Today I "meticulously" helium leak tested the Vertex RGA and couldn't find any external air leaks.  This is unfortunate as it now confirms the worst case which is that the suspect calibration gases are the likely source of our contaminates (including air).  

Some history -> After the initial bake out of this RGA, The scans seemed typical until exposed to the calibration gas(es) (see https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=27100 and https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=27078) after which, they looked dirty.  Hoping to still utilize these already installed leaks, I did a second bake (nominal 200C) only, this time, with both leak's isolation valves open and heated to 100C for the entire hot "soak" period before then being isolated - just prior to the temperature ramp down phase.  Following this second bake I had a new problem - I couldn't get anything but a "flat line" trace on the RGA, as if the ionizer was working but the mass filter (RF) section wasn't.  In addition to the standard "tapping" of the hardware, I opened the Kr cal-gas to get a burst and to confirm the symptom.  I eventually discovered that a small piece of aluminum foil was shorting out some pins in the RGA's electronics socket.  Once removed, the RGA worked fine with the exception that the scans looked "dirty" and had the presence of air.  What would they have looked like had I fixed the problem before exposing the baked RGA to the Kr? 

I now feel that these NOS calibration gases installed at the end-stations and now at the Vertex ought to be removed, discarded and replaced with proven "clean" ones.  To this end, I plan on temporarily installing their replacements (and the to-be-installed ones slated for the mid-station RGAs) on one of the VBOs to take a look at them before they get installed on the site RGAs. 

	The vacuum MEDM web screen shot software was restarted to pick up the latest vacuum MEDM screens following today's work on h0vacmr (See alog 27364).

Looked at the mode matching of the high power oscillator beam into the pre-modecleaner
situated in the diagnostic breadboard (DBB).  Moved ML2 closer to the pre-modecleaner
and things did not appear to change much.

Keita told me that an interlock prevents operation of the DBB, which I will look into
tomorrow.  It might be that I left something disconnected - although I don't think I
did.

Sheila, Haocun

We are trying to compare the amplitudes of 90MHz and 36MHz modulations at the AS port.

1. Using gpib connected to Agilent 4395A to measure the spectra of photo-current signals. The measurements are 1E-7 V/rtHz for 36MHz, 6E-8 V/rtHz for 45MHz, and 7E-8 V/rtHz for 90MHz. 
   All three signals are at the similar level.
2. Using RF detectors to check the input signal of demodulator, which are -18dBm for 36MHz, -12dBm for 45MHz, and -28dBm for 90MHz. 
   The 90MHz is lower, about 1/4 of 36MHz.
3. From measurements coming out from the demodulator are: 2943 counts for 36MHz, 2557cnts for 45MHz, and 17cnts for 90MHz (after being divided by gains).
   The factor drops to < 1/100.

These results are not consistent with each other, and we will check by changing the whitening gains and the demodulator.

WP 5889

I updated the code on h0vacmr to change IP1, IP3 and IP8 to gamma controllers. Since I still had time before the end of maintenance I also took the opportunity to add IP13 (HAM1) and IP14 (HAM6). IP13 is using one controller of a dualvac. IP14 is using a gamma controller.

The only hiccup was that the conversion from Amps to Torr for the gamma controllers was getting truncated to an integer. I fixed this in the library.

The names changes for IP1, IP3 and IP8 are attached.

I have updated the medm screens.

1. Ran field cables for the ITM ESD install. This required working on top of HAM3 to dress cables. Cables in the CER were dressed into SUS-C6.

2. Installed railing and shelves for the high voltage ESD supplies (CER Mezzanine)

3. Ken ( K Electric) ran power cable from CER Mezzanine to the SUS racks in the beer garden

4. Started installation of NGN electronics in CER Rack OAF-C1

5. Looked at power distribution for the Op Lever in LVEA. Power supply in CER was powered on, and began testing drop off points on the floor, correct voltage output.

Gerardo, Kyle, Chandra

Replaced HAM 11 & 12 annulus IPs - both were spent. While at it, we re-checked the inner o-ring leak to see if it changed since many door bolts were tightened after pumping down diagonal volume. We vented the annulus space to atmosphere. Diagonal volume pressure rose an order of magnitude. Attached are pressure plots from annulus vent on 3/24 and from today.

Annulus space quickly pumped down to 1e-6 Torr with hung turbo carts and now is pumping purely on annulus IPs.

HAM 12 reads 2 mA (HAM 11 wiring on CDS)
HAM 11 reads 5 mA (HAM 12 wiring on CDS)

Ross, Tega, Evan

Last night we were using the ESD drivers on ETMX to control a mechanical mode at 15217Hz. We used a similar method as mentioned in our previous aLOG 27153 to track the mode but now this signal can now be used to drive the ESD to damp these modes. The ESD quadrants that are used for the damping of this mode are the lower left and upper right and the damping signal is applied positively to the lower left and negatively to the upper right. 

For this particular case the mode that we were trying to damp was within ~1Hz of another line around 15218Hz which may be a mechanical mode relating to another test mass. This makes it difficult for the line tracker to stay locked onto the mode if it’s amplitude is lower than the neighbouring line.

The time series plot shows the amplitude output from iwave line tracking. Before the green line the tracker settles on the pre existing line at 15217Hz. A gain of 1000 is then applied to the damping signal which exites the mechanical mode. After around two minutes a gain of -1000 is then applied to the the damping signal which damps the mechanical mode. However after the mode has been significantly damped the line tracker then changes the frequency that it is monitoring to the neighbouring line so it is no longer damping the same line. The spectrogram of OMC data underneath the time series shows how the line amplitude grows and then declines as the gain is altered. 

We are hoping to repeat this test to identify more of these modes. This seems to be a good indication that this process should work if it was this mode being excited by a parametric instability. 

Landed cables for ion pumps IP13 and IP14, per WP 5897.

IP13 is located on HAM1 and its controller is a dual type (Negative polarity).

IP14 is located on HAM6 and its controller is a LPC type from Gamma Vacuum (Negative polarity).

QUAD Master model change WP5899

Kiwamu, Betsy, Dave:

Kiwamu made a changed to QUAD_MASTER. All four quad models were rebuilt and restarted (h1susitm[x,y], h1susetm[x,y]

CAL model changes WP5894

Kiwamu, Dave:

All three calibration models were changed, built and restarted (h1calcs, h1calex, h1caley).

Vacuum Controls change for Mech Room IP1,3,8 WP5889

Patrick, Dave:

Beckhoff code for h0vacmr control of IP[1,3,8] changed. New EPICS database, autoBurt.req and DAQ ini files generated. This entails a channel name change, I have changed the running minute trend files. Still need to cover archived files.

Update NDS2 client code. WP5886

Jim B:

nds2 client code updated, please see earlier alog.

DMT Broadcaster channel change

Dave:

Changed the duotone channels in H0BROADCAST0.ini to reflect LLO names (use IN1 rather than OUT channels in filtermodule). This change went into effect when the DAQ was restarted.

New SUS PI models

Tega, Ross, Dave

New h1susitmpi, h1susetmxpi and h1susetmypi models were installed.

ADC card installed in h1oaf0 IO Chassis for NGN model

Dave, Jim:

We installed a 6th ADC card into h1oaf0's IO Chassis. This is a long-term-temporary card (will be removed post O2) which will provide the h1ngn model with 30 sensor channels. Powering down h1oaf0 meant that the following models were restarted: h1ngn, h1pemcs, h1oaf, h1tcscs, h1odcmaster, h1calcs.

The h1iopoaf0 model was edited to add the 6th ADC.

The h1ngn model was modified to use the new ADC.

In the IO Chassis we decided to locate the ADC between the DAC and DC power supply rather than group it with the other 5 ADC cards, This minimized the models which needed to be modifed to just 2.

Check 18bit DAC card in h1susb123 which failed its autocal

Dave, Jim:

Following the reboot of h1susb123, h1iopsusb123 reported that the first 18bit DAC card had failed its autocal. Today we restarted h1iopsusb123 three times, and each time the first DAC is reported to have failed autocal.

h1asc filter file loaded

Dave:

h1asc was showing a modified filter file. Investigation shows another repeated-filters problem (DHARD this time). I performed a full load.

J. Oberling, T. Schaffer

The PR3 and SR3 oplevs have been moved from the stand-alone DC power supplies on loan from the EE shop to a power supply installed in the LVEA CER.  Both lasers came back up without issue but will need a few hours to thermally stabilize again, as we had to open the coolers to turn them off and on.  This completes work permit #5895.

J. Oberling, T. Schaffer

We re-centered all active H1 optical levers (ITMx/y, ETMx, PR3, SR3, BS, HAM2) except for ETMy (which was done by Ed and I last week).  This completes work permit #5795.

WP 5894, 5899

related alogs: LLO log 26126, LHO log 27336

In order to update the online calibration model and some related infrastructure, I have recompiled, rebuilt and restarted the following front end models this morning.

• h1susitmx
• h1susitmy
• h1susetmx
• h1susetmy
• h1calcs
• h1calex
• h1caley

All of them are burt-restored to 7:10 AM this morning. The changes I made on h1cal* are already summarized in alog 27336. As for the change on h1sus*, it is only quad suspensions' master library, QUAD_MASTER.mdl, that was modified; I have replaced a calibration oscillaltor on the L3 stage with a new fixed phase oscillator.

Summary:
A new, better inverse actuation filter has been made for the x-arm Pcal, but it has not yet replaced the old filter. This was constructed using knowledge of the Pcal OFS-AOM gain coefficient (see LHO alog 27155), the suspension model, and models of the digital/analog AI components. The AI components had to be approximated since the injection model runs at 16k. Also, the actuation function delays couldn't be included in the filter, so all waveforms using the attached actuation function or using the inverse actuation filter should assume a timing advance of 225 us. Another aLOG will be posted once the new filter is in place.

When including this timing shift, the new actuation function/inverse actuation filter match the real values to within 5% in magnitude and 5 degrees in phase up to 2 kHz. Above 2 kHz, the deviations from the true actuation function are significant due to the approximations chosen for the analog/digital AI filters and a rolloff filter being applied.


Details:
The continuous wave hardware injections would like to use the Pcal actuation function instead of an inverse actuation filter for O2. Meanwhile, the transient injections will continue to use an inverse actuation filter. The actuation function is nominally modeled as follows:
PCALX_EXC --> IOP-15 --> 16k-64k AI(D) --> DAC (V/ct) --> ZOH 7.5 --> AI(A) --> OFS --> AOM --> N/W --> Norm. SUS --> 1/f^2 --> DC SUS (m/N) --> 1/L (h/m) --> strain
Legend:
IOP-15 = 15 us delay from the IOP
16k-64k AI(D) = digital anti-imaging filter (using the new RCGv3.0.2 filter, see LHO alog 27173)
DAC = digital-to-analog converter
ZOH 7.5 = zero-order-hold, 7.5 us delay
AI(A) = analog anti-imaging filter
OFS = optical follower servo
AOM = acousto-optic modulator
N/W = power-to-force coefficient = 2*cos(theta)/c (Note that this does not include rotation-induced errors, with 1-sigma uncertainty of 0.4%, see LIGO-L1600018)
Norm. SUS = normalized suspension transfer function model which has been multiplied by zpk filter with 2 zeros at 1 Hz
1/f^2 = zpk filter with 2 poles at 1 Hz
DC SUS (m/N) = suspension force-to-length "DC" coefficient
1/L (h/m) = inverse of the mean arm length

The OFS-AOM system has a wide-bandwidth (UGF ~50 kHz) and a gain of 0.0923 W/V for H1 ETMX Pcal (this is watts impinging on the ETM per volt of drive sent to the OFS, LHO alog 27155). The SUS file used is in the SUS repository:
/ligo/svncommon/SusSVN/sus/trunk/Common/SusModelTags/Matlab/quadmodelproduction-rev7652_ssmake4pv2eMB5f_fiber-rev3601_h1etmx-rev7641_released-2015-08-07.mat
However, in order to construct an *inverse* actuation filter, some of these components cannot be included because a delay would turn into an advance (breaking causality). In addition, the model runs at 16k, so the inverse AI digital filter must be approximated. The high frequency components of the inverse actuation filter need to be rolled off using additional filtering. Thus, the *inverse* actuation filter model is constructed as follows:
strain --> L (m/h) --> 1/DC SUS (N/m) --> f^2 --> 1/Norm. SUS --> W/N --> 1/[OFS * AOM] --> 1/AI(A) approx --> DAC (ct/V) --> 1/AI(D) approx --> Ellip. rolloff --> 3 7kHz poles --> PCALX_EXC
Here, there are two approximations made: the analog/digital AI filters are modeled to roughly match the magnitude (see comparisons in figures 1 and 2), as well as removing the IOP and ZOH delays. Note that two rolloff filters are used to suppress high-frequency content, a 3rd-order elliptic filter and 3 7kHz poles. The phase error in the approximations is accounted for with the expectation that waveforms using this inverse actuation filter will need a timing advance of 225 us.

The analog AI approximation is one zero at 5160 Hz and 2 poles at 7100 Hz (e.g., [5160:7100,7100])--see figure 1. The digital AI approximation is 4 zeros at 7000 Hz, and 2 complex pole pairs (e.g., [7k,7k,7k,7k:pair(4300,30),pair(7000,50)])--see figure 2. The elliptic rolloff filter is given by the Matlab function myellip_z2(6900,3,.4,10,10)--6900 Hz knee frequency, 3rd-order, 0.4 dB ripple, 10 dB stopband, and zQ of 10.

The final Pcal actuation function and comparison to the real value is shown in figure 3 with the delay included, and figure 4 is the inverse actuation function with the advance included. Figure 5 shows the impulse response of the inverse actuation filter (no delay included).

The attached H1PCALXactuation.dat file is the actuation function sampled every 0.125 Hz.

Code that produced these results is located in
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O2/DARMmodel/Scripts/pcal_actuation_function_quack.m

Next steps: replace the old inverse actuation filter, move the inverse actuation filters from the PINJ_HARDWARE bank into the PINJ_TRANSIENT bank so that the CW injections (which will use the Pcal actuation function manually) will not pass through the inverse actuation filter.

Summary:

I analyzed the HWSY measurements from a ~28 hour period around the 18th of May during a long lock segment and lock/unlocked transitions. There are systematic shifts in the measured defocus which can only be coming from some alignment coupling. There is evidence that the delivered CO2 laser power may be more than the CO2Y power meter suggests.

Our attempts to maintain the total lens using the CO2 laser power during locked/unlocked transitions are currently ineffective because the CO2-induced thermal lens response is not calibrated correctly.

Analysis:

There was as a period of a 7 hour lock last week. I extracted the RAW HWS images corresponding to this period (t0 = 1147500000 to t0 + 1E5s) from the directory: controls@h1hwsmsr:~/framearchive/h1hwsmsr/ITMY/1147500000/. These were centroided offline to determine the measured defocus (a proxy for H1:TCS-ITMY_HWS_PROBE_SPHERICAL_POWER which should be running online). The offline calibration included:

• dividing by a factor of 2x to convert from double-pass to single-pass
• dividing the raw spherical power measurement by the nominal magnification (7.5) squared to convert to the spherical power at the ITM.
• The zero value was reset such that defocus = 0 around t = 70 minutes

I also extracted the SIM estimates of defocus (defocii?) from the self-heating (H1:TCS-SIM_ITMY_SUB_DEFOCUS_SELF_OUTPUT) and CO2 laser power (H1:TCS-SIM_ITMY_SUB_DEFOCUS_SELF_OUTPUT). All three of these time series are plotted below.

And a zoomed version of the first 600 minutes is shown below:

A few points to note:

• There are unexplained (and unphysical) jumps in spherical power after the system loses lock around 550 minutes. My working hypothesis is that alignment changes during attempts to reaquire lock are somehow coupling to this HWS measurement.
• There are transient glitches in the spherical power every so often. I don't know the cause of these
• The measured drop in spherical power from the HWS is much larger than the expected drop in the SIMulation (from lowering the CO2 laser power)

If I double the expected CO2 response and create a new channel that is the sum of the double CO2 lens and the SELF heating (and reset the zero value of this channel), I get a result that is much closer to the measured lens in the HWS.

Additionally:

As you can see in the images attached to aLOG 27047,  that CO2Y table is capable of delivering a maximum of ~2.3W off the table (when the CO2Y laser is running at 57W). The CO2X table is capable of delivering a maximum of ~5.5W off the table (when the CO2X laser is running at 59W). There is no functional difference in the design of the two tables (expect that Y is a mirror image of X). The possibilities for this difference are:

• Optical (we may be clipping the beam somewhere on the CO2Y table)
• Electrical (We're somehow losing signal between the H1:TCS-ITMX_CO2_LSRPWR_MTR power meter and the ADC input electronics).
• Software (we have an unexpected calibration difference between the tables). Scanning L1TCSCS.txt and looking at the gain settings in the filter banks for the X and Y power meters and comparing the EPICS GAIN channel for these filter banks rules out this possibility (barring some hardcoded difference in the SIMULINK model).

And: the maximum power that could be delivered from this table on 26-Jan-2016 was around 5.5W.

Therefore: Given all this information, I suspect that the CO2 laser is somehow reading back less power than it is delivering (or, if you like, delivering more power than we're expecting).

TO DO:

• Measure the CO2 laser power directly on the table with an independent power meter
• Measure the CO2 central heating thermal lens with the HWS with the IFO unlocked and no other changes to the IFO alignment
• Determine why we see systematic changes in the HWSY defocus apparently with IFO alignment changes.

With the elevated intensity noise currently being injected into the interferometer, we can passively make an estimate of the CARM pole frequency.

The attachment shows the transfer functions that take interferometer input power to transmitted arm power (as measured by the four end-station QPD sums) with the interferometer locked at 22 W. There isn't good coherence around the CARM pole frequency itself. However, if we normalize each signal to RIN, this fixes the dc value of the transfer function at 1. Hence, the magnitude of the slope is sufficient to extract the CARM pole.

At 10 Hz, the transfer function is 0.0631, which implies a CARM pole of 0.63 Hz. There is about 1.5 % uncertainty from the spread in the values from the four transfer functions, and about 2 % uncertainty from the drifts in dc intensity for the four QPD sums during the measurement period. Together that makes 2.5 % uncertainty. There may also be additional uncertainty from the whitening and antiwhitening of the QPD signals.

If we assume an ETM transmissivity of 4 ppm, an ITM transmissivity of 1.45 %, a PRM transmissivity of 3.0 %, and 50 ppm of loss on each test mass, we expect a CARM pole of 0.64 Hz (see T1500325).

Obviously a superior method is to take a driven transfer function that has good coherence at and around the CARM pole frequency, and to use the phase information to make a true fit.