Jeff and Thomas went in the BSC3 chamber to do some B&K measurements on the arm cavity baffle.

I ran a quick transfer function on Stage1 after that to see if everything was still okay, since we had some weird interation between the ISI and the baffle yesterday (see aLOG #8632). Well, it is not okay...  (see plot attached)

Some huge overdamping/frequency drifting suddenly appeared. We don't know what could cause that yet (eddy current? cable rubbing?).

To keep going with this unit, we really need to understand what's happening. We'll continue the investigation tomorrow.

The TMSX crew are done for the day and have left the suspension in a hopefully good state, so I'm starting Matlab TFs at 16:45.

- Filiberto to LVEA, BSC03/BG area, check on electronics related to ITMX osems troubles.
- FC party at HAM02.
- Norna to the LVEA, HAM02 area, to join FC party.
- Port-a-Potty vendor, to all site, weekly service call.
- Apollo at Y-End, VEA area, removal of spool piece.
- Kyle at Y-End, VEA area, opening GV17 post spool removal.
- Jeff and Andres to X-end Station, VEA area, TMS related work.
- Cheryl to X-End, retrieve camera equipment.
- Cheryl, to LVEA, HAM02 survey for IO.
- Jeff K, to LVEA, HAM02 baffle, to do B&K testing.

On October 31, Jim & I got all the WBSC9 (ETMX) HEPI Actuators connected.  This included a couple swaps of the Parker Valve on V3.  The process would have you shut the supply to the system to depressure the valve to minimize fluid loss/spillage.  Today while at EndX troubleshooting ISI electronics, the HEPI pump station was checked as it hadn't been for several weeks and fluid was found in the pressure relief drain hose suggesting the pressure had exceeded the ~125psi relief point on the mechanical relief valve.

The trends were checked and sure enough the pressure spiked on the 31st showing a max of 105psi.  Who knows how much higher it actually went relative to these epics data.  Regardless, I suspect this spike in pressure opened the relief valve briefly and then closed when it dropped.  The pump station pressure was controlled by servo and the controller reduced the motor speed accordingly.

Couple things  1) At the end stations there is only one chamber on the system so when the supply valve is shut, the system is dead headed.  Unlike the corner station which has isolating supply & return valves on every chamber, the end station will likely see this spike if the servo is on and the supply valve is closed too quickly.  Not sure if you can close the valve slowly enough to prevent this spike.  I suspect you might be able to do so having the motor slow to a crawl and keep the dead head pressure at the set point and not spike it too badly.  At the end stations, the better solution might be to reduce the set point to very low value and then slowly close the valve.  A good alternative may be to put the system into primary recirc mode; that is open the system by-pass at the reservoir.  Then the chamber valve could be shut with only minor concern about valve actuation speed and pressure spikes.

2) Now that the pressure relief drain hose has fluid in it, it should be drained to ensure it doesn't thicken/dry out in the line blocking future fluid flow.  Not sure if this is a probability but it certainly is possible.  Our experience with the fluid is that it does become more viscous once isolated in small quantities, i.e., drops or puddles.  Also, this fluid is no longer in the system and the reservoir is therefore closer to tripping for low level--something we'd like to avoid.

So, although long on my to-do list, alarms on the pressure channels should be installed with low priority guidance to investigate the pressure relief line and drain as needed.  At the same time, the fluid levels should be checked with respect to the level trip point and topped up as required.

(Alexa, Rich)

We tested the two beam diverters in HAM 6. We found that BDIV-C in beckhoff is connected to BDIV2 in the OMC REFL AIR path, and BDIV-D is connected to BDIV1 in the AS AIR path (this follows schematics). The readback and controls are all okay; however BDIV1 failed everytime we tried to open it. BDIV2 also had difficulty opening, but did not always fail. It seems that the beam diverters get stuck as they move. 

Also, if the beam diverters remain as currently placed on the table, we will need to switch the open/close functionality in software. I will wait until final alignment before implementing this. 

End X picos are mislabeled in the medm screen. I will fix this later.

The pico labeled as M3 (green) (motor 1) is the last one in the IR path (M14)

one labeled as M6 9 green and IR (motor 2) was dichroic (M4)

labeled as M4(IR) motor 3 was steering mirror right in front of periscope (M6)

one labeld as M14 (IR)  motor 4 was first steering mirror for green path (M3)

Keita, Stefan, Sheila

The last item currently we are missing for HAM6 is a QPD sled (see 8633) from the ISC point of view. But the preparation of the sled is not going well.

ModeMaster is not functioning:

Yesterday, I was going to start preparing the sled which requires the use of a ModeMaster for the precision lens adjustment. However it seems that the germanium detector of our ModeMaster is not functioning for some reason. It worked fine with a different silicon detector, but didn't work with the germanium one. I looked at the output from the detectors with an oscilloscope. The silicone showed a square-looking, 20 Hz-modulated output and the amplitude seems depending on the amount of laser power, which makes sense to me. However, once I switched the detector to the germanium one, it showed a similar square-looking wave, but the amplitude didn't depend on the laser power. Moreover, the signal seems just railing -- it swung from -5 to 13 V in every square wave. I incline to conclude that the germanium detector became broken.

Trying to get a replacement:

I already sent an email to Adam and Valera in Livingston to see if they can lend us their ModeMaster. At the same time, I will get some technical support from the company and hopefully get some replacements.

When testing the demod concentrator readbacks at HAM6 we found more DB37 cables with unconnected pin 19. Unfortunately, this leavs the common mode potential undefined.

Spent all day moving top blade back and forth.

There are three problems with this approach, i.e.

1. Each time we move the blade, we need to REALLY check any mechanical interference, and we repeatedly thought that nothing was touching only to find later that something was touching.
2. There's no real feedback as to how much we're moving (though Jeff was getting better).
3. When loosening the blade PIT changes, and when tightening there's a large-ish YAW change while PIT doesn't completely go back (again Jeff was getting better to control this using smaller steps).

Tomorrow we might move the cage using pushers to address all three problems at once.

On a brighter note there were victories also, i.e.

1. Beam diverter moves. And we even found that "open" and "closed" logic are reversed. Success!
2. Picomotor GUI was fixed though we didn't test the picomotors. Success!

J. Kissel
[[This is a more detailed version of LHO aLOG 8590, for completeness]]

In-air, chamber-side testing of the H1 SUS OMC (an OMCS) has been successful, and the suspension is approved for install. The only things of note:
(1) The middle mode of Pitch to Pitch transfer function, modeled to be at 1.9 [Hz], has stiffened up to higher frequency, revealing that cabling is stiffening up the SUS, as has already been seen at LLO (see LLO aLOG 9570). I've informed Koji and Jeff Lewis, and they will work on softening up the connections as best they can. Like the reaction chain on the QUADs, it doesn't really matter, because the high-frequency behavior remains equally isolated (where it counts), but we should on a target-of-opportunity, best-effort basis try to get the cabling loose enough to get to at least Livingston's level, if not back to the what the model expects (which, is cable-free). The requirement is that one is conscious of it, and spend some time on it, but on the order of 30 minutes, not 30 hours.
(2) The damping loops (documented in LHO aLOG 8571) are in no-way commissioned using any quantitative metric. Thus, what little difference is seen between damped and undamped spectra is sad, but not unexpected. We'll commission these better later, I promise.
(3) It really is impressive to see the amount of isolation one gets between chamberside testing and on an in-vacuum, damped only isolation platform. Way to go team SEI/SUS!

-----------
Details

Undamped Transfer Function data set: 2013-11-15_1830
Damped Transfer Functions data set: 2013-11-15_2153
Damped/Undamped Spectra: 2013-11-15_2200

TF Comparions:
L1 OMC M1 (2013−06−16_1200): Phase 2b, chamberside, in air, damping OFF
L1 OMC M1 (2013−06−19_1055733803): Phase 2b, chamberside, in air, damping ON
L1 OMC M1 (2013−08−28_1030): Phase 3b, in-vacuum, damping off, ISI damping only
H1 OMC M1 (2013−11−15_1830): Phase 2b, chamberside, in air, damping OFF
H1 OMC M1 (2013−11−15_2153): Phase 2b, chamberside, in air, damping ON

Spectra Comparisons:
L1SUSOMC 2013−06−17_0900: Phase 2b, chamberside, in air
L1SUSOMC 2013−10−23_1130: Phase 3b, in-vacuum, ISI damping only
H1SUSOMC 2013−11−15_2200: Phase 2b, chamberside, in air

All data. scripts, and plots have been committed to the SusSVN as of this entry.

The controls user environment has been modified by including setup scripts from /ligo/apps/linux-x86_64/guardian/etc and /ligo/apps/linux-x86_64/cdsutils.

Jim started a measurement for the night. Should be done by tomorrow morning.

*** HPI ***

Unlocked

*** ISI ***

Undamped

*** SUS ***

Damped

The osem signals of ITMX L1 are zeros right now. We should take a look at it tomorrow.

[Jim, Sebastien]

As we discussed during the SEI meeting today, we noticed 3 main issues on the BSC-ISI ITMX transfer functions taken by Hugo and Jim last week (https://dcc.ligo.org/DocDB/0070/E1100848/007/ITMX_TF__2013_11_19-2.pdf).

Extra resonances around 2Hz (fixed)

Two extra resonances at 2.05Hz and 2.275Hz appeared on the ST1 main transfer functions (CPSs, L4Cs and T240s). Since it shows up only on Stage1, it must be coming from the arm cavity baffle installed on Stage 0. We locked/unlocked the baffle to see if it makes any difference.

The measurement showed in the first plot were taken using DTT and a white noise excitation.

As you can see, after locking the baffle the first time, the issue seems to be gone! Our theory is that the eddy current damping wasn't working properly on the baffle. By locking and unlocking it, we changed it in some way to make it better. To comfirm that theory, the next step would be to remove the copper block from the baflle and see what happens on the ISI.

Low gain on L4C-H2 (fixed)

L4C-H2 gain was down by a factor of 2. We first though of a bad connection somewhere, preventing to have a real differential signal. After we "played around"  (swaping cables, checking cables and screws), it seems to fix itself (!! see plot attached). The blue curve is the ASD before the "fix", the purple one is after.

We don't really know what action we did to make it happened, and how to reproduce the situation.

ST1-CPS-H1 high amplitude at high frequencies (not fixed yet)

The ST1-CPS-H1 main transfer function shows an unusual high amplitude level above 25Hz. We first though that something was loose, but Jim inspected everything and couldn't find anything wrong. We'll investigate more tomorrow (CPS grounding issue???)

This quick and confusing analysis is a first result and need more data to be confirmed. A full set of transfer functions will be take tonight.

This afternoon I moved the CDS wireless AP from the top of the 'test stand' racks to it's permanent location on the tray exiting the CER at the corner of the south and east bays.  Signal coverage in the LVEA is largely unchanged, but now better than it was in the H1 PSL area/CER.