J. Kissel

While it has reported that the electrostatic drive is under what is expected by factors of 2, 4 and 8, repeated attempts at measuring and understanding the actuation strength of the ESD have at least garnered quite a bit of understanding on my part. The message: A factor of 8 is wrong -- a result of me misinterpreting how the actuation coefficient was calculated. A factor of 2 and 4 are still plausible, because all measurements have been made using the green ALS system, whose optical gain can vary significantly over the course of the measurement from alignment fluctuations. The latest comparisons of all H1 ETMX and H1 ETMY swept sine transfer functions report a quantitatively rigorous factor discrepancy (with uncertainty) below the expected actuation strength by factors that are indeed between 2 and 4. Many details below.

Details
-------
All published efforts to-date that attempt to quantify the actuation strength the ESDs:
aLOG             Meas Date        Optic       DOF             Drive                Bias [ct_DAC]/[V_ESD]         Response Channel [units]              Factor below 4.2e-10 [N/V^2] 
----             ---------        -----       ---       ---------------            ---------------------         ------------------------              ----------------------------
This aLOG        2014-04-28       ETMX        L         1.0-20 [Hz] Swept Sine      +125e3 / +381                ALS-C_COMM_PLL_CTRL_OUT [Hz]               2.26 +/- 0.012
                 2014-04-30       ETMX        L         0.1-10 [Hz] Swept Sine      +125e3 / +381                ALS-X_REFL_CTRL_OUT     [kHz]              3.66 +/- 0.007
                 2014-05-29       ETMY        L         0.1-10 [Hz] Swept Sine      -125e3 / -381                ALS-Y_REFL_CTRL_OUT     [um]               2.97 +/- 0.005
LHO aLOG 11929   2014-05-16       ETMX        L         11 [Hz] Sine Wave           +125e3 / +381                ALS-X_REFL_CTRL_OUT     [kHz]              8    INCORRECT ANALYSIS
LHO aLOG 12109   2014-05-16       ETMX                    Same measurement, reprocessed with better understanding                                           2    CORRECTED ANALYSIS
LHO aLOG 11676   2014-04-30       ETMX        L           Same measurement in this aLOG, reprocessed with uncertainty analysis                              4    (consistent with above)
LHO aLOG 11581   2014-04-28       ETMX        P,Y       1.0-20 [Hz] Swept Sine      +125e3 / +381                        EX Oplev        [urad]             2ish (consistent with above)

Possibly contains actuation strength, but quadrant information is too cross-coupled to obtain a pure P/Y number in terms of force:
LHO aLOG 12026   2014-05-22       ETMX   UL, LL, UR, LR  3 [Hz] Sine Wave   (+124e3 0 -124e3) / (+377 0 - 377)           EX Oplev           [urad]             Difficult to say
LHO aLOG 12027   2014-05-22       ETMY   UL, LL, UR, LR  3 [Hz] Sine Wave   (+124e3 0 -124e3) / (+377 0 - 377)           EY Oplev           [urad]             Difficult to say

Unpublished attempts:
L1/ETMX/SAGL3/Data/2014-05-30_0800_L1SUSETMX_L3_L2LPY_SweptSine.xml -- coherence deemed too poor because ALS noise too high.
L1/ETMY/SAGL3/Data/2014-05-30_0800_L1SUSETMY_L3_L2LPY_SweptSine.xml -- coherence deemed too poor because ALS noise too high.
H1/ETMX/SAGL3/Data/2014-05-15_H1SUSETMX_L3_ESD_P_2Hz.xml -- attempted to process, but got a factor 8 to 10, and gave up deciding torque was too hard
H1/ETMX/SAGL3/Data/2014-05-15_H1SUSETMX_L3_ESD_P_3Hz.xml --     ""
H1/ETMX/SAGL3/Data/2014-05-15_H1SUSETMX_L3_ESD_Y_2Hz.xml --     ""
H1/ETMX/SAGL3/Data/2014-05-16_H1SUSETMX_L3_ChargeTest_LL.xml -- attempted to take quadrant-by-quadrant data, but did not process before 2014-05-22 measurements, then gave up
H1/ETMX/SAGL3/Data/2014-05-16_H1SUSETMX_L3_ChargeTest_LR.xml -- ""
H1/ETMX/SAGL3/Data/2014-05-16_H1SUSETMX_L3_ChargeTest_UL.xml -- ""
H1/ETMX/SAGL3/Data/2014-05-16_H1SUSETMX_L3_ChargeTest_UR.xml -- ""

On the linear dependence of longitudinal Force, F on Control Voltage, V_CTRL:
We know 
F = a (V_CTRL - V_BIAS)^2
  = a (V_CTRL^2 - 2*V_CTRL*V_BIAS + V_BIAS^2)
for a given bias voltage V_BIAS.

For all of the above analysis, as a given frequency, we apply a sinusoidal control voltage at some frequency, w and amplitude V_0. As such, because of the quadratic nature of the actuator,
F = a (V_0^2*sin^2(wt) - 2*V_0*V_BIAS sin(wt) + V_BIAS^2)
           [sin^2(wt) = 1/2 - 1/2*cos(2wt) + O(4w)]
  = a (V_0^2*[1/2 - 1/2*cos(2wt)] - 2*V_0*V_BIAS sin(wt) + V_BIAS^2)
  = [(a/2)*V_0^2 + a*V_BIAS^2] - [2*V_0*V_BIAS*sin(wt)] + [(a/2)*V_0^2*cos(2wt)]
F = [        DC term         ]   [    linear term     ]   [    bilinear term   ]

Now, for a transfer function (i.e. a linear cross-correlation function), only the linear term will show up, such that
F_lin = - 2*V_0*V_BIAS*sin(wt),
or in the frequency domain, simply,
F_lin = - 2*V_0*V_BIAS.
Thus, at a single frequency, the linear transfer function coefficient magnitude between force and control voltage is

F_lin
----- = 2*a*V_BIAS
 V_0


And this is exactly the function one must use to calibrate the drive component of the electrostatic drive chain, assuming the above equation is defined where V_CTRL and V_BIAS are in units of [V] on the electrodes in-vacuum. Tracing these back to the digital drive points for the bias voltage, ct_BIAS, and for control voltage ct_LOCK, where
V_0 = G_ESD * G_DAC * EUL2ESD * ct_LOCK
V_BIAS = G_ESD * G_DAC * ct_BIAS 
where G_ESD = 40 [V/V] is the gain of the ESD driver, G_DAC = 20/2^18 [Vpp/ct] is the DAC gain, and EUL2ESD = 0.25 is the coefficient in the Euler to ESD basis transformation output matrix. This leaves the calibration to be

 F_lin
-------  = 2 * a * G_ESD^2 * G_DAC^2 * EUL2OSEM * ct_BIAS = 2.44e-10 [N/ct]
ct_LOCK

assuming a bias equivalent voltage of 125e3 [ct_BIAS], as all of the above mentioned values are quoted. As a reminder, the control voltage used in this calculation is the control voltage on one quadrant, even though you're drive all four quadrants. As a is defined above, the longitudinal force is generated by the potential difference between the ring of control voltage and the ring of bias voltage. That ring of control voltage is held at the same voltage for all four quadrants, and hence one quadrant is representative of the ring (see LHO aLOG 12109 for further description).

Calibration of each measurement's response channel newly described in this aLOG
Since three different people took swept sine TFs, with sensors each having different calibrations that were changing over time, it took a bit of work to calibrate all the transfer functions into [m].
- The calibration for ALS-C_COMM_PLL_CTRL_OUT, though it claimed to be in (green) [Hz] had not had the VCO response removed (as confirmed by a trend of the H1:ALS-C_COMM_PLL_CTRL_SWSTAT, which showed that the compensation filter in FM3, "antiVCO" was OFF during the measurement), so my calibration from [Hz/ct] to [m/ct] was
[m/ct] = L * (lambda_g / c) * zpk(-2*pi*40,-2*pi*1.6,1.6/40) * (H1:ALS-C_COMM_PLL_CTRL_OUT_DQ / H1:SUS-ETMX_L3_LOCK_L_EXC)
- The calibration for ALS-X_REFL_CTRL_OUT was similar, but this had the VCO response removed, so the only difference is the order of magnitude,
[m/ct] = L * (lambda_g / c) * (H1:ALS-X_REFL_CTRL_OUT_DQ / H1:SUS-ETMX_L3_LOCK_L_EXC)
- Finally, ALS-Y_REFL_CTRL_OUT had been calibrated graciously into displacement units, so one merely had to adjust the order of magnitude,
[m/ct] = (H1:ALS-X_REFL_CTRL_OUT_DQ / H1:SUS-ETMX_L3_LOCK_L_EXC)

Uncertainty Estimation
I've folded in the coherence to assess the uncertainty at frequency point for the magnitude and phase of the transfer function as described in LHO aLOG 12109,
meas.unc.radians = sqrt( (1 - meas.coh ./ (2*nAvgs*meas.coh );
meas.unc.m_per_N = abs(meas.tf.m_per_N) * meas.unc.radians;

Once these are obtain, I find the residual between the model and measurement, propagating the uncertainty assuming the model has no uncertainty,
residual.tf  = model.tf / meas.tf;
residual.unc = abs(residual.tf) * meas.unc.radians;

And then compute the weighted mean of each frequency point to arrive at the factor under the expected force coefficient value of 4.2e-10 [N/V^2],
residual.weightedmean = sum( abs(residual.tf) ./ residual.unc.^2 ) / sum( 1 / residual.unc.^2 )
with uncertainty
residual.weightedmean = sqrt( 1 ./ sum( 1 / residual.unc.^2 )
Now, one can justifiably argue that the reducing the obviously frequency-dependent residual down two one number, assuming that each frequency point is an independent measure of the actuation coefficient with merely statistical variations about some true mean value is not strictly correct. I agree -- there are still plenty of systematics at play that cause even a single measurement sweep to vary by as much as a factor of 2 over the frequency span of the measurement. There are several systematic errors that have *not* been accounted for in the model:
(1) The undamped dynamical model is not strictly correct at the first pitch mode at ~0.5 [Hz]. This means, that -- though the current damping filters are used in the model -- the resulting closed-loop model of the damped QUAD is not perfect. However, this should only be a discrepancy right around the resonances, and certainly not a source for an overall scale factor
(2) The optical gain of the interferometric sensors varies as much as a factor two during the 2014-04-30 H1 EX measurement (see attachment 2014-04-30_H1ALS_X_NormalizedTransmission.png). The sweep was performed from high to low frequency, and is likely the source of the drops in coherence / increase in uncertainty, especially at low frequency. This also may be the source of some apparent frequency dependence.

Welp. It's 2am. I'm impressed you read this far. Go get some coffee, you deserve it. G'morning!

There were many ETMX and EMTY ISI trips in the last two days almost all were due to me driving, most of those happened when the dtt session ended, either manually or because it reaches the number of averages, either way it trips the ISI.

There was one earthquake trip at about 5am this morning

 Chris and I were looking at the TF from ISI to OPLEV tonight and as part of that we imrpoved the diagnolization of the OPLEV, the axis was about 3 degrees off

The old matrix was +/-1s the new one is

 -0.9565    0.9565   -1.0417    1.0417
    1.0417   -1.0417   -0.9565    0.9565  (shown in figure)

  we got about a factor of 10 improvement (blue vs orange line)

   there is room for further improvement if needed

Jeff Kissel, Thomas Vo

Jeff pointed out to me today in light of the RH test this past weekend that the ITMY optical lever gain is a factor of 2 different than the ITMX optical lever.  We're inclined to trust the ITMX calibration because Keita made a pretty accurate measurement using the baffle PDs and the entire 4 km arm.  I also remember specifically changing ITMX &ETMX gains to match Keita's measurement, but I don't remember doing ITMY/ETMY. 

Anyway, Y-arm optical levers have to be checked once we get an arm again.

Dan, Corey, Keita, Hugh, Jeff

Today we started the HAM6 installation procedure outlined in T1400385.  After the north and south doors came off (and the east door was put back on), Hugh installed ISI ballast on the business end of the table while Corey checked cables.  We found we were missing two cables, to carry the OMCR-QPD and AS-C-QPD signals from the brackets on the table to the flange (cables 4 and 10, in section 6 of the procedure).  Also, we discovered a discrepancy between the flange layout document (D1002877) and the WHAM6 cable configuration (D1300122).  The flange layout correctly assigns feedthrough D5-3C to the purge air, and the WFS head cables exit the chamber through D3-2C.  According to the cable configuration the WFS head cables are going through the purge air feedthrough.

Another small discrepancy is the assignment of the OMC DCPD and PZT cables in bracket CB-1, on the top of the OMC suspension cage.  The cables are swapped from the locations prescribed in D1300122; the DCPD cable is on the second floor, the PZT cable is on the first floor.  (The connections at the flange are correct, so no worry of powering the DCPDs with the PZT drive.)  We tried to correct the bracket arrangement but discovered that the PZT cable is too short to reach the second floor of the bracket, so we left things as we found them.

We found two spare cables with Betsy for the OMCR and AS QPDs and attached those to the flange and the brackets.  The OMC suspension was moved flush against the cookie cutter, and we installed & torqued the dog clamps.  (The dog clamps are the incorrect height, but this seems to be a systemic issue.)

Now that we have finished verifying the cable connections by eye, the next steps are (not necessarily in this order):

• swap mirror M7 into a picomotor mount
• arrange tip-tilts, mirrors, and lenses in the correct optical paths (to be aligned when we get beam)
• install WFS and QPD sleds
• flash diodes, check electronics
• unlock the OMC SUS and check the OSEMs

We may need to switch between moving sleds/optics and installing ballast mass as we move through the procedure.

(Betsy, Travis, Danny, Margot)

Today we (undid some work! - ha):

- Swung the ACB back with it's swing-away hardware

- Put a TFE cap on the TCS steering mirror right in the line of foot-traffic and floor removal for protection

- Removed the stiffening braces and wedges (and ~40 fasteners) from the ITMx QUAD

- Removed 3 of the floor panels and removed the sleeve stiffening structure from the QUAD

- Started disconnection of all top stage OSEMs and cabling to lower stage OSEMs on QUAD

- Staged the QUAD hanger hardware and elevator adapter parts

- Richard swapped out my dead backup PS for the elevator - thx, RM for promptness

- Collected the witness plates/samples from BSC 1 and cleaned flooring there

Kind of thin reporting, I was in and out a lot. TVo and Hugh were in the Control Room most of the day to cover, as well.

10:30 Betsy to ITMX 
10:45 I followed soon after 
14:30 JeffB Andres to HAM6 
15:12 Dave restarting DAQ 

15:12PDT. DAQ restart. To support h1isiham5 model change and add channels to the broadcaster for DMT.

I have asked this before, but once again -

PLEASE DO NOT change the controls account settings!

This includes monitor backgrounds and keyboard layouts.

It affects every computer, not just yours, so DON'T DO IT!

Yesterday, the BSC installation arm was put on the BSC3 door.  The annulus plumbing and the cable trays prevented the flange stiffener to be attached in the correct spot, so it was rotated 1 flange-hole down.  The arm is in the appropriate place on the flange, however.  The 5-axis lift table and QUAD elevator were then mounted on the arm.

This morning, Margot and Danny took swipe samples of some of the BSC3 chamber surfaces and then cleaned the floors.  Jim locked the ISI (see his entry).  Travis and I rearranged the furniture such that we can work efficiently and then plumbed in the electrical to the elevator in prep for starting deinstall this afternoon.

I have a script which reports if  a model's filter file has been modified since last loaded, or was partially loaded (with the potential that other filters in the file have not been loaded). I'm thinking of running this at the end of every Tuesday maintenance to remind subsystem personnel if reloads are needed. Pending filter changes should be applied as soon as is possible, model restarts, power outages and RCG upgrades will load the latest filter files.

here is the output from the script for today

      h1isiham2: has modifed IIR file, investigate any prior loads
      h1isiham3: has modifed IIR file, investigate any prior loads
      h1isiitmy: has partial load, further investigation is required (last load was ITMY_ST1_T240SUBTRACT_Z Complete)
      h1hpiitmy: has partial load, further investigation is required (last load was ITMY_ISO_HP Complete)
      h1hpiitmx: has partial load, further investigation is required (last load was ITMX_SENSCOR_X_WNR Complete)
      h1susitmy: has partial load, further investigation is required (last load was ITMY_M0_LOCK_Y Complete)
        h1susbs: has modifed IIR file, investigate any prior loads
        h1tcscs: has partial load, further investigation is required (last load was ITMX_CO2_QPD_B_SEG3 Complete)
          h1lsc: has modifed IIR file, investigate any prior loads
          h1asc: has modifed IIR file, investigate any prior loads
       h1ascimc: has partial load, further investigation is required (last load was IMC_IM4_TRANS_SUM Complete)
      h1susetmy: has partial load, further investigation is required (last load was ETMY_L3_ESDOUTF_DACCT_UR Complete)
      h1susetmx: has modifed IIR file, investigate any prior loads
      h1hpietmx: has partial load, further investigation is required (last load was ETMX_ISO_VP Complete)
 

Just finished locking ITMX. I remember this from last time, but just wanted to record some of the difficulties with locking the ISI's from below, in their current configuration. The ACB is VERY in the way (it's guaranteed I bumped it a few times), so I have to basically lean out over it a little (my spine does not make the proper S shape to make this easy) and Betsy's stool is a little too tall to slide under it. It would be a little easier if the current in-chamber stool was ~1 inch shorter, making it possible to slide under the ACB. The TCS mirror is also in the way, but it's manageable to work around, don't know if I touched it, I couldn't see because my head was jammed between the chamber side and St0 of the ISI.

I have created a python script which shows the local SVN status for model code (mdl and c files used to build a model). It shows local mods and optionally shows any pending updates from the SVN repository.

The script is called reportTargetCodeStatus.py, give it -h or --help to show usage

david.barker@sysadmin0: reportTargetCodeStatus.py --help               

site is lho

usage: reportTargetCodeStatus.py [-h] [--showpending] targetname

Report status of all source code files associated with a given front end

target

positional arguments:

  targetname     the target to be reported

optional arguments:

  -h, --help     show this help message and exit

  --showpending  show code updates which are pending from the SVN repo

                 (requires kerberos ticket to be open)

david.barker@sysadmin0: reportTargetCodeStatus.py --showpending h1iscey

site is lho

                                                target:   h1iscey 

                                            showpending   Program will slow while contacting svn repostory 

                                   Model last compiled:   Tue Jun  3 10:52:58 2014 

                              Model compiled using RCG:   /opt/rtcds/rtscore/advLigoRTS-2.8.3

                                            source file             last modified svn_st Updates?

                          isc/common/models/LSC_END.mdl  Thu Nov 14 16:56:17 2013    -        -      

                        isc/common/models/STATECOMM.mdl  Thu Nov 14 16:08:57 2013    -        -      

                              isc/h1/models/h1iscey.mdl  Tue Apr 29 17:51:56 2014    -        -      

                 isc/common/models/FILTBANK_TRIGGER.mdl  Thu Nov 14 14:58:37 2013    -        -      

                                  cds/common/src/wait.c  Thu Apr 25 13:34:28 2013    -        -      

                          isc/common/models/ASC_END.mdl  Thu Nov 14 16:56:17 2013    -        -      

                   cds/common/models/SCHMITTTRIGGER.mdl  Thu Nov 14 14:50:26 2013    -        -      

                    cds/common/models/FILTBANK_MASK.mdl  Thu Nov 14 14:50:26 2013    -        -      

                      isc/common/models/LSC_TRIGGER.mdl  Thu Nov 14 14:58:38 2013    -        U      

                              isc/common/models/QPD.mdl  Tue Mar  4 09:42:07 2014    -        -      

                          isc/common/models/ALS_END.mdl  Tue Apr 29 09:52:21 2014    -        U      

                              isc/common/models/WFS.mdl  Wed Dec 11 19:13:12 2013    -        -      

                       isc/common/src/RtCommunication.c  Thu Nov 14 13:19:02 2013    -        -      

Plotted the dust trends for the past 24 hours (00:00 to 00:00)of dust monitor #5 in the Beer Garden. This cover the time period when the doors were removed from BSC1 and BSC3.  

Betsy, Sheila, Keita, Arnaud, Thomas

Here is a snap shots of the current alingment offsets. This alingment was checked quickly this morning, both of the arms are flashing green so the ITMs are within a urad or so of alinged. 

We noticed that the ailngment of ITMY was off by about 8 urad in pitch from the saved offset, this seems to be because turning on and off the ring heater changes the ailngments.  Attached are trends of the OpLevs durring the ring heater stress test this weekend, the itms moved by 2-5 urad in yaw, and both moved by about 30 urad in pitch. The third screenshot shows how the pitch changed as the ring heater power cycled.

Dan H. completed setting up of the HAM6 QPD sled yesterday.  With he & Keita both happy with the Dan's mode matching measurements, the Sled wrapped up and bagged.  Before doing this, positions of optics were measured (with a ruler +/- 1mm).  Here are distances measured:

• 133mm:  Edge of Sled -> L201 (center of lens mount)
• 223mm:  L201 -> L202
• 41mm:  L202 -> M203 (front surface)
• 88mm:  M203 -> QPD1
• 111mm:  M203 -> M202
• 63mm:  M202 -> M201
• 282mm:  M201 -> QPD2

Photos of the HAM6 QPD Sled are located here.

The WFS Sled, QPD Sled, Fast Shutter Beam Dump, and a bag of hardware/dog clamps are all in totes in the Optics Lab and ready to be payloaded on HAM6 (most likely early next week?). 

NOTE:  Still missing the Fast Shutter!  Still being designed/manufactured??