Rana, Alberto, Pete

We have the DD handoff nominally working.  Sometimes, increasing the SRC gain at the end makes MICH get unstable.  This could be due to a non-diagonal term in the matrix, or possibly because the DRM locks in a funky mode sometimes. 

To get the DD handoff working, first we tuned demod phases in order to zero the offsets in the PD signals handed-off-to.  Based on transer function measurements, I set the PRC PD6_I element to 0.1, and set the PD8_I signal to 0, since it didn't seem to be contributing much.  We also commented out the MICH gain increase at the end of the DD_handoff script.

It could still be more stable, but it seems to work most of the time.

Tonight I centered the oplevs for ITMX/Y, SRM, PRM, BS.

After doing that I noticed that the BS drifted a little from where I had set it.

rob, alberto, rana, pete

we reset this computer, which was out of sync (16384 in the FE_SYNC field instead of 0)

I restarted ntpd on op440m to solve a "synchronization error" that we were having in DTT.  I also edited the config file (/etc/inet/ntp.conf) to remove the lines referring to rana as an ntp server; now only nodus is listed.

To do this:

log in as root

/usr/local/bin/ntpd -c /etc/inet/ntp.conf

alberto, pete

We worked on tuning the DD handoff tonight.  We checked the DD PD alignments and they looked fine.  First I tuned the 3 demod phases to minimize offsets.  Then I noticed that the post-handoff MICH xfer function needed an increase in gain to look like the pre-handoff xfer function (which has a UGF of about 25 Hz).  I increased the MICH PD9_Q gain from 2 to 7 in the input matrix.   But, the handoff to PRC still failed, so tomorrow we will try to find out why.

In the plot, ref0 is before MICH handoff, and ref1 is after MICH handoff.  There is also a PRC trace (before PRC handooff).

Some thoughts on what happened with the MOPA cooling. 

Some unknown thing happened to precipitate the initial needle valve jiggle, which unleashed a torrent of flow through the NPRO.  This flow was made possible by the fact that the cooling lines are labeled confusingly, and so flow was going backwards through the needle valve, which was thus powerless to restrict it.  The NPRO got extremely cold, and most of the chiller's cooling power was being used to unnecessarily cool the NPRO.  So, the PA was not getting cooled enough.  At this, point, reversing the flow probably would have solved everything.  Instead, we turned off the chiller and thus discovered the flaky start-motor capacitor. 

Now we have much more information, flow meters in the NPRO and main cooling lines, a brand-new, functioning needle valve, a better understanding of the chiller/MOPA settings necessary for operation, and the knowledge of what happens when you install a needle valve backwards.

I added op540m's display 0 (the northern-most monitor in the control room) to the MEDM screens webpage: https://nodus.ligo.caltech.edu:30889/medm/screenshot.html

Now we can see the StripTool displays that are usually parked on that screen.

The laser power seems to have become more stable after fixing the laser chiller. The power is lower than it used to be (MOPA amplitude 2.5 versus 2.7) but, as shown in the attchement, it became more steady.

The reboot appears to have worked.

c1susvme2 has been running just a bit late for about a week.  I rebooted it. 

The plot shows SRM_FE_SYNC, which is the number of times in the last second that c1susvme2 was late for the 16k cycle.   Similarly for ETMX.

I locked to PSL loops, then tweaked the alignment of the MC to get it to lock. 

I first steering MC1 until all the McWFS quads were saturated.  This got the MC locking in a 01 mode.  So I steered MC1 a little more till it was 00.  Then I steered MC2 to increase the power a little bit.  After that, I just enabled the MC autolocker.

I'm setting SLOWDC to about -5.

I had to edit FSSSlowServo because it had hard limits on SLOWDC at (-5 and 5).  It now goes from -10 to 10.

Steve, Rob and Alberto

Starting capacitor 216 miroFarad was installed on the compressor. Water lines were connected to the MOPA as corrected, so the flow meter readings are logical.

Now IN means flowing water in the direction of black arrow on the hose.

We struggled with the Neslab presetting:  temp, bauds rate  and other  unknowns  till Rob found the M6000 manual on Peter king's website.

Alberto realized that the chiller temp had to be reset to 20C on water chiller.

I put 1mg of Chloramin T into the water to restrict the growth of algae in the bath.

The NPRO heat sink  was around ~20C without flow meter wheel rotation  and the PA body ~25C by touch of a finger

I just opened up the needle valve a litle bit so the flow meter wheel would started rotating slowly.

That small glitch at the end of this 3 hrs plot shows this adjustment.

I drained the water and removed side covers from the Neslab RTE 140 refrigerated water cooler unit this morning. The hoses to the laser were disconnected.

This abled you to see the little window of refregerant  R404A was free of bubles, meaning: no recharge was needed.

The circulator bath was refilled with 7 liters of Arrowhead distilled water and the unit was turned on.

The water temp was kept 20.00+- .05C without any load. Finally the AC-repair man Paul showed up.

He measured the R404A level to be as specified: 23-24 PSI on the suction side and 310 PSI on the discharge side.

The unit was working fine. Paul found an intermittently functioning starting capacitor on the compressor  that was removed.

The 240 micro Farad 120VAC cap will arrive tomorrow

 The repair man thinks it's a bad start capacitor, which is 240uF at 120V.  Steve has ordered a new one which should be here tomorrow, and with luck we'll have lasing by tomorrow afternoon.

steve, alberto, rob

After some futzing around with the chiller, we have come to the tentative conclusion that the refrigeration unit is not working.  Steve called facilities to try to get them to recharge the refrigerant (R-404a) tomorrow, and we're also calling around for a spare chiller somewhere in the project (without luck so far).

 The chiller appears to be broken.  We currently have it on, with both the SENSOR and RS-232 unplugged.  It's running, circulating water, and the COOL led is illuminated.  But the temperature is not going down.  The exhaust out the back is not particularly warm.  We think this means the refrigeration unit has broken, or the chiller computer is not communicating with the refrigerator/heat exchanger.  Regardless, we may need a new chiller and a new laser.

 Rob, Alberto

The chiller HT alarm started blinking, as the water temperature had reached 40 degrees C, and was still rising.  We turned off the MOPA and the chiller.  Maybe we need to open the needle valve a bit more?  Or maybe the flow needs to be reversed?  The labels on the MOPA are backwards?

steve, rob, alberto

Steve installed two rotary flow meters into the MOPA chiller system--one at the chiller flow output and one in the NPRO cooling line.  After some hijinks, we discovered that the long, insulated chiller lines have the same labels at each end.  This means that if you match up the labels at the chiller end, at the MOPA end you need switch labels: out goes to in and vice-versa.  This means that, indubitably, we have at some point had the flow going backwards through the MOPA, though I'm not sure if that would make much of a difference. 

Steve also installed a new needle valve in the NPRO cooling line, which works as expected as confirmed by the flow meter. 

We also re-discovered that the 40m procedures manual contains an error.  To turn on the chiller in the MOPA start-up process, you have to press ON, then RS-232, then ENTER.  The proc man says ON, RS-232, RUN/STOP.

The laser power is at 1.5W and climbing.

Guralp Vert1b and Guralp EW1b are plugged back in to PEM ADCU #10 and #12 respectively. Guralp NS1b remains plugged in. So,  PEM-SEIS_MC1_X,Y,Z should now corrsp to seismometer as before.

I just restarted the elog.  It was crashed for unknown reasons.  The restarting instructions are in the wiki.

we did a hard reboot of c1susvme1, c1susvme2, c1sosvme, and c1susaux.  We are hoping this will fix some of the weird suspension issues we've been having (MC3 side coil, ITMX alignment).

The MOPA is taking the long weekend off.

Steve went out to wipe off the condensation inside the MOPA and found beads of water inside the NPRO box, perilously close to the PCB board.  He then measured the water temperature at the chiller head, which is 6C.  We decided to "reboot" the MOPA/chiller combo, on the off chance that would get things synced up.  Upon turning off the MOPA, the neslab chiller display immediately started displaying the correct temperature--about 6C.  The 22C number must come from the MOPA controller.  We thus tentatively narrowed down the possible space of problems to: broken MOPA controller and/or clog in the cooling line going to the power amplifier.  We decided to leave the MOPA off for the weekend, and start plumbing on Tuesday.  It is of course possible that the controller is the problem, but we think leaving the laser off over the weekend is the best course of action.

Looks like something went nuts in late April.  We have yet to try a hard reboot.

I edited the configure scripts (those called from the C1IFO_CONFIGURE screen) for restore XARM and YARM.  These used to misalign the ITM of the unused arm, which is totally unnecessary here, as we have both POX and POY.  They also used to turn off the drive to the unused ETM.  I've commented out these lines, so now running the two restores in series will leave a state where both arms can be locked.  This also means that the ITMs will never be deliberately mis-aligned by the restore scripts.

Yoichi's final words on what do next with the interferometer (as of 5 PM on May 21, 2009):

1. Measure laser noise couplings in spring and anti-spring configurations.
2. Dewhitening filter turn on for the ETMs.
3. Noisebudget - import from the sites.
4. Stabilize CM handoff.

My personal sub-comments to these bullets:

1. For the laser noise I'm not sure that we will be able to understand these if the couplings are mainly from junk light due to accidental HOM resonances.
2. WE should look into putting a static passive stage of filtering into the ETMs if warranted by the NB.
3. Because of the sad track record with this, I will start us off this time by importing and modifying the H1/L1 versions.
4. I guess we can do this by just acquiring on MC2 with the huge CARM offset. It works for the single arm so it should work for offset CARM.

 I also made xfer fctns of the 4 piston coils on ETMY and ETMX with OL_PIT.  (I looked at all 4 even though the attached plot only shows three.)  So it looks ike the coils are OK.

I've disabled the alarm for PEM_count_half, using the mask in the 40m.alhConfig file.  We can't do anything about it, and it's just annoying.

Rana suggested using OSEM sensing voltages as guide lines to look seismic activity.

As you see todays drilling and tumping activity was nothing compared to the EQ of mag 5 and 4

Optic level servos are turned back on.

What Steve means is that there is some drilling going on in the CES shop to accomodate the new water flume group. We want to

make sure that the mirrors don't move enough to break the magnets. On the dataviewer we should look to make sure that the

sensor channels stay between 0-2 V.     -Rana

 Wilcoxon 731A seismic accelerometers and Guralp CMG-40T-old seismometer at magnitude 5 and 4 erthquakes

All oplevs servos turned off to protect our suspentions from vibration due to drilling and pounding in CES high bay area.

This activity will be done from 10 am till 3 pm today.

Meanwhile our IFO-air conditions are turned off for maintenance.

Their performance of 6 months is shown on plot.

Recently the watch script was having difficulty grabbing a lock for more than a few seconds.  Rob discovered that the violin notch filters which were activated in the script were causing the instability.  We're not sure why yet.  The script seems significantly more stable with that step commented out.

I found some neat signal analysis software for my mac (http://www.faberacoustical.com/products/), and took a spectrum of the ambient noise coming from the cryopump.  The two main noise peaks from that bad boy were nowhere near 3.7 kHz.

  Earthquake mag 4.0 at Lennox, Ca     trips MC2 watchdogs       http://quake.usgs.gov/recenteqs/Quakes/ci10411545.html

See 40m accelerometers as they see it.

Even more plots for the Wiener filtering!

We have a set of spectrograms, which show (in color) the amplitude spectrum, at various times during a one month stretch of time, during S5. Each vertical data-'stripe' is 10min long.

We also have a set of band-limited plots, which take the spectra at each time, and integrate under it, for different frequency bands.

Each set of plots has the following 3 plots:  The raw DARM spectrum, a ratio of residual/raw, and the residuals, normalized to the first one (on which the wiener filter was trained).

The residuals are the DARM spectrum, after subtracting the Wiener-filtered seismometer witness data.

From the ratio plots, it looks like the wiener filter is pretty much equally effective at the time on which the filter was trained, as one month later.  Static filters may be okey-dokey for a long period of time with for the seismic stuff.

CYAN -  cryo ON
BLACK - cryo OFF
BLUE -  no crappy lens + mount