I checked to make sure the line and the BP matches. Changing the phase both on the main PI medm screen and on the damping filter doesn't make a different. The PLL green light is on but Shelia mentioned that PLL is not actually locked and I don't know how to make it locked (some other modes with PLL green light indicator also have red PLL lock status). I also tried to zero the gain as Sheila suggested.

TITLE: 11/02 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC

STATE of H1: Nominal Low Noise/Commission

OUTGOING OPERATOR: Ed

CURRENT ENVIRONMENT: Wind: 16mph Gusts, 13mph 5min avg Primary useism: 0.03 μm/s Secondary useism: 0.29 μm/s

QUICK SUMMARY: Before Stefan left he asked me to make some TF measurement. So I'm going to spend some time doing that before setting the intent bit. Locking went smoothly.

After today's changes to the PMC servo, which included increasing the loop gain, we noticed a familiar bump around 4.2kHz in DARM.  Lowering the PMC gain from 16dB to 0dB made the bump smaller in DARM (see images).  Given the coherence with REFL9, it seems that this is coupling through frequency noise.

We also made a small exploration around the already good PMC input beam alignment.  This didn't have much impact, but it revealed that small changes in the alignment can change the input offset to the PMC servo.  That is, the offset which maximizes the PMC throughput can be changed with small alignment tweaks. Using this effect, we made a 0mV input close to optimal (see second image).

J. Kissel

In order to improve the uncertainty on the parameters the lines are measuring, I've adjusted the line heights of a good fraction of the calibration lines. I'll leave them in like this overnight, and see if we get the expected improvement in the uncertainty (especially as reported by the front-end). 

Line              Freq     Former     New
PCALY             36.7      750       500
                  331.9     2900      5000
                  7.9       20000     5000

ETMY UIM          33.7      60        180
ETMY PUM          34.7      27        81

Note the reduction of the 7.9 and 36.7 Hz modes. We don't always increase line heights ;-).

• the initial alignment mentioned in the mid-shift summary wasn't wihout alignment of IM3 (~200urad in YAW and ~80urad in PIT) and PRM (mostly YAW an a little PIT)
• the first NLN lock was brioken by commissioners moving optics around.
• Email sent to Bubba about orange water in OSB toilet close to labs.

Since the cdsutil avg function kept failing, we replaced it by the average of 20 ezcareads - 0.2sec apart.

This was done in a separate state - PREP_TR_QPD_SUM_OFFSET.

Admittedly not the most aestetic fix, but it seems to work reliably.

Notes:

0) A2L gains of order two are getting suspicious, because it essentially means some coils are shut off.

1) ITMY_Y2L was always large (~-2) , but since 10/29 7UTC it is even bigger.

2) ITMX_Y2L also got big (~2) on 10/29 7UTC

Not sure what to make of this...

PSL101 Yellow alarm at 6:59UTC 300NM

I added a PRM_SPOT_MOVE state similar to the PR2_SPOT_MOVE and PR3_SPOT_MOVE states (see alog <a href="https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=30754">30754</a>)

It allows moving IM3 to adjust only the PRM spot position.

To use it, just like with the other two scripts, turn off the PRC1 ASC loops.

The only issue with this state is that IM3 is very close to saturation already, so there is not much room.

J. Kissel, M. Evans

Matt over heard me talking to Yuki about PCAL actuation and asked the time-honored question of whether the current "large" calibration lines were causing any non-linear impact in the DARM sensitivity. I've not proved this suspicion wrong in a few months, and not after starting the huge 7.9 Hz SRC detuning tracker line, so I figured I'd oblige. 

As such, I've turned off the PCALY lines during this lock stretch at 05:51:42 UTC, and restored them at 06:11:00 UTC.
(Note, for those who are looking behind me, we were running A2L for the majority of the time between reaching nominal low noise and starting this test. Commissioning also broke the lock just after the test.)

The current line amplitudes do not adversely affect the DARM sensitivity in any other way than expected. Also for the record BNS range was identical between ON vs OFF as well.

Since we didn't have the interferometer today, I stiched together some previous measuremnts of frequency noise and transfer function. In particular:

alog 30610: Out-of-loop frequency noise sensors (POP9, REFL45, POP45): Caveat: The alog only accurately calibrated them at high frequency - I suspect the sensor disagreement at low frequency is a deviation form the simple scalar calibration.

alog 29893: Transfer function in m/W (the template also has m/ct). Caveat 1: This was measured at 50W - need it at 25W, Caveat 2: The transfer function is known to vary, see alog 30440.

That said, I can ignore all the caveats for now (until we redo the measurments at 25W) and use the three out-of-loop frequency noise sensors to predict the DARM contribution. Specifically, I cast POP9, REFL45 and POP45 into REFL9 counts using alog 30610, and then apply the transfer function from aLog 29893. I woudn't trust the result better to about a factor of 3 - mostly because we don't have an accurate frequency noise calibration of those sensors at low frequencies. But the result is in the attached plot.

Clearly, this needs to be redone with more precision. But if this theory holds up, then what we are seeing is REFL9 sensing noise (due to scatter or donut jitter or something else), being imprinted on frequency noise, coupling to DARM.

Over the weekend I wanted to try modulating PR2 in yaw, pitch, and length, as well as CPs, etc. to see the effect on shaking-enhanced scattering peaks. I haven’t got a chance to do more than the first of these yet but the attached plot shows that the peak in DARM did modulate with a slow yaw injection at PR2, while nearby parts of the spectrum did not. The plot suggests a better parking place, but the stationarity of the optimal yaw needs studying.

• After PSL team came out of the enclosure Jenne and I began initial alignment procedure
• Jenne tagged out and Jeff K joined me at ops. After a little difficulty with SRC. we began full locking only to break at PREP_TR_CARM
• Stefan found some bad offsets in the TR_CARM step, so he created a new step to mitigate.
• Locking made it to ENGAGE_ASC_PART2, at which time Sheila concluded that the arm alignment needed some attention.
• Another initial alignment is being done at this time.
• DMT seems to be locked-up
• Environmentally quiet with uSei trending back downward

For both PMC locking and injection locking, servo board and field box board were modified as per FRS 6500 (FRS id=6500 and alog 31047).

After the modified boards went in, we removed the 20dB attenuator on the PSL rack RF patch panel for 35.5MHz for PSL EOM.

This seems bump up the ILS and PMC length locking optical gain by about a factor of 10 (for ILS the analog gain was changed to compensate).

We also remeasured the demod phase for ILS and PMC length locking. For ILS we didn't see much change (1ns), but PMC was significant, we ended up changing 3ns, i.e. 39 degrees for 35.5MHz.

Demod setting are shown in the first two pictures, ILS (first attachment) and PMC (second). Third picture shows that the ILS is on the left bottom of the four delay lines, and PMC is on the right bottom.

The fourth picture shows the OLTF of PMC that is pretty close to the one we have now. Note that UGF is much much higher than before simply because of the optical gain and the demod phase (might have to change).

Unfortunately the floppy for SR785 failed, so we'll remeasure the ILS loop gain again tomorrow.

Robert called from EY to info me that he was going into the VEA area near the BRS

WP6288 Dave, Jim:

We cleanly power cycled h1iscex and its IO Chassis this morning between 11:45 and 12:06 PDT. We were not able to reproduce the slight offset on an ADC channel (see attached). Note this channel is actually only seeing ADC bit-noise, so the offset is in the micro-volt level.