Tonight the COMM handoff is stable even without the OpLev damping on.  This is interesting because we have farily high microseism (above the 90% percentile all night) so it is possible for us to have a good night even with high microseism. 

I was able to make some measurements of the COMM noise with and without the oplev dampng on, and it seems that the OpLev damping helps.  I repeated the measurement twice, the second time the ground motion was larger.  The RMS down to 0.02 Hz was reduced from 300Hz to 144Hz the frist time, and from 600 Hz to 235Hz the second time.  In this calibration I have removed the cavity pole at 42 Hz.  ( This file is saved in sheila.dwyer/ALS/COMM/COMM_Noise_March27.xml)

I also tried reducing the gain of the ALS COMM loop.  Since 18dB gave us a 35 Hz ugf, I turned off the common comp and moved the gain down to -2dB, where we should ave a ugf of 350 Hz.  This reduced the gain at high frequencies, but there must be an instability around 10Hz in this configuration.  A screen shot is attached, and the data is saved as COM_Noise_March27_reduce_gain.xml

I have now turned off the OpLev damping so Fabrice can have some data to look at without damping in the morning.  I plan to leave the guardian locking the arm on IR over night. This should be usefull data for anyone from DetChar who wants to look at the arm locked on IR, or seismic. 

Valera called and asked for a measurement of the arm losses.  I used REFL_AIR, meaured 0 counts when the IMC was unlocked, 1.539 when the arm was locked with ALS off resonance, and 1.471 when the arm was locked on resonance.  The IR trans power was only 70% of the nominal, so the arm was not well aligned and this only gives us an upper limit on the losses, which is 159ppm, assuming the ITM transmission is 1.4%. 

A more accurate measurement shoud probably be done. 

I made an attemt to lock the ALS WFS YAW DOFs tonight.  I Inverted the sensing matrix measured in alog 10971, to make DOF1 the ETM and DOF 2 the ITM.

The WFS In matrix is now

0.065 0.042

0.045 -0.093

I could lock DOF 2 (the ITM Yaw) but could not increase the bandwidth above about 0.03 Hz.

DOF 2 seems to have an offset, when I align the cavity by hand the error signal is at around 38 counts, when I lock the loop it does supress the error signal, but this reduces the transmission of the cavity.   

Laser is on
Output power is 28.1 W (should be 30 W)
Watchdog is active
No warnings in PSL SYSSTAT.adl other than "VB program online" 

PMC
Locked for 3 days 7 hours (should be days/weeks)
Reflected power is 12.7% of transmitted power (should be 10% or less)

FSS
Reference cavity has been locked for 1 hour (should be days/weeks)
Trans PD threshold is .4 V (should be at least .9 V)

ISS
Diffracted power is 8.8% (should be around 10%)
Last saturation event was 22 hours ago (should be days/weeks)

Spent all day trying to go back to the blue trace in the attached (which is from yesterday afternoon), but we came back to red, which is basically the same as this morning except the frequencies of three finger structure.

We re-routed the cables twice, and neither of these attempts recoverd the Q of 1.75 and 1.4Hz thing. So much for my "bundling=bad Q for translational" theory which sounded good.

Unrubbing excersize reliably eliminated the elevated noise floor 0.8Hz-6Hz that probably came from rubbing, and made the Q of some modes good, but did not do it reliably for 1.75Hz and 1.4Hz.

At this point I have to say it's unlikely that we can reliably make it like the blue trace even if we go in the chamber tomorrow, so if nothing special comes up we need to button down. I asked Arnaud to run his TF. Tomorrow Jim should run his stuff again.

As for the three finger structure (0.6-0.8Hz), we need to live with it, it's not unique to this pilot unit (see the X and Y free swing spectra, due to low resolution it looks like two fingers for Y, but the point is that there are three resonances between 0.6 and 0.8Hz for X).

Took over for Jim ~ 9:35

09:40 Jim, Hugh to HAM 5
09:59 Jeff B. working on dust monitors near HAM 4,5
10:10 Andres working on SR3
10:29 - 12:30 Gerardo and David O. in H2 PSL enclosure working on OFI
12:00 Dave H. stopping work on TCS
13:00 Dave H. starting work on TCS
13:00 Corey, Keita and Jax running measurement on TMSY
13:05 Karen cleaning at end Y, not going into VEA
13:43 Kyle taking picture in end X VEA
13:28 Karen cleaning at mid Y, going to end Y VEA at 14:00
14:10 Gerardo and David O. in H2 PSL enclosure working on OFI
14:52 Karen back from end Y

Richard diagnosing dust monitor communications in LVEA

Just a couple of the things I struggled with today:

- Binary output chassis had to be replaced (see other alog)
- PR2 angular dither lines were left on by guardian (presumably on a crash)- they couple to length and use about 2/3 of the PRCL actuation range.
- In PRX and PRY the system still tends to ring up if it doesn't lock on the first trigger - we need some dead-time logic.
- In the end PRMI did lock up for about 10sec at a time. I did not have the energy to track down why it lost lock again.
- My initial alignment got me a build-up of about 50.

Aidan. Dave H. Thomas.

We went a couple of rounds with the plumbing on the TCSX table today. We fixed a couple of major and minor leaks and the plumbing itself looks fine. However, the laser housing itself is slowly leaking water. We will investigate further tomorrow but we'll likely have to swap out the laser for one of the remaining two units.

Cabling continues slowly. We're making headway but it is surprisingly time consuming.

Scott, Mark, Mitchell
The optical table, top and bottom, have been joined on the granite table. The bolts have been added and are in the process of being torqued. Optical covers 1-3 have been added, and torqued.

I installed the spare H1 RF preamplifier (S1203936) in ISC R1, and routed the COMM BBPD signal through it. 

I reconfigured a spare Acromag binary output chassis for replacing the broken unit.

The new unit is:
D1100251, S1203287

IP addresses:
10.40.12.21 (top left, as seen from the front)
10.40.12.22 (top right, as seen from the front)
10.40.12.23 (bottom left, as seen from the front)
10.40.12.24 (bottom right, as seen from the front)

Attached are print outs of the settings of the new box (S1203287) and the old box (S1203246).

The install of the lower ITMy ring heater was completed Tuesday evening. There was a small issue with fit for SN#203 glass former assembly, the nichrome was a tight fit into the macor (not nearly as bad as SN#210). The diameter of the glass and nichrome near the end was 0.276", some chipping of the macor was seen after the glass was seated. The temperature sensor (RTD) has loosened some, apparently from the re-install efforts, about the epoxy but is still showing the same resistance as before (109.5 ohm). 

Not sure what the deal is with my photos, but for some reason alog chooses to not let some of my photos upload to an entry.  Have used original names of images, and changed names of files.  Have tried from home and from work to no avail.  Will keep trying.  Attached is the error message I get afer I try uploading the file I select.

Entries made via MacBook Pro & with Firefox.

model restarts logged for Tue 25/Mar/2014
2014_03_25 11:11 h1broadcast0
2014_03_25 12:07 h1dc0
2014_03_25 12:09 h1broadcast0
2014_03_25 12:09 h1fw0
2014_03_25 12:09 h1fw1
2014_03_25 12:09 h1nds0
2014_03_25 12:09 h1nds1

no unexpected restarts reported.

When we went into the chamber we have found that the top cable rounting was done in such a way that

1. Cables were loose and rubbing with each other,
2. Cables were rubbing with the cable loops inside the top mass,
3. One cable was touching the inside wall of the top mass hole from which the cables come out.

These are all bad, and I spent some time last week to divide four cables into two groups to make sure that none of the above was happening, but the cables were re-routed yesterday evening and they were bundled together without paying attention to the above.

Two of the four cables that go through the TMS top mass are for picomotors and are much thicker than BOSEM cables (the core diameter is bigger). These are stiff cables, and it's very difficult to route them such that they don't touch anything, and this is especially true for the pilot unit (TMSY) where the cable clamping inside the top mass is totally different from production units. How this is done has a big effect.

Attached are free swing spectra of three different cable routing. It's convenient to remember that there is a three-finger structure between 0.67 and 0.82 Hz.

Freeswing, this morning, ie cable rubbing (green).

• Q of the 1.75Hz L resonance (top left) as well as 1.4Hz T resonance (bottom left) are really, really low.
• Q of 2.4 Hz and 2.5Hz peaks are low though it's hard to see without zooming in.
• The highest three-finger resonances (0.82Hz in this case) has a low Q.

Freeswing, after we made it the way we want it, no rubbing (blue).

We unbundled the cables, divided into three different routes (one route has two cables) and made sure that nothing is touching anything. This should be roughly the state of things from yesterday morning, except that the cables are divided into three instead of two (somehow it was very tough to do it right in just two routes today).

• Qs don't suck. Three finger Qs good. All in all highest Q for most resonances.
• But the resonances that used to suck, i.e. 1.4Hz and/or 1.75Hz split into multiple higher Q resonances.
• Frequency shift for the ring finger and the middle finger.

I believe that this is roughly the same state we were in during OAT days (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=2587)

Freeswing, after we bundled cables together and used zip ties so that the cables at least don't rub against each other (red).

This is the state we're in now, as I wanted to see if zip ties help after we tested the blue configuration.

• Q of the 1.75Hz and 1.4Hz suck.
• Q of 2.4 and 2.5Hz peaks are better than in the morning.
• Frequency shift for the ring finger and the middle finger.

So, all in all, I think we need to go back to blue state tomorrow. Note that free swinging spectra are not transfer functions. This is a good tool to detect rubbing/interference.

My estimate of N2 leak/outgassing for the Y1 module at LHO. The accumulation took place over 4.8 days.

Total pressure at the end according to the CC gauges was 5e-8 torr and the total RGA ion current was 2e-10 amps yielding 0.004 amps/torr(H2).

Ignoring the gauge factors I get an N2 leak/outgassing rate of 4e-9 tl/sec. There may also be a contribution from CO generated by the CC gauges.

Also, the RGA setup was coupled to the tube at an oring angle valve so

there are a number of small orings in close proximity to the RGA. Kyle did perform a mild bake on this setup. In addition, included in the accumulation

is the LN2 pump at YMID.

I would say we have no measureable air leak on Y1.

The RGA data is shown on a log plot for better visibilty - on a linear plot the curves appear straight.