Koji, Craig

Koji has the idea that maybe our IMC FSR is not exactly equal to our RF 9 modulation frequency, and this is responsible for additional 9 MHz RF AM seen by Sheila and Jenne.
So today Koji and I moved the modulation frequency around.  We used the double modulation technique for finding the FSR by looking at the 24 + 9 = 33.178 MHz peak and trying to minimize it.  
We found that the frequency was already pretty well tuned.  We moved it around from 9.100230 MHz and found the best rejection of 33.178 MHz peak at 9.100225 MHz.  Larger movement of the modulation frequency (on the order of 10s of Hz) resulted in much higher 33.178 MHz peaks.

Then we tried repeating Sheila and Jenne's OMC 9 MHz locking test.  The results are plotted below.
The first attachment shows the OMC DCPD spectra and RF AM monitor spectra, each one appropriately calibrated into RIN, for different RF9 modulation slider values.  We see a moderate (factor of 2) win from going from +27 dB to 23.4 dB, otherwise 9 MHz RIN remains about constant.
The second attachment shows the effect of changing the 9 MHz modulation frequency by 5 Hz.  The 9 MHz RIN seems to be independent of our frequency move. 

We note that the move from 23.4 dB to 27 dB on the RF9 slider actually does increase the modulation depth, since the OMC DCPD SUM increases when this is done.  Koji suspects that his measurements from before measuring the response of the EOM suffered from broadband saturations spoiling the linear response.  Going above 23.4 dB on the 9 slider is still not recommended.
We moved the modulation frequency back to 9.100230 MHz and left it there.

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We also injected a line into the EOM driver for the 9 to calibrate the REFL A 9I pd into units of RIN.  It seems that REFL A 9I is a pretty poor RIN sensor relative to the OMC and RF AM monitor. (attachment 3)

TVo, Craig, Danny

We'd hoped that by changing the SRC mode we could move away from co-resonating of higher order modes that could be propagating through the ifo (9MHz higher order modes from the OMC and the increased contrast due to mismatched absorption). 

What we looked at:

• We trended the DARM cavity pole, POP18, power recycling gain, arm transmission, range, and OMC trans.  

IFO configuration: 

• At nominal low noise
• At a steady thermal state
• The OMC PZT offset was at 44.8 volts
• DARM offset was at 14.8
• Turned on the SR3 heater to 1 watt @ 3:32:00 UTC and 3 watts @ 4:02:00  UTC

Result: 

• The increase in SR3 heating decreased the cavity pole frequency and increased optical gain (please see first attached figure).

Modeling of the SRC is currently in the works to compare with our result. 

This evening we made some small tweaks to the ASC:

• We had a lockloss earlier today where DSOFT pitch rang up. We have added DSOFT_P engagement back into the guardian in ENGAGE_SOFT_LOOPS (for the last ~week we have only been using CSOFT_P). I also put the 20dB gain increase for DSOFT pit in LOWNOISE_ASC.
• We found CHARD Yaw rang up during the lock. We increased the gain from 3 to 6 and this seems to have fixed the problem. Craig checked the CHARD coherence with DARM and it does not seem any worse. I put this extra gain in the LOWNOISE_ASC guardian state.
• With these CHARD and DSOFT settings we've been locked for ~4 hours so far.
• I also increased the amplitude of the low frequency dither lines when they are first turned on, in PREP_ASC_FOR_FULL_IFO.

After we did the calibration sweeps, I tweaked the DARM offset slightly, looking at the DARM BLRMS and the coherence between the OMC QPD and the OMC DCPD sum (see attachment). I didn't see a change in the coherence between the QPD and the DCPD sum. During this test the 9MHz modulation was 20.4 dBm. I got excited about the change in the DARM BLRMS from 100-400Hz and 500-1000Hz (5 and 6 respectively) while changing DARM offset, seemingly finding a local minimum with a offset of ~16 (normally we operate at ~14.8). I'm not sure why there would be such a minimum. I've left the darm offset at 14.8.

Ana Lam, Madox McGrae-Menge, Yasmeen Asali, Emily Calamari

We worked on analyzing DRMI lock acquisition the past couple weeks with Sheila. We downloaded HI:GRD-ISC_LOCK_STATE_N data from August 2018 through January 2019 and examined the transition from Acquire DRMI 1f (101) to DRMI Locked Prep ASC (102) specifically calculating the duration and outcome of DRMI locking attempts. The scripts we developed can be found here.

The attached plot shows the past five months of DRMI locking attempt durations averaged by hour and colored by outcome, where "Success" indicates a successful transition from state 101 to 102 and "Failure" denotes any time the system reverted to a lower state. The vertical line marks December 18th when the TCS settings were reverted back to 30W, and we observed a statistically significant difference between the distribution duration means between the two time intervals (see github scripts for U-Test details).

TITLE: 01/19 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning

CURRENT ENVIRONMENT:
    Wind: 5mph Gusts, 4mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.42 μm/s

INCOMING OPERATOR: None
SHIFT SUMMARY:  locking, in NLN
LOG:

• 18-01-19 17:10 Robert to EY and then EX
• 18-01-19 18:55 Vanessa to MX to get palets
• 18-01-19 18:55 Nutsinee to SICT6
• 18-01-19 19:30 Robert back
• 18-01-19 20:07 Peters commissioning meeting 20:00-21:00
• 18-01-19 20:08 LHO meeting about Maintenance 21:00-22:00
• 18-01-19 20:30 Nutsinee back from ISCT6
• 18-01-19 22:22 Niko and Damitri to EX to set up for Pcal for Tuesday
• 18-01-19 22:56 Jaime rebooting h1calinj
• 18-01-19 23:41 Nutsinee to LVEA ISCT6

I have added some monitor and BLRMS channels to SEIPROC for the restarts this coming Tuesday. The BLRMS channels are on all of the OAF_SUSPOINT channels, this should be a useful quick monitor of any changes to seismic configuration effect on cavity lengths.

I've also added some sensor correction LOCAL_DIFF dq channels. SEIPROC calculates common mode ground motion, that gets sent to all of the chambers, allowing us to subtract off the large common ground motion leaving a smaller differential signal that we can use for sensor correction. Each chamber calculates this differential signal as a test point, but we weren't saving this data in the frames. It's easy enough to reconstruct, but it would be good to have a record of the input used, and we don't really need every chamber saving this data. Unfortunately, doing it in SEIPROC means we can't get the endstation off axis LOCAL_DIFF channels, but I got the other 7:
H1:SEI-EQ_ETMX_X_LOCAL_DIFF_DQ 
H1:SEI-EQ_ETMX_Z_LOCAL_DIFF_DQ
H1:SEI-EQ_ETMY_Y_LOCAL_DIFF_DQ
H1:SEI-EQ_ETMY_Z_LOCAL_DIFF_DQ 
H1:SEI-EQ_ITMY_X_LOCAL_DIFF_DQ 
H1:SEI-EQ_ITMY_Y_LOCAL_DIFF_DQ 
H1:SEI-EQ_ITMY_Z_LOCAL_DIFF_DQ 

J. Kissel

We've had a really tough time keeping the IFO locked over the past week, which has made taking full interferometer calibration measurements difficult. In anticipation / hope that things might get better over the long weekend, here're the location of pre-tuned sensing function sweeps in case anyone gets a good lock stretch:
    /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/FullIFOSensingTFs/
        2019-01-16_H1_PCAL2DARM_TF_5t1100Hz_3min.xml
        2019-01-16_H1DARM_OLGTF_5to1100Hz_14min.xml

To run:
(0) Make sure the IFO has thermalized, letting things settle for ~30 minutes after powering up. The measurements MUST be run in the same, well-thermalized lock stretch.
(1) Request NLN_CAL_MEAS from the ISC_LOCK guardian state (this turns off all calibration lines).
(2) Run each sweep in series; run the PCAL sweep first b/c it's quicker. (You can "cheat" a bit if you're impatient -- when the PCAL gets past ~10 Hz, you can start the DARM OLGTF)
(3) Save the templates with a new date, YYYY-MM-DD but in the same folder.
(4) Request NOMINAL_LOW_NOISE, which will turn the calibration lines back on.

As is indicated by the file names, both measurements together should take about 20 minutes.

Per Q1800019, I visually inspected H-GV11 and H-GV15 on Dec. 18 to verify that the spindle nut and lock washer are present. Was not able to inspect torque setting without fall protection.

Per Q1800019, I visually inspected H-GV12 on Dec. 19 to verify that the spindle nut and lock washer are present. Was not able to inspect torque setting without fall protection.

RX/RY motion is typically a limiting factor for ISI suspension point motion. This is because we are limited in lowering the blends by sensor noise, but it might be possible to make different compromises to reduce SRCL motion between 1 and 10 hz, possibly allowing lower SRCL loop gain to reduce SRCL to DARM coupling.

On the HAM ISI, the current RX/RY blends are designed to minimize the blend gain peaking below 1 hz and to avoid injecting rotational GS13 noise into the horizontal loops below .1 hz. This limits how quickly the CPS blends  can roll off above 1 hz, thus limiting the absolute isolation. I've tried to come up with a blend to improve performance above 1 hz, but compromises need to be made to do that. In October, I tried running these blends for a couple of days on HAMs 4&5 RX/RY.

First attached plot shows some spectra comparing a lock on Oct 19 last year (with the "improved blends") to a lock a couple days later (with the low gain peaking blends). The top plot is a reconstruction of the SRCL cavity using the ISI gs13s, which I did by multiplying each optics OAF_SUSPOINT motion timeseries by the appropriate suspension model to estimate each optic's motion (using lsim in matlab), then adding the timeseries together using the coefficients from the OAF_SUSPOINT cavity calculations.  The second plot compares CAL_CS_SRCL for the two locks, this is supposed to be um, but that is clearly wrong, the cavity can't be moving ~1m, so I'm not sure what the calibration is there. The third plot is the SRCL drive on SRM M3. All 3 plots show some improvement over above 1 hz with the more aggressive blends on HAMs 4&5 RX/RY. 

The second attached figure is a bode plot that compares are couple blends for the HAM ISIs. The first two lines (ntchrll...) are the blends that we use currently, which have low gain peaking, but are CPS noise limited, pretty much everywhere. The next two lines (between350...) are the more aggressive blends I tried in October. They inject more GS13 noise at low frequency into the horizontal loops, but didn't keep us from locking, so maybe it's okay. The last three lines are a more aggressive blend I would like to try, guided by the improvements I was able to get by changing blends. The low frequency stuff is pretty similar, the gain peaking is roughly the same, but I gave up above 10hz CPS roll-off to try to get as much improvement as possible between 1-10hz. 

It would be interesting to know if the scattering seen at EY is new. Last October I did a quick set of injections to look for major problems - because of limited time these were speaker injections instead of shaker injections and did not probe much below 30 Hz. We did not see any coupling in October. Kara and I went out last night to reproduce the October injections to see if we would have seen vibration coupling if it were at the same level as it is now. The figure shows that we probably wouldnt have noticed the current level of coupling with the injection made in October.

We are set up so that a shaking injection can be made using H1:PEM-EY_GDS_1_EXC. I suggest a standard injection using a bandpass of 1-100 Hz and 50,000 counts for studies to reduce coupling by moving the RMs, offsetting the dither, etc. I have to leave, but Kara is familiar with the system.

Robert, Kara

Koji, Craig

We became interested in Sheila and Jenne's 9 MHz RIN measurement, and so set out to measure a more complete spectrum of the 9 MHz demodulated REFL PD noise to gain some perspective on the 9 MHz amplitude modulation transmitted through the IMC.

First we shuttered the PSL and measured a full suite of dark noise spectra.  
Then we requested ITMs and SRM misaligned, PRM aligned, and 8 watts of input laser power.  This gave us 30.97 mW on REFL A LF and 28.52 mW on REFL B LF.

This is not a direct comparison of 9 MHz RIN as measured by Jenne and Sheila; their measurement is capable of picking out a single sideband, while ours is the usual carrier and sidebands beatnote.  We'll think about the comparison of each measurements' RIN.

I put a camera on the HAM2 West door, which looks at CW1, the back side of the wedge, which is carefully aligned to shoot through the IM1 tower.

This week I developed a procedure to use PRM with a single bounce, to move the REFL beam on CW1, and and look for clipping.  The procedure revealed that when PRM is in it's aligned position plus an additional 200urad in yaw, there's an increase in light on the baffle, consistent with the REFL beam starting to clip.  With PRM at -1000urad, the REFL beam is clearly seen on CW1 to thr right of the main input beam.

Using the image and a beam path simulation I wrote in matlab, I've measured the main input beam to be between 2mm and 3mm from center.

I need to adjust my HAM2 top camera to improve the view of the IO Faraday output side, which is planned for next Tuesday, in order to realign through the Faraday, to correct the mis-centering at both the input and output Calcite Wedges.

compared to the main input beam, which I've used to identify the location of the main input beam on the wedge.  A diagram and images attached.

Koji, Craig

- We ran the RF9 modulation depth change test Sheila asked us to do.  Koji will post an alog about those results.

- Koji had me lock the OMC with PZT2 at only 2 volts, rather than the usual ~40 V, for +9MHz 9th order HOM considerations.

- We measured the PRCL OLG after full thermalization at high power, and got a 30 Hz UGF.  This seems much lower than what was reported by Jenne a week ago.

- I carried the laptop in with me as I made my way down to the PSL racks.  
This time, I was able to make it without causing a lockloss, but when I got there the SR785 GPIB was gone, and when going to get it from the squeezer bay, while walking between HAM2 and HAM3 I killed the lock.
The area directly in front of the door in the LVEA, between HAM2 and HAM3, is the most sensitive to walking around, according to IMC_F.  Stepping on the lower tier floor directly inside of the LVEA door seemed to produce the largest response in IMC_F, including during my first excursion to the PSL racks.

- We reached nominal low noise again, but lost it within ten minutes, probably due to some CHARD, DHARD pitch ringup.  

- We reach NLN a third time, and this time held it for two hours, during which I was able to get to the PSL racks and measure all CARM spectra.  We eventually lost lock due to a super slowly growing ASC 0.9 Hz oscillation (lost lock about an hour after the ringup started).

- Had to readjust TMSY alignment in pitch significantly to get the guardian to continue locking in FIND_IR.

We are still trying to nail down our non-linear gain measurement. Here's a comparison between two methods:

1) MIT method:

nlg = ((sqrt(pMax/pMin) + 1)/2)^2

2) ANU method:

nlg = pMax/pUnamp

pUnamp is seed transmission measured outside nlg region as I scan the OPO cavity (temperature set to ~51C, green blocked). Which is an unamplified seed power.

I took nlg measurement with data from StripTool and oscilloscope. The result are consistent within 10% between the two methods and two devices. 

Pump input to coupler: 20mW

Pump reflected (OPO off resonance): 2.7 mW

Seed input to coupler: 1 mW

StripTool (IR trans PD): max = 0.0063 mW, min = 0.0019 mW, DN = -6.8e-5 mW

Scope (IR trans PD): max = 142 mV, min = 47.6mV, DN 8mV

Seed trans unamplified: StripTool = 0.003 mW, Scope = 76.4 mV

Craig, Georgia, Danny, Sheila

We have re-tuned the SRCL feedforward for 30 W interferometer configuration. The updated feedforward reduced SRCL coupling to DARM from 60Hz to 500Hz (driven measurement shown in final attachment).

We measured the transfer function from SRCL to DARM without feedforward, and from the SRCL-FF path to DARM, using templates found here:

/opt/rtcds/userapps/release/lsc/h1/scripts/feedforward/

We then used Craig's ipython notebook to fit these transfer functions and calculate the feedforward filtering required to cancel SRCL noise in DARM. The notebook is found here:

/ligo/home/craig.cahillane/Git/Feedforward/SRCL2DARMfeedforward.ipynb

This notebook uses iirrational to fit the transfer functions. We added some human tweaking to the fit to minimise the resonant peak at ~8Hz. First attachment shows the data (blue), iirrational's fit (orange), and the human-modified fit that was implemented in the feedforward filter (green). Note that the fit to the phase of the TF is not good below 60 Hz, so perhaps there is room for iterative improvement on these filters.

The second attachment shows the old SRCL-FF filter (Nov7) compared to our new filter (Jan15).

The final attachment shows the SRCL to DARM coupling reduction: yellow is DARM (and SRCL) with no excitation, blue is with the old feedforward, purple is the new feedforward.

A new h1calinj model has been installed on the h1oaf1 machine.  This model will hold all front-end injection handling logic, including the injection EXC test points, under the channel prefix "H1:CAL-INJ_".  The existing injection handling code in the h1calex model ("H1:CAL-PINJX_") has been left as is for now to facilitate transitioning and testing.

The first two attached images are of the top-level contents of the new h1calinj model, and of the contents of the "INJ" CAL_INJ_MASTER2 library part that contains all the core logic.  The top of the latter shows the main injection signal flow.  The two "CW" and "TRANSIENT" filter banks at the upper left hold the EXC inputs and calibration filters for the continuous-wave (CW) and transient (TRANSIENT) injection inputs respectively.  The outputs of the two modules are summed and the overall "MASTER" output goes through an output switch ("MASTER_SW"), and then finally a switch ("END_SW") that determines which of calex or caley receives the injection signal ("H1:CAL-INJ_{X,Y}" via cdsIPCxRFM).  Below the main signal path is logic to determine the presence of signals at various points in the injection path, and bundle that info into a single status word ("STATUS_OUT").

IPC receivers for the INJ_MASTER output sent from h1calinj (H1:CAL-INJ_{X,Y}) were added to the h1calex and h1caley models.  EPICS and acquired test point monitors of the received signals were also added.

NOTE: a single 2**14 Hz, 61 us cycle delay will be added to the injection path because of the IPC needed to carry the signal from the vertex to the ends.

The new acquired fast channels are:

• H1:CAL-INJ_CW_OUT_DQ
• H1:CAL-INJ_TRANSIENT_OUT_DQ
• H1:CAL-INJ_MASTER_OUT_DQ
• H1:CAL-INJ_STATUS_OUT_DQ
• H1:CAL-INJ_X_OUT_DQ
• H1:CAL-INJ_Y_OUT_DQ

The STATUS channels (the H1:CAL-INJ_STATUS_OUT_DQ uint32 fast channel and the H1:CAL_INJ_STATUS slow channel) have the following bits:

0. MASTER
1. CW
2. TRANSIENT
3. CBC
4. BURST
5. DETCHAR
6. STOCH

A value of zero (0) indicates no signal of the specified type is present, and a value of one (1) indicates the presence of the specified signal.

The h1calinj model also holds the "TINJ" EPICS status bits, nominally set by the INJ_TRANS guardian node.  NOTE: the "H1:CAL-INJ_TINJ_" EPICS records were previously hosted by the ext_alert_ioc.py soft IOC running on the h1fescript0 machine.  The records were removed from the soft IOC and the process was restarted.

The final image attached is a new MEDM screen CAL_INJ_CONTROL2.   All functionality and status bits in the h1calinj model, and the monitors in h1calex and h1caley, are exposed.

As mentioned above, all the existing INJ infrastructure remains in place.  We leave it up to the INJ group to update the INJ_TRANS guardian, the psinject process, downstream monitors, etc.  We would like to schedule the removal of the old INJ infrastructure as soon as possible,

Visually inspected GV4 and found it is equipped with a retaining nut and anti-rotation locking washer. Torque setting on pulley nut as seen in attached photo.

Again I tapped on HAM 7 annulus ion pump but the red overload light remained on, so I turned off the power supply.