITM Pitch spectra, but 
- The ETM Yaw signal appears orders of magnitude below ETM Pitch, as well as ITM Yaw, assuming the only feature in the spectra (at 0.43 Hz) is real motion. Why? The spot needs centering, that's all -- it currently shows it's off in the weeds somewhere mrads away from center.


Tomorrow: 
- Center the spot on the ETM QPD
- Install whitening control board, explore parameters a bit (just to see if it's different from ITMY -- my guess is that it won't be)
- Remeasure.

Almost there....

P.S. For future reference, once the calibration is installed (which it is now for H2 ITMY and H2 ETMY), the following channels are calibrated into microradians:

$(IFO):SUS-$(OPTIC)_L3_OPLEV_PIT_OUT_DQ
$(IFO):SUS-$(OPTIC)_L3_OPLEV_YAW_OUT_DQ

The Arm locks again, with the spectra attached (first attachement). The positive message is that the ISI performance has greatly improved. The drop at 0.5 Hz is the Quad pendulum  mode. At higher frequencies (above ~0.6 Hz) we are most likely dominated by frequency noise.

We optimised the SHG temperature, so there is more power in the green (an extra 10mW). This is meant to remidy the power fluctuations we were seeing when we drifted further away from our nominal VCO frequency. We will see if that is the case. I reduced the CMB-B input gain by 3dB (down to -17dB!)  to make up for the increase of light on the diode, but I forgot to measure the UGF of the PDH loop (nominal 11 kHz).

Local damping to M0 and L1 on both Quads are engaged, and the length feedback is of loaded to the ETM M0. The power drops over the longer time scale (>1 hr), is most likeli becasue I haven't inserted the decoupling. I tried to decouple it in pitch without much succes.

In the spectrum, the features at 2.75 Hz and 4 Hz are seen in the Reference Cavity transmitted power, and are imposed on the laser in the end station.

The problem we currently having is that the VCO seems to jump every ~8 min, when it reaches 40.2 MHz (about 600 kHz from the nominal 39.6 MHz), seen in the second attachment. The cavity seems to stay lock and all keeps running 'smoothly'. Due to this jump I was not able to do more than 4 averages in the spectrum.

The cavity has been locked for over an hour, which is an improvement. I unlocked the cavity before I left.

On request ... the traces are taken at 1) 27/7/2012-02:47:57, 2) 19/7/2012-7:17:00, 3) 19/7/2012-6:40:00 and 4) 19/7/2012-7:40.

Attached are plots of dust counts > .5 microns in particles per cubic foot.

Bram, Alberto, Elli.  We set the green laser doubler crystal temperature to maximise the green laser power output.  The laser diode current was 1.725A and the 1064 laser crystal was 42.05 degrees C.  We varied the doubler crystal temperature and measured the power output.  Attached is a plot of these measurements.  The green laser power was maximised when the doubler crystal temperature was set to 34.37 degrees C.

When the doubler crystal temp was 34.37 degrees C:

(with 1.725A input current, 42.05 degrees C crystal temp)

-The laser power output was measured at 41.9mW

-GR_PWR_MON read 8400 counts

-REFL_PWR_MON read 15500 counts, and we measured 1.22mW, 4.8V, and a gain setting of 20dB at this PD.

The work done on ITMY in the last few days has been duplicated to ETMY. It was very straight forward. The exact same blend filters are being used on both units and provide similar isolation. See attached plot where:

- Red curve is ITMY, BSC-ISI control off  
- Blue curve is ETMY, BSC-ISI control off
- Green curve is ITMY, BSC-ISI control on
- Brown curve is ETMY, BSC-ISI control on   


The data can be found in the DTT file seismic/BSC-ISI/H2/ETMY/Data/Spectra/Isolated/ETMY

Contol off: UTC time 23:52:36, 15 averages, df=50mHz
Contol on:  UTC time 23:45:51, 15 averages, df=50mHz



---------------------------------------------------------------------------

For our records, I am posting the details of what was done to implement this on ETMY:


1) Damping Loops

Our Damping loops were DC coupled. A DC offset was visible when turning the loops on. I added:
- two zeros at DC
- two poles at 25 mhZ: pair(0.025,65)

To do that:
- I modified the cutoff filters in Step_5_Damping_Loops_ST2_LHO_ISI_BSC6.m
- Run Step_6_Damping_Loops_ST1_LHO_ISI_BSC6.m
- Run Step_7_C2D_Damping_Filters_LHO_ISI_BSC6.m
- Updated the foton file


2) Output Filters

Installed the new output filters, which includes the low pass at high frequency to limit the "glitches" when the control is turned ON.

For that:
- Run aLIGO_BSC_ISI_Output_Filters.m
- Run aLIGO_BSC_ISI_Filters_Digitalization.m
- Updated the foton file


3) Blend Filters

- Created the following folders:
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H2/ETMY/Scripts/Complementary_Filters
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H2/ETMY/Filters/Complementary

- In Complementary_Filters, copied the ITMY complementary filters file:

Complementary_Filters_Stage12_750mHz_2012_07_25.m
Complementary_Filters_Stage12_250mHz_2012_07_25.m
Complementary_Filters_Stage1_100mHz_2012_07_25.m

Run these three files that create the complementary filters, store them in .mat files saved in Filters/complementary.


4) Control_Scripts

Step_8_Blend_Filters_LHO_ISI_BSC6.m:
- Modified Step_8 to load the good complementary filters
- line 41 and 42 modified the blend_frequency value and index (commented the changes in the m file)


Step_9_C2D_Blend_Filters_LHO_ISI_BSC6.m:
- added teh continuous/digital filters comparison
- modified it to generate the filters necessary to make the blend switching work (T240 and NXT)

Run Step 8 and Step 9 for each of the three blend filters
Updated the foton file

Committed the changes to the svn

 

Jeff K. , Thomas V.

Below are the calibration parameters for the H2 ITMY Optical Lever:
        Slope          Y-intercept
Pitch [ 580.41229822  -11.51774017]
Yaw  [ 689.70532274  -13.3345144 ]


And here are the calibration parameters for the H2 ETMY Optical Lever:
         Slope           Y-intercept 
Pitch [ 1666.80728788   -33.14694715]
Yaw  [ 1727.67131855     23.41350328]

Both sets of calibrations were attained via the same process of moving the QPD along a translation stage and measuring the output signal.  All four sets of slopes are in units of radian*meters.

Optical lever QPD's analog signals from each segment/quadrant come into the ADC in numerical order (1, 2, 3, 4) where the segments are defined as

   +-------+
   | 1 | 3 |  ^
   |---+---|  | This way up
   | 4 | 2 |  |
   +---+---+

(staring at the face of QPD, as though you were an incident laser beam). The QUAD MASTER model absorbs these signals as channels

$(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG1
$(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG2
$(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG3
$(IFO):SUS-$(OPTIC)_L3_OPLEV_SEG4


However, up until this model change, the top level ITMY model had been re-ordering these signals as

Analog Signal    ADC Channel      SEG#
1                1_0              SEG2
2                1_1              SEG1
3                1_2              SEG4
4                1_3              SEG3


I have now re-ordered them in a sane fashion, as the ETMY had already been ordered:

Analog Signal    ADC Channel      SEG#
1                1_0              SEG1
2                1_1              SEG2
3                1_2              SEG3
4                1_3              SEG4


The updated model,
${userapps}/release/sus/h2/models/h1susitmy.mdl
has been committed to the repo, and I've recompiled, reinstalled, restarted, and restored H2SUSITMY.

The Assembly Validation testing of HAM-ISI Unit #6 is complete. HAM-ISI Unit #6 - Assembly Validation report was posted under the DCC, and validated. We can now store this Unit in a container.

HAM-ISI Unit #7 will be the last HAM-ISI built at LHO. Assembly is approching completion. Assembly Validation testing will follow.

Reports regading the Assembly validation of previous units at LHO are available in the DCC:
HAM-ISI Unit #1 - Assembly Validation
HAM-ISI Unit #2 - Assembly Validation
HAM-ISI Unit #3 - Assembly Validation
HAM-ISI Unit #4 - Assembly Validation
HAM-ISI Unit #5 - Assembly Validation

This morning we adjusted the 0.4mm roll out of the MC2 lowest stage via rolling the optic in the sling.  We were able to take the roll error from 0.4mm on each side to 0.003mm error, well within the 0.25mm guideline.

We reset the M3 stage AOSEMs and are now back to running TFs of MC2.

For the record, I've done the following:

  ~ $ cd /opt/rtcds/userapps/release/sus/
sus $ svn up

The "common" folder was what I was specifically looking to make sure was up to date (and now the folder has all the new quad changes, as well as the CD_STATE_MACHINE updates), but the update also received a whole bunch of (other) site specific stuff.

 We received a text message from the alarm handler this morning regarding a signal associated with GV16 at the XMID station. After reviewing the signal in question we realized that this signal had fallen to zero on July 20 from a nominal 1ma  (scale of 1-10 mA)

This looks like the normal failure mode of the annulus ion pump power supply and will be investigated and hopefully repaired (depending on replacement parts) next week.

Signal is HVE-MX:GV16_II339

The tripleteststand had the One-stop cable and cards (between the computer and the I/O chassis) replaced yesterday in an effort to solve the mystery of the models freezing and the cards in the I/O chassis becoming invisible.  The x1sushxts27 model was started Wednesday 7/25 at 14:06 PDT and is still running this morning.  

I have taken the calibration data and analyzed it. The plot of the linear response curve is attached.

I used a polynomial fitting program in python to get these numbers.  This should give you the conversion from volts to micro-radians.

           Slope            Y-intercept
Pitch   [  1.01902201e+06   8.42886118e+00]
Yaw     [  9.83122943e+05  -1.19329010e+01]

HAM-ISI Unit #6 was balanced, and CPS readouts were within acceptable range, on 07/03 when we left it for long TF measurments. When checked this morning, CPS readouts featured an offset of approximately +/-3000 counts:

There is no drive/offset on MEDM channels.

Coil drivers were turned off. The CPS readouts remained unchanged.

CPS interface chassis were turned off, and then turned back on. The CPS readouts remained unchanged.

Dataviewer plots are attached. They show the drifting of the CPS readouts.

We experienced high temperatures over the last few days.