(Fil, Mani, Daniel)

Adding the 10 MHz frequency reference to the RF synthesizer in the mechanical room turned out to be more involved than we planned. First, we noticed that some of the RF distribution cables were badly terminated and needed to be redone. We then found that no baluns were added—generating one big ground loop through the RF cabling.

This is the current setup:

• An RF patch panel from our stock has been added to the TCS rack in the mechanical room.
• The 10 MHz signal is routed to the mechanical room where the RF synthesizer uses it as an external reference. A balun has been added in the mechanical room.
• The RF synthesizer runs at 40.68 MHz and 13 dBm output on the N connector.
• The output of the RF synthesizer terminates in the TCS-R1 rack. A balun and an attenuator has been added at the R1 end. This signal is routed to the distribution amplifier.
• We used a free output of the distribution amplifier and routed the signal back to the CER. There we added yet another balun and routed the signal to the timing comparator/frequency counter. Channel 3 now reads back the TCS AOM frequency in Hz.

We noticed that thin coax cables were used to route the RF signals from R1 to R2. We should replace those with the proper thick coax which is used everywhere else in the distribution system.

We still need to route a DB25 cable from the RF distribution amplifier to the RF amp concentrator in the CER. This way we have both frequency and RF power readbacks available. The EtherCAT system was udated with the new monitor channels for the TCS RF distribution amp. This will make it straight forward to diagnose a problem with this RF synthesizer.

A new medm screen was made for the TCS RF distribution (see attached).

Kyle, Gerardo

Legacy pumps long past their nominal life expectancy -> Damaged knife edge of 2 1/2" O-ring isolation valve at HAM2 ion pump attempting to align flanges which were kept sprung misaligned by rigid non-perpendicular piping -> Had to remove damaged valve and replaced it with an elbow (will repair valve in house and keep as spare) -> Leak tested new joints -> Will now need to pump with pump carts for a few more days before energizing new ion pumps.  

Note: HAM1/HAM2 annulus volume was fully vented for a period of time -> no pressure change in Corner Station

Added 326 channels. Removed 57 channels.

The following 10 channels are unmonitored:

H1:GRD-TCS_ITMY_LOGLEVEL
H1:GRD-TCS_ITMY_MODE
H1:GRD-TCS_ITMY_NOMINAL_S
H1:GRD-TCS_ITMY_REQUEST
H1:GRD-TCS_ITMY_REQUEST_S
H1:GRD-TCS_ITMY_STATE_S
H1:GRD-TCS_ITMY_STATUS
H1:GRD-TCS_ITMY_TARGET_S
H1:SUS-SR2_LKIN_P_OSC_SW2R
H1:SUS-SR2_LKIN_Y_OSC_SW2R

Scott L. Ed P. Chris S.

52 meters of tube cleaned today from single door towards X-1-6 double doors. 
Continuous motioning of beam tube pressures during cleaning operations.  

I'm sitting in for Jeff who left early to go on vacation.

15:55 Kiwamu going to close the LASER shutter to HAM1 to do some testing on the rotation stage.

So what was supposed to be a simple favour for Aidan to turn the CO2y laser on turned out to be not so simple. Note: when I started this work I was unaware of the issues that Greg encountered last week (he has just put in an alog now for me alog 17302).

So at the moment the CO2y laser is still off.

Below is what observed/thought was the problem before hearing from Greg about the issues he saw previously (and is now alogging) , and also talking to Aidan about his recollections. Also will include what I think is going on for part of it and also recommendations.

Observation 1:

The rotation stage for CO2y is not working (I cant get it to do any rotation of any kind). I played with this before knowing that Greg had seen this last week also. I did not try playing with the CO2x. Based on past experience at LLO and LHO its going to be something with Beckhoff having to be reset (we really need to work out why these things just stop working). So until it is up and running I dont want to turn the laser on. And because I dont know how LHO like to proceed with doing procedures like this I took this no further. So what I need is for someone (maybe at start of next weeks maintenance period) to reset the HWP for me (probably just needs to be unplugged then replugged).   

Observation 2:

I went out to the mechanical room to check the status of the power supplies etc. I immediately saw two things that peaked my interest.
1. Only one of the Kepco power supplies is on and wired up?? and the one that was on was drawing no current (see pic Kepco power supply).  This I have seen before and indicates that one of the AOM drivers has faulted. But because things look to be hooked up weird (will discuss more later) looking on the tables I see that CO2y AOM driver is fine (indicated by the two green LEDs..see pic CO2yAOM driver), but the CO2x AOM driver has faulted (top LED red...see pic CO2xAOM driver). If you want to know what these fault lights mean please go to E1500133 and look at table 1 (someone should probably print this table out and stick it on or near the AOM driver for others for future reference). Now this has been seen before at LLO and the solution is to power cycle the power supply. However doing this will make the AOM start to work, and seeing as its not known when it faulted and what static diffraction setting the driver has been set to, once the reset occurs I could alter how much power is going to the interferometer (as CO2x laser looks like its being used). So again this is something should do during maintenance period (should note what power going to optic now and so when reset see how/if it changes and alter power accordingly). 

2. The CO2Y laser power supply seems to be drawing a funky amount of current. 2.5Amps actually (see pic TCSy power supply), even though the laser is off. Ive even turned the key on the controller off, so it shouldn't even be in standby mode where only draws 0.7Amps. Talking to Aidan he seems to think that maybe the AOM driver/AOM is drawing current from this supply (him telling me that made me recall we saw numbers like this back in the day when we were installing and the laser was off but we had the AOM driver on). He seemed to recall the AOM driver and CO2 laser are driven off the same supply still here at LHO (which was the original design), even though the plan was to change to having the CO2 laser and AOM driver driven off separate supplies (as has been implemented at LLO...the Kepco power supplies power the AOM drivers the other supplies power the CO2 laser only). But this doesnt seem to totally match with what Im seeing in the mechanical room. 

So looking at the wiring, here is what I think is the current setup at LHO. We are in some funky mid change between having one power supply do both laser and AOM driver and having separate supplies for all. In more detail......The two shelves showing the power supplies for TCS are shown in TCSracklowershelf and TCSrackuppershelf. How it should be as per the latest plan that I know of (and is at LLO) is that the on the lower shelf should hold the power supplies that power one table (ie say Y ) and for the upper shelf the power supplies for the other table (X) with seperate supplies for the lasers and the AOM drivers.  What seems to be the case is that:

       *on the lower shelf we have the Instek supply (I think thats the brand name....its the the one with the digital readout reading its drawing 2.5Amps that says TCSY on top of it) powering BOTH the CO2y laser and the CO2y AOM driver (I think this because the laser is OFF, as is the controller, but the AOM driver on the Y table has not faulted and is "running".The x table AOM driver has faulted and is not "running" and 2.5amps is an approximate number that the AOM driver could be drawing). 

       * The Kepco power supply on the lower shelf is wired up but not drawing any current at the moemnt and thus and looks to be powering the AOM driver for the X table (why... because the x table AOM driver has faulted its not drawing any current). It should be wired to be controlling the Y table if supply in the position at..or at the very least labeled clearly as to what it is powering. Mind you I could be wrong and its powering something else

      * The instek supply (the one showing the digital readout of 22.42 Amps) on the upper shelf is powering ONLY the CO2 x laser (its drawing this current as the laser is on). 

      *The Kepco power supply on this upper shelf is not even wired up and is thus off. 

What I suggest is at some stage when have some time (maybe during maintenance period next week), is to wire the system as per the new design (and as how is at LLO). One Kepco power supply is used for the AOM driver on one table and the other Kepco power supply be wired to the AOM driver on the other table. And then just have the other power supplies individually controlling the CO2 lasers. Should then also have the power supplies for one table on one shelf and the power supplies for the other table on the other shelf. 

Also when turn laser back on need to see if still only drawing half the current like Greg saw and if so investigate (probably cable connection is the problem like in the past). SO quite a few things would lile to do at next weeks maintenance period. 

10 days ago, Gabriele and Evan reported that there seemed to be a large offset in the IMC locking loop (alog 17131). In order to investigate this issue, I started from checking the health of the IOT2L optical table -- specifically we wanted to confirm that there is no stupid clipping or something crazy.

I did not find a clipping or anything crazy on the table.

(Health check of IOT2L)

I went to the IOT2L and checked the REFL path using a IR viewer and card, but I did not find an obvious clipping or any suspicious things. I found an iris which was letting the main beam go through but also scattering ghosts beams. The iris was in front of the BS which steers the beam to the REFL RFPD. I took out the iris and re-adjusted the razer blade beam dumps which have been meant to damp those ghosts. Also, I checked the centering of the beam on the REFL RFPD by steering the BS, but it was already centered.

(What happened to MC trans digital camera ?)

BTW, the IMC trans camera had been displaying nothing these days according to the hourly archives probably since some time in February. I realigned the camera as it seemed to be misaligned in YAW.  After adjusting the exposure, I realized that the beam shape completely changed from the image that I remembered -- see the attached pictures. The first attachment is the one from Feb-04-2015 and the second from today after my realignment. During the realignment process, I moved the camera position to see if this image is something bogus or real. I am concluding that this image is real. Something must have happened in the IMC trans path between early February and now. Sad.

Hugh and Krishna had found the BRS software had crashed pretty much on schedule, so Sheila and I went to the end-station to restart it. Pretty straightforward. Alogs 13817 and 15005 will get you everything you need to do it. The BRS is rung up right now because we went out to check the mass damper positions, but it should settle down in 30 minutes or so.

LVEA: Laser Hazard
Observation Bit: Commissioning   

07:00 Karen & Cris – Cleaning in the LVEA
08:22 Hugh – LVEA for HEPI maintenance work
08:36 Jodi – In the LVEA for 3IFO stuff
08:37 Christina – Forkliftng boxes from LSB to VPW
08:45 Jim B. – Starting work on the NTP server move
08:45 Matt – Turning on CO2-Y laser
08:50 Richard – Vacuum survey in the LVEA
08:51 HFD on site testing fire alarms
08:55 Kyle & Gerardo – Swapping out Ion pumps on HAM1 & HAM2
09:00 Peter, Jason & Ed – In the PSL for RefCav and FSS work
09:01 Corey – Working in the squeezer bay
09:34 Richard – Going to End-Y with HFD to test fire alarms
09:51 Hugh – Finished with HEPI in LVEA – Working on pump controller.
09:52 Jodi – Out of the LVEA
10:00 Praxair delivering N2 to Mid-X
10:03 Paradise Water on site
10:30 Filiberto – Working on TCS-X RF cabling
10:48 Richard – Back from End-Y
10:55 Kiwamu – Checking IOT2L for beam clipping
11:00 Doug – Looking for OpLev parts near HAM2
11:00 Peter, Jason, & Ed – Finished in the PSL 
11:05 Reset HEPI watchdog counters
11:38 Dave – Restarting new PEM corner station model & making cable changes in CER
11:42 Kyle & Gerardo – Out of the LVEA
11:50 Dave – DAQ restart
11:50 Kiwamu – Out of the LVEA
12:35 Karen – Going to End-Y
12:35 Cris – Going to End-X
12:43 HFD on site testing smoke alarms at End-X
13:10 Kyle & Gerardo – Leak checking at HAM1 & HAM2
13:51 Karen – Leaving End-Y
13:52 Filiberto – Connecting TSC RF cables
13:55 Kiwamu – Checking mirror pointing in IOT2L
14:22 Filiberto – Out of the LVEA
14:30 Kiwamu – Out of the LVEA
14:41 Jason – In LVEA getting parts from the OpLev cabinet
14:56 Jason - Out of the LVEA

We have turned off 3 LVEA heaters today as the winter season departs. It appears that temperatures in the LVEA are now back to nominal after an excursion of ~0.5F.

12 hours shown on the plot.

We'll continue to monitor the response.

I collected my performance data with the BSC in the right blend configuration this morning (sans modified blend filter, from my alog earlier today) and updated the HAM spectra from Friday, with slightly better color choices, I hope. See attached pdfs.

This is an issue from last week. While doing chiller maintenance last week I noticed that the power supply for the TCSx laser was running at only half power. I checked the cables and didn't find any obviously loose connections, but this has been an issue in the past. Less likely, but still possible is the RF driver failing. While on the table I noticed the rotation stage has once again gone glitchy and won't respond to requests or return to home. Most likely requires a Beckhoff reset. 

There is and has been a beam block in the laser path. For now the TCSy laser is disabled by the MEDM gate.

P. King, J. Oberling, E. Merilh

Summary

FSS RefCav TPD started drifting again, went in to re-align.  Check mirrors M23, M22, and M21, all found loose.  M23 and M21 pitch adjustments recovered RefCav TPD, M22 had no effect; all pitch adjustment screws locked.  FSS RefCav TPD left at 1.56V.  Adjusted M36 to optimize power incident on PMC_TRANS PD, now reading 23.03 W (up from 22.99 W).  Measured FSS TF, UGF measured at 195 kHz.

Details

The FSS RefCav TPD had begun to drift down again, so we went in and checked the remaining 3 mirrors in the FSS beam path: M21, M22, and M23.  We first checked M23 and found the pitch adjustment screw to be loose.  Turning this screw CW (pitching the mirror down) caused the RefCav TPD to change from 1.23V to 1.53V; the adjustment screw was locked.  M22 was also found unlocked, but did not effect the RefCav Trans; this adjustment screw was also locked.  The final mirror in the FSS path that we had not inspected before was M21, and lo-and-behold, the pitch adjustment screw was unlocked.  Turning this screw CW (pitching the mirror down) took the RefCav TPD from 1.53V to 1.56V; this adjustment screw was then locked.  We will continue to monitor the FSS RefCav TPD.

Since the transmission through M23 is responsible for the PMC_TRANS reading, we slightly tweaked M36 to optimize the reading of the PMC_TRANS PD.  Before the adjustment the PMC_TRANS was reading 22.99W, it is now reading 23.03W.

Finally, we took a TF of the full FSS loop, and measured the UGF to be ~195 kHz.  Peter has the full TF data and will add it as a comment to this post.

Checked and set all LVEA Supply Accumulators to 70psi; Return Accumulators set to 20-30psi.

Issues found at H(am)5R(eturn), H6S(upply), H5S, H4S, B(SC)3E(ast)S,B3W(est)S,B3WR,B2N(orth)S(unable to charge due to interference), B2NR, B1NS, B1SR, H3S, H1S, H1R, H2R.

Wow, maybe easier to list the ones that did not need some gas.  Most of the Supply units that needed charging where at 20psi or below. This should make a good improvement in pump pressure fluctuation coupling into to platform motion.  I expect next check should see a much shorter list.

Found that someone had decided to store unused 2" Angle Cable Tray Support Assemblies under BSC1.  Sliding these in, the Feet on the Assembly was just the right height to hit the valve knob and turn it.  Fortunately, the drain exit is capped and no leak occurred.  Please mind the caution tape and be aware of the pushing and pulling things in and around the low dark places where HEPI resides.

Noticed that the Vacuum Pipe, Instrument Air Piping and Conduit are all contacting the SR3 OpLev Transmitter Pier near its base.  This is just East of HAM4 on the North Side.

Sheila, Nutsinee

Attached below are the plots of PEM/ALS and PEM/ISI correlations. Using data from March 14 (we had high wind up to 45 MPH). The x-axes are wind speed in mph, the y-axes are either ALS-X(Y)_REFL_SCTRL_OUT_DQ (rms) or ISI-ETMY_ST1_FFB_BLRMS_(DOF)_(100M or 300M)_(300M or 1) (mean). The correlation (r) is calculated and printed in the parentheses. Since PEM-EX and ALS-Y seems to correlate the most (r=0.7783) I only plot the correlation between PEM-EX  and ISI-ETMY for the PEM/ISI correlation. PEM-EX and ISI-ETMY-RY (100-300 mHz) appears to have the highest correlation (r = 0.7469).

A Matlab script also attached.