For SDF tables which have many items and therefore are being paged, we found that selecting the "Sort on Substring" option crashes the EPICS process with the segfault error 4. This was the cause of the restarts of h1susetmy, h1susitmy, h1susitmx, h1isiham6 and h1odcmaster this afternoon. Some of these restarts were to verify the error. Initial testing on the DTS against RCG-trunk is not showing the error. FRS ticket 3330 has been opened.

Plots of the PSL chiller 60 day trends. Most look normal, except the crystal chiller conductivity. It is getting close to the upper limit. Will need to monitor this and replace the Di filter cartridge in the future.   

I can only assume that I spaced this out when I pulled the previous STS2-B out to go to the EndX last Tuesday and replaced it with the previous STS2-A unit.  If anyone else actually uncovered the igloo, please let me know so I don't have to alert my doctor.  So, the ITMY STS2-B unit which is not used for any SEI function, was not ideally thermally insolated from mid-morning 7 July until late morning 14 July.

All fifty (50) Accumulators were checked for charge today.  No Accumulator needed charging.  Only three accumulators showed a decrease in pressure since the last charge check on 21 April, see T1500280.  These were small decreases (few psi) and likely reflect loss from gauge pulloff (does the uncertainy principle apply?)  The acceptable range of 60-93% of operating pressure is quite broad and the lowest reading today was at 80%.

Given these results, and, the reservoir-fluid-level-indication of Accumulator charge which can be checked with the system pumping, this invasive, must have system off accumulator pressure check could be done just quarterly.  As long as the weekly check of reservoir fluid levels show no decrease, the accumulators can be assumed to be adaquately charged.  If a weekly check of the reservoir fluid indicates a volume loss, then the accumulators could be checked.

Added 1962 channels. Removed 192 channels.

h1susetmy epics process died after running for a few hours, here is the dmesg output

[12094.731546] h1susetmyepics[17317]: segfault at 5a5c8c0 ip 00007f0fb70f2814 sp 00007fff81a06540 error 4 in libc-2.10.1.so[7f0fb7077000+14c000]

[12095.732645] h1susetmyepics used greatest stack depth: 2984 bytes left

It should not be on during data taking.

CO2X laser RTD sensor alarm (H1:TCS-ITMX_CO2_INTRLK_RTD_OR_IR_ALRM) tripped at 14 Jul 15 17:15:00 UTC this morning (10:15am), shutting off the CO2X laser.  Folks were pulling cables near HAM4 this morning, which is probably why it tripped.  CO2X laser was restarted at 19:30:00 UTC, and is now running normally again.

After bringing the IMC down this morning, we had trouble getting the IMC back up. The alignment was bad enough after recovering the seismic and sus that the wfs would walk out of alignment. Keita recovered the alignment by ramping the WFS gain down (on IMC_WFS_MASTER screen (under the IOO dropdown), lower left, it's nominally .1) and moving MC1 and MC2 to maximize the power on MC2_TRANS_SUM and minimize IMC_REFL_DC_OUT, while watching them in dataviewer. He then tweaked MC2 to center MC2_TRANS P and Y to near 0 (~.001) on the PD (on the IMC_CUST_OVERVIEW, top right, on the little pd graphic right of MC2). The gain on the WFS was then ramped up to some small number (I think ~.004? maybe .04) and the IMC watched to make sure it didn't go unstable. When it looked stable, the gain on the WFS was ramped back up to .1.

We wasted a bunch of time trying to retrieve earlier alignments, clearing wfs histories and moving the PZT (a strange land where pitch is yaw and yaw is pitch), before Keita decided to just do the realignment by hand.

J. Oberling, R. Savage, J. Bartlett

Summary

We went into the PSL to tweak the beam alignment into the FSS RefCav and PMC.  The FSS TPD was left at 1.67 V with a RefCav visibility of 85% and we found that the RFPD DC monitor on the FSS MEDM screen is not reading accurately; will have to fix this.  We still are not sure what is causing the drift.  Due to time constraints we did not touch the PMC, currently planning on doing that during the next maintenance period.

Details

Here is the FSS as we found it upon entering the PSL enclosure:

• TPD: 0.556 V
• RFPD DC: 0.015 V
• Power incident on L10 (meas with small thermal head): 65 mW
• Power incident on lower periscope mirror: 30 mW

We performed the following steps to realign the beam into the RefCav:

• We first adjusted the beam on the Reflection PD (RPD) to better center it, using the RFPD DC output on the FSS MEDM screen as a guide
  • Raising beam on rfpd by 1/4 turn of mirror in front of rfpd increased dc level 60-70 mv
• Then we adjusted pitch on the bottom periscope mirror.
  • Backing off vertical got the TPD up to 0.85 V
• Using the upper and lower periscope mirrors, we walked the beam up the RefCav input.
  • TPD was up to 1.50 V with only this vertical walk
• Maxed the TPD using a horizontal tweak on the top mirror, then a small walk to the west using both periscope mirrors
  • TPD up to 1.575 after horizontal walk
• At this point the RF PD was reading 0.133mV
• We touched up RFPD alignment
  • RFPD to 0.130mV
• Final TPD reading of 1.581V

At this point we wanted to measure the visibility of the cavity.  We plugged a multimeter into the DC port of the RPD and noticed that the reading on the multimeter was different from the reading on the RFPD DC monitor on the FSS MEDM screen.  Rick then used the multimeter to center the beam on the RPD; this was done while the loop was locked.  There was no change in the TPD voltage.  We then measured the RefCav visibility:

• RPD w/ FSS Locked: 38 mV
• RPD w/ FSS Unlocked: 255 mV
• RefCav visibility: 85%

Finally, we set the UGF of the FSS loop.  To maintain the UGF at 500 kHz we set the FSS common gain at 26dB.  This gave a UGF of 500 kHz and a phase margin of 59°

After all was said and done the RefCav TPD had a final reading of 1.67 V.  In the interest of time, we then left the PSL without adjusting the beam alignment into the PMC so Robert could begin his work with the IO periscope.  We plan on returning to the PMC alignment next maintenance period.

Kyle, Gerardo 

0850 - 0900 hrs. local -> In and out of Y-end 

Kyle, Gerardo 

Connected LD to exhaust of Y-mid turbo and sprayed helium on turbo fittings -> Found that this turbo has a "Leak valve" a.k.a. a solenoid vent valve which is either not connected or absent altogether on the site's other Main Turbo Pumps (MTPs) -> The turbo had been left levitated but not spinning since John W. and Gerardo's earlier investigation -> As such, this vent valve would be open -> Found that the clamp for the blank on this valve was loose -> Tightened -> With the turbo levitated but stopped, the QDP80 running but valved-out, safety valve and turbo bypass valve opened we sprayed the turbo's CFF and NW fittings with no obvious "smoking gun" -> It is likely that tightening the blank on the vent valve may have been the leak on the turbo side of the 10" gate valve 

For our next session we will vent the turbo volume and remove and replace the vent valve with a blank followed be a leak testing of the CFF joints on the Y-mid volume

Also, set IP9 to Fixed 7000V -> This leaves only the X-mid still in Step Mode (currently 5000V)

These are the ones added last week that are not used as interlocks for the high voltage. I updated the parameter settings to read out in Torr and wrote them to nonvolatile memory. This was an online change that did not require a restart.

Was not running when I came in. Not yet sure why or when it stopped.

Sheila, Jenne, Matt, Stefan, Evan

List of things done today:

• EY L2 now has a rolloff filter (FM7+FM8 in the L2L drivealign) to remove the unwanted L2/L3 crossovers around the violin resonances.
• We switched the BS M2 coil drivers to the low-noise state.
• We spent some time investigating in-vac REFL9 as a CARM sensor:
  • We drove a line into MCL at 48 Hz and then tuned the analog delay line to minimize the apperance of the line in REFL9Q. We found that the best extinction we could get was REFL9Q/REFl9I ≈ 1/5, which seems abysmal.
  • We switched the CARM sensor to REFL9I (settings attached for 23 W operation), but the high frequency DARM noise is worse than with REFLAIR9I.
• We were able to switch control of the common dofs of the test mass ASC into the hard/soft actuation basis (not measured, but calculated from the cavity geometry).
  • This new acutation scheme works fine when engaging the ASC and when powering up (at least to 10 W).
  • The gains of cHard pitch and yaw were adjusted (to -10 and -20 ct/ct, respectively) so that the loops have bandwidths of something like 300­–500 mHz (measured by step response). A bandwidth of 500 mHz will allow us to set reasonable bandwidths for the cSoft loops (perhaps 100 mHz or so?) while still maintaining the appropriate gain hierarchy between the loops. (According to simulation, the hard mode must be suppressed before the transmission QPDs become good error signals for the soft mode.)
• We also looked at the DARM spectrum as a function of DARM offset. Evidently, at lower offsets, the low end of the spectrum improves while the high end gets worse.

[Matt, Jenne, Evan, Sheila]

There is an enormous peak in the DARM spectrum at 4735 Hz.  Shown in the DTT printout below is the IOP channel for the OMC DC PD (H1:IOP-LSC0_MADC0_TP_CH12), from 1 kHz to 25 kHz, and this 4.7 kHz peak is dominating by about 2 orders of magnitude.  

We wonder if this is perhaps an acoustic internal mode of one of the test masses, although we are having trouble finding a listing of such modes.  

Does anyone know where we can find a listing of test mass acoustic modes?  Or, alternatively, does anyone have any thoughts on what this mode might be?