(see WP #6332)

Did a few "on/off" states for Robert S. so as to compare spectra while IFO in low noise.  He OK'd the continued running of these pumps during the intended bake-out of pressure gauge PT180 located on BSC8's dome.  As is, the apparatus is ready to go with the exception of the gauge electronics which remain connected and energized.  I am ignorant as to the impact, if any, of removing this while it is energized.  I've been told that this gauge has an in-vacuum PCB that limits the bake temperature to 80C at the CFF and I can just see myself going through the bake exercise only to have to vent and replace the gauge because I had "popped" the internal electronics by removing the external electronics while energized!  Spoke with Patrick T. who is only familiar with the Beckhoff end of things, left msg with Richard M. who might know more pertaining to the hardware.  Mfgr. tech support is not available via phone during off hours etc....  

As such, I am leaving PT180 exposed to the site vacuum volume (YBM) and the pumps etc. running.  The locally mounted turbo pump is isolated from PT180 via a closed metal valve and its exhaust valve is open to the supporting pumps located on the LVEA floor.  I will attempt to start the actual bake-out on Friday - hopefully by then I will have determined how to de-energize the gauge or discounted the concern of removing the external electronics while energized.  

Until we put in a more permanent solution next week, over the holiday weekend here are the instructions to allow the operator to disallow hardware injections from running, say in the event of a GRB.

From the SITEMAP MEDM, on the X-Arm line, select the CAL pull down and press the PINJX button

You will see the CAL_INJ_CONTROL MEDM for the x-arm.

The part we are interested in is the Transient signals portion in the centre of the screen. Open the  filter modlue screen by pressing the TRANSIENT related display button.

The filtermodule can be in one of two states depending upon whether a transient hardware injection is currently runng (not a high probability occurance).

If an injection is not running (the most probable scenario), the GAIN will be 0.000. In this case, turn OFF the output ON/OFF button to the right of the LIMiT switch.

If an injection is running the GAIN will be 1.000, set the GAIN to 0.000 (it will ramp down over 2 seconds) and then turn OFF the ON/OFF button.

At this point wait for the ring-down period of time (nominally one hour).

To permit hardware injections, turn ON the ON/OFF button (in the unlikely event an injection is running, either wait for it to finish or set the GAIN to 0.000 again)

TITLE: 11/24 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: Ed
CURRENT ENVIRONMENT:
    Wind: 24mph Gusts, 21mph 5min avg
    Primary useism: 0.15 μm/s
    Secondary useism: 0.51 μm/s
QUICK SUMMARY:

• Came in to a NLN H1 with PEM Injectors (Anamaria/Robert) working with Kyle (who was on the floor at BSC8's VAC pumps).  They then handed over to Sheila...
• Sheila working on H1. 
• BRSx was in a rung up state & we are letting it ring down.  So, will leave SEI_CONFIG in WINDY_NO_BRSX state until Jim looks at it (tomorrow?).
• Will return to PEM Injection work after they have "lunch".

Robert, Anamaria

We did a test of the RGA at the X end station. Its peaks seem to be at around 79.5 Hz and 158.7 Hz. We were not able to see a change in DARM BUT the 80ish Hz bump was not there to begin with. We did blast a line at that frequency and saw no coupling to DARM. The 79.5 Hz peak lines up suspiciously with the center of the usual bump. Quite unlikely, but to be sure that's not it we could still do an off test when the peak is present in DARM.

Last night we did a similar test in the corner station. We didn't have sensors super close so the peaks are not as obvious but they seem to be at 75 and 158.5 Hz. This also had no effect on 80 Hz bump.

16:40: Krishna out to Biergarten

16:43 Karen into H2 building

17:03 Kyle back from EY

17:07 Green arms aligned: recentered X arm as per oplevs and started from there. Got a good alignment but still not maximum power. Got closer to maximum by tweaking TMS a µrad or two.

17:17 re-started VERBAL ALARMS

17:21 Karen out of H2 building

17:30 Keits to end stations to check on  unsed ADC channels

17:45 IA complete. Beginning lock sequence

17:46 Bubba taveling to ends and mids. X -arm first.

18:12 Bubba done with x-arm and heading to Y mid. He'll stand down from EY visit due to current locking.

18:16 Lock loss at close beam diverters. HAM6 ISI tripped.

18:30 Keita called. He's finished at EX and headed to EY

18:45 NLN - switched manually from NOISE_TUNINGS

18:53 King Soft onsite

18:55 Richard back

19:21 a2l script

20:05 Keita is back

21:52 Alarm at CP4

22:10 did remote manual CP3 overfill - 20seconds

22:15 Kyle to MY to visually inspect the remote overfill.

22:41Kyle back

23:50 Robert and Anamaria back from EX

It looks like PEM is also doing an injection on BRSX as well as the broader IFO, it's very rung up. I have disabled the damping on it temporarily, we shouldn't use it for a little while. If the damper table runs too hard for too long it can get out of position, which is kind of annoying to fix. I'll check on it tomorrow. For now, the SEI_CONF should be left in WINDY_NO_BRSX. This state is currently using some narrow band sensor correction at ETMX (that bypasses the BRSX) to help with the microseism

While I was using conlog, I got distracted by the changing ODC bits for ASC and OMC, which seem to be constantly changing because of some thresholds that probably haven't been set recently.  I quickly updated them. The attached screenshot shows all the changes I made.  

I set some things that I think should be the same so they are matching (ie, I set CHARD thresholds to match DHARD thresholds, CSOFT to match DSOFT, AS_A_DC and AS_B DC now match but I set the maximums to be just under the ADC saturation level)

20:47 at Robert's request, I have closed reamining beam diverters except for POP. 

21:06 Anamaria is at EX. BRS has been turned off.

Dr Effler reported to me that she has reverted the -.2 Pit offset that Sheila set recently back to +.2. This resulted in a 400µrad shift in IM4.

I have created a new troubleshooting guide for H1, in preparation for O2.  It is available at G1602280 (too big for alog, so won't add it here also).  Attached here is the overview page that in the document has clickable links to each section.

My vision for this is that it is a go-to document when things aren't working as smoothly as they should be.  I try to provide specific instructions on what to do, but also enough information that Detector Engineers, Operators and anyone else can start looking deeper and debug problems on their own.  Text throughout the guide is clickable, so that you can jump to the section that you need. 

I encourage others to add to the document, or point me to well-written wiki pages / alogs with detailed instructions so that I can add to the document.  For example, both the PI and violin mode damping "instructions" in the guide actually just point you to the very well written wiki pages on those topics.  There are 19 sections so far, but I'm sure that I've missed some, and that others will come up, so please let me know or modify the document yourself if you find something!

As of now, H1:LSC-[XY]_EXTRA_AI_[123]_OUT_DQ are in the science frame at 2k, but nobody remembers what they are.

I went to the end stations and found that H1:LSC-X_EXTRA_AI_1 and H1:LSC-X_EXTRA_AI_2 were connected to green REFL A FET demodulator I and Q monitor. Same thing for Y.

Since we haven't looked at these for a long long time, I removed these cables from the DSUB breakout. There's still one cable attached to DSUB breakout which is for Ethercat-frontend interface, but this is not EXTRA_AI channel.

For the moment the output of these channels are turned off to compress the data size. Next Tuesday these are removed from the frame.

We'll also remove jitterFF signal from the frame as we're not using that feature.

Krishna

Summary:

1. Closing the valve for the vacuum can of cBRS makes it very sensitive to pressure through an unknown mechanism. With the valve open, pressure coupling is not visible.

2. cBRS sees signficant ground tilts at wind speeds of ~20 mph, which are coherent with ITMX Stage 1 rY sensor but not very coherent with ITMY ground seismometer. As we suspected, ITMX sees larger ground tilts than the ITMY seismometer. For some peculiar reason, the ITMY seismometer seems to be in a null zone for tilt. This is the reason it works well for sensor correction for the corner.

Details:

As discussed in my SWG log last week, cBRS sees excess ground tilts below ~50 mHz which are not expected given it's 'd' value. It's 'd' value can be inferred from it's translation coupling visible as the height of the microseism peak along x-direction.

1. I wondered if there was some other effect that was causing the increase in the cBRS signal below ~50 mHz. In an effort to understand this, I closed the valve to the vacuum can. I had hoped to supress air pressure/density changes in the beam-path which would give a phase shift signal through index of refraction effect. To my surprise, the pressure sensitivity got signficiantly worse as seen in the first attached file - PZTControl_ValveClosed.png. The second file cBRS_PressCorr_ValveClosed.pdf shows the time trace of the scaled pressure, angle and temperature signal with some scaling. The pressure correlation is quite clear.

Two possible ways it could have gotten worse are - a) mechanical effects, such as pressure change producing stress on the vacuum can base producing tilt etc and b) stress on the vacuum can base affecting the fiber feedthrough.

Since this was clearly worse than before, I reopened the valve fully.

2. The third file (cBRS_Quiet.pdf) shows data under low wind speeds. I have shown cBRS angle data, the inferred tilt from cBRS, the PEM tiltmeter (fancy bubble level) and the ITMY seismometer acceleration/g (to convert to angle). The next page shows coherence between cBRS angle and Stage 1 rY, ITMY STS-X and Stage 1 X. The coherence at the microseism is due to the translation coupling.

The last file shows the same set of data under wind-speeds of ~20 mph. Note that regardless of the cBRS transfer function, the signal above resonance is trustable and shows a large increase in tilt which is similar to what we see at the end-stations. The PEM tiltmeter and the ITMY STS see an increase as well but they are smaller than the cBRS tilt in the 80-100 mHz region by a factor fo ~3. The coherence plot also shows signficiant broadband coherence between cBRS and Stage 1 rY (except at the microseism, likely due to an incorrect scale factor for the T240). The shape of the inferred tilt looks odd below ~50 mHz and indicates an incorrect transfer function. It looks like there is an additional systematic effect that I'm missing (I think it is not temperature or pressure so far). I'll continue to investigate.

It looks like we had another incident of the POP90 power changing, (circled in the striptool screenshot) similar to what Stefan described in 31181.  Is this still a problem with the demod as RIchard found the first time?  If its only an intermittent problem with the POPAIR 90 demod, we probably don't need to worry about fixing it before O2 because that is jiust a monitor and won't be used if we are able to close the beam diverters for the run.  

Detchar question: 

Did we have RF45 glitches around these times?  The times are roughly 16:26, 16:30, 16:36 and 16:42 Nov 19th local time, which is 0:26, 0:30, ect Nov 20th UTC time.