Since there seem to be some confusions about which PD has what kind of analog filtering and sent to which channel, here it is.

I'm quite certain about HPO output before AOM (which is "Power monitor PD" in D1002929) and ISS 1st loop monitors, but not that sure about "monitor PD"s in D1002164. E-travellers are incomplete (they don't say which one is installed where), so I'm just listing the nominal values for these "monitor PD"s.

Increased LLCV of CP3 from 18% to 20% because it took almost 9 min. to overfill today. 

MidY @ 1:40pm local

Opened CP3 bypass LLCV 1/2 turn with bypass exhaust valve open. Took 8:49 min. until vapor/liquid started to flow out the exhaust pipes. I waited several minutes before closing the bypass exhaust valve. Closed it a few times, pressure sounded high, so I opened it back up and then several seconds later liquid started to pour out. I did this three times, and then waited many minutes before finally leaving bypass exhaust valve closed.

Stefan, Evan

The attached plot shows the dark noise of the inner-loop ISS. It is "dark" in the sense that the NPRO is off, although there are still room lights on in the PSL.

PDA seems to have worse noise than PDB — a factor of 3 at 10 Hz. When the PDA/PDB inputs at the PSL rack are terminated, the noise performance is similar. So this excess seems to be somewhere between PDA and the PSL rack.

The traces are calibrated into equivalent RIN for the nominal ISS operating power.

Comparing with 26773 (for example), we see we are battling a noise that is more than a factor of 1000 worse than these dark noises.

HWSX peak counts bad, I stopped the code, powercycled the frame grabber and the camera, then restarted the code. Peak counts are back to normal (~940).

I restarted the HWS code on H1HWSMSR this morning. It had stopped following the Beckhoff failure last night.

• PSL is down, resulting in an opportunistic maintenance period today (and possibly through the weekend)
• Be aware of BRSes at both ends, Hugh is making stay clear signs for them
• Painters in the new LSB conference room

The attached 1 day trend plot shows the BRSY RX (tilt), wind speed, BRS Beam velocity, and the Y STS Seismometer motion.  Yesterday at the 1800 hours mark, the tilt and velocity rapid decrease is from when we forced the damping on.  Otherwise for the remainder of the plots, the BRS is running on its own.  The shape of the trends don't scale with the wind velocity as one might expect...

TITLE: 04/29 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Plagued by earthquakes, a bit of wind, and then laser trouble. Wasn't a great night tonight.

SEI note: I struggled to get ISI ITMX to stay in fully_isolated, even after the 0.03-0.1Hz seemed to be back to normal. I'm leaving it fully_isolated with the T240s in Low gain now, but it has fooled me before. Also is there a way for us to tell if one of the sensors is already in low gain? Should it be added to the DIAG to make sure all are in high gain?
LOG:

• 23:23 - Rick, Keita to PSL enclosure to make ISS measurement.
• 23:26 - Dale, guest into LVEA for a quick tour.
• 23:47 - Dale, Guest out.
• 00:10 - Evan H to LVEA to PSL rack.
• 00:14 - Evan out.
• 01:52 - Hit with a large earquake (6.9) off the coast of southern Mexico.
• 05:52 - Rick, Keita out for the night.

Keita, PeterK, Rick

Keita and I went out to the laser room to make some RIN measurements.

Short summary:

     Front end RIN seems normal both with the high power oscillator (HPO) running and with it off

     High Power Oscillator RIN much higher (>factor of 10).  Glitches (few cycles of 500 kHz) at abouyt 37 kHz on the hight power oscillator light, but not the front end light

     More tomorrow regarding this.

After shutting the laser (front end and HPO) down to reset the Long Range Actuator (via the reset button on the back of the control box), the HPO only came back up with about 1/4 of the expected power.  Troubleshooting and brainstorming on the phone with Peter, we tried increasing the diode currents by 1 A (left the laser in this condition).  This due to the low power and because the head 4 output dropoed from about 96% to about 91%, i.e. it came back about 5% lower after switching the laser off to reset the LRA and turning it back on.

HPO power (with internal shutter open, front end off) still only came up to about 50 W (expecting close to 200).

Peter suspects that some internal optic has been damaged.  We decided to shut the system completely down - lasers and chillers - and try a cold start in the morning.

I plan to talk with MattH and Olli Puncken at LLO first thing in the morning to see if they have any ideas or suggestions.

It's looking pretty likely at this point that we aren't going to have a high-power laser until we can go into the HPO to inspect the optics and assess the state of the HPO.  This would start next week on Tuesday at the earliest, when PeterK returns from vacation.

Assuming that the cold start in the morning is not successful, we will have to decide is we want to try to get a the 15 watts reflected from the HPO aligned and modematched to the PMC so we will at least have a low power beam to work with until next week.

I'm leaving the rX-BRS sensor correction at ETMY on over night, as far as I can tell at the moment it is doing very little, but if someone gets suspicious about ETMY motion feel free to turn it off in ISI-ETMY_ST1_SENSCOR_GND_RX_Match

Patrick, Matt, Kiwamu, Vern

We tried testing some code changes for the rotation stage. They didn't seem to work, so I reverted the change to the Laser Power library and went through the GUI to start afresh (copy new code from target directory, compile, run, etc.). Now everytime I do this I get a divide by zero error. (see attached).

Did someone change the code in PLC1 that introduced a divide by zero error, and not run it until we tried to now? Or did I somehow do this?

Chris, Carlos, Jonathan, Jim, Dave:

today we installed Chris' medm_time_machine software on the CDS workstations. This permits the user to ask how an MEDM screen looked like in the past, provided the channel data is available from the selected NDS server.

To open the feature, right-mouse inside an MEDM and select Execute (last item) and TimeMachine (last item on pull-out window). See figure 1.

As an example, H1 was locked at noon today and is currently unlocked due to an earthquake. Figure 2 is requesting the OMC DC-PDA filter module screen at noon (5 hours and 30 minutes ago at the time of asking). Figure 3 shows the current running MEDM on top, and the timewarped screen from 12:02 PDT today below it. The time strings in the upper right corner show the times. Channels which are not in the DAQ show up as white rectangles (for example strings, momentary buttons, redundent outputs). When the IFO was locked, the input was many thousands of counts.

One feature we added to the launcher today was to allow the user to set the precision of the playback data. In some screens a precision of 3 is good, for others lower precision makes the screen more readable.

Jonathan showed that by changing the NDSSERVER enviromnent setting and opening a kerberos ticket, this system is able to get data from the LDAS NDS2 server.

Things to note:

• This is a H1 only system, it does not handle H0 channels
• The default is to use the local CDS NDS server, which only has a lookback of 8 days. For more lookback, please use an NDS2 server

Made measurements of the oscillator power noise with a few photodiodes.

PowerNoise.png shows the free-running oscillator relative power noise
measured before the acousto-optic modulator.  This is more than 10 times
noisier than when the laser was installed in the H1 enclosure.  The
other trace in the plot is the out of loop of the relative power noise.
It is also about a factor of 10 higher than it should be.

    Whilst the power stabilisation was locked, I looked at the AC coupled
output of the photodiode and did not observe any oscillations.  The maximum
peak-to-peak variations were ~40 mVpp.