Today, we were able to take the charge measurements on both ETMX and ETMY SUSes.  Someone musta started jumping around part way through the ETMX ones because the error bar is much larger on today's data points and a few of the points were omitted altogether because they just didn't have any coherence.  Recall the sign was flipped last week so we've had 1 week of "charge turnover" which is starting to show in the attached long trends.

Krishna & Hugh

The attached 30 day plot shows the DRIFTMON Channel.  This indicates the DC position of the Hanging Beam in the BRS assembly.  The data are the relected position of the Diffraction Lines on the linear CCD array.  The range of operation is +-16000 and it drifted bad over the weekend.  Krishna arrived Tuesday AM and completed adjustment around noon.  The adjustment is made by shifting (yawing) an 8gram bar, maybe a couple inches long, attached at one end.  This is in vacuum so I don't have any photos.  In this case, the adjustment to put the drift back at a good position for the continued drift expected, was at most a few 10s of um at the end of the bar.  It took many tries and lots of patience.

It looks like Krishna got it into a pretty good place and we hope to tolerate the drift for a few weeks before this is again necessary.  It is suttle but it looks like the drift is abating but albeit quite slowly.

J. Kissel, R. Abbott

I'd had a curiousity conversation with the great Rich Abbott at the LVC meeting, for which I just found my notes. The line of inquiry was on the limitations of the wave front sensors (WFS). I was curious what it would take to improve the angular sensitivity -- which is limited by shot noise above a few Hz. (Improving the sensitivity would in turn allow us to increase the angular control bandwidth without polluting the DARM sensitivity).

The numbers:
The WFS are shot-noise limited as long as each quadrant (of which there are four, of course) receives ~3-4 [mA] of photo-current. 
The WFS quadrants' electronics saturate at 15 [mA].

For reference, the LSC PDs are shot noise limited above 1-2 [mA]. It's less because the diode is smaller, so the PD's capacitance is lower.

Added Beam Rotation Sensor usage info on the BSC ISI Overview.  The signals that produce the Active indication are necessary but not sufficient.  There are a number of elements that must be inplace (turned on) for implementing the BRS correction.  But the correction will be inabled/disabled typically via the MATCH gain.  This will eventually be controlled by the guardian.

For operators now, if someone is going to the End Stations and will be anywhere near the BRS, it should be disabled, for now by notifying SEI and otherwise zeroing the gain on the Beam-line Match bank, see 1st attached shot: If the BRS box on the ISI OVERVIEW indicates Active, open the ST1 SENSCOR medm and then the translational MATCH medm and zero the Beam-line gain: X for EndX etc.

For the Seismometer Mass Centering, the need for which is identified by a scheduled FAMIS task result, (see 26426 & 26418,) this task must be preformed with the Seismometer out of the control loop.  Bring up the BIO medm accessable from the ISI OVERVIEW, see the 2nd attachment.

For the T240s, an individual BSC SEI Manager is taken to DAMPED.  When in the DAMPED state, the T240 needing centering's mass is pushed by pressing the numbered (corner) button in the AutoZ area of the T240 Outputs group.  The AutoZ widget should show engaged (going green,) press again to disengage after at least 1 second.  The U V W mass positions can be monitored for efficacy of the process in the T240 Inputs group; these numbers should get smaller.

For the floor seismometers (STSs at the moment) doing the CPS sensor correction, the process is more involved as the seismometer is correcting all chambers.  All HAM chamber's Sensor Correction MATCH filter gains are zero'd.  For BSCs, the Z correction is applied to HEPI while X & Y go to the ISI, so all those must also be zero'd.  There is a script for this built by TJ, alog 25936, repeated here:

thomas.shaffer@opsws10:/opt/rtcds/userapps/release/isi/h1/scripts$ ./Toggle_CS_Sensor_Correction.py -h
usage: Toggle_CS_Sensor_Correction.py [-h] ON_or_OFF

positional arguments:
  ON_or_OFF   1 or 0 to turn the gain ON or OFF respectively

optional arguments:
  -h, --help  show this help message and exit

Once the Sensor Correction is all disengaged, the STS masses are centered by pressing the Auto Zero button in the STS-2 area of the Outputs group.  This is a momentary and does not have to be pressed again to be disengaged.  The masses may also be monitored in the same area.

These instructions will be repeated in a FAMIS conditional task.

According to Matt's alog 26499, the 1/f^2 mystery noise needs to have an amplitude of about 1e-20m/rtHz at 100Hz.

With the ESD actuation function ( ~6.38e-8m/N * (100Hz/f)^2 ) this corresponds to a flat force noise of about Fc = 1.5e-13N/rtHz.

We can cast this into a voltage noise at the ESD F=alpha*V~2:
Parameters:
alpha-~2e-10N/V^2,
bias voltage V0-380V.

For the linear coupling this implies V = Fc / (2*alpha*V0) = 1.0 microV/rtHz.

In principle the quadratic nature of the ESD can also down-convert higher frequencies. For a band of white-ish noise with a bandwidth BW, the resulting force noise is F_DC = alpha * V_RF^2 * sqrt(BW). To produce the mystery noise through this down-conversion, assuming a noise bandwidth of BW~1MHz, would require ~1mV/rtHz at RF frequencies.

1115 hrs. local 

Exhaust check valve bypass opened, LLCV bypass valve opened 1/2 turn ccw -> LN2 at exhaust after 2 mins 10 secs -> Restored valves.  

Next manual overfill to be Friday, May 6th. 

When I started the ETMy Charge measurements today, I checked the Aligned state oplev centering.  It was WAY off.  So, I reset the alignment back to a more recent nominal pointing (based on trends) since yesterday's bootfest set all pointing biases to old values.  Note - we should reset to a good IFO pointing across all SUSes ASAP.

However this didn't help much on the Oplev which was out at some -90 in Pitch.  The long trend (attached) shows a major drift in the Oplev from ~March 20th to April 13th where it started to flatten out.  (Note there is a period of poor alignment for the week after April 13th, and then the pointing is restored, and the flattening out of the Oplev resumes.  Unsure of what tipped off the major drift, I checked VEA Temp - all good.  A check of the alog around the March 21st date indicated that the "grout work" finished around March 21st.  Wow, long grout dry time.

So, time to rezero!

WP5857 Keith, Rolf, Jim, Dave:

Tuesday 3rd May we upgraded the CDS front end systems and the DAQ to RCG3.0.2

The order of build-install was:

1. Clean out H1.ipc file
2. Compile all models (105 models)
3. Install all models into target area
4. Take down DAQ and recompile all DAQ code, restart DAQ
5. Reboot one SUSAUX FEC to test
6. Reboot all non-Dolphin FECs (SUSAUX, PSL, PEM-MIDS)
7. Put Guardian/IFO into safe state
8. Stop all Dolphin FEC models, reboot each computers. h1psl0 and h1seiex lost comms with their IOChassis and needed a power cycle.

During the make installWorld h1fs0 developed a major NFS problem and stopped serving /opt/rtcds file system. We reboot h1fs0, but the NFS service did not start correctly and clients could not umount nor mount the file sytem. We restart kernel-nfs-server daemon and the NFS clients remounted correctly.

I need to change the SUS ITMY and ETMY now the HWWD part is synced to the hardware regarding signal levels (I removed temporary NOT inverters on binary signals).

16:00 h1iscex developed the connTrack Table Full error, new network connections were not permitted. We have to reboot this computer and disrupt the EX Dolphin fabric, requiring all EX models to be restarted (except susaux).

Vacuum controls Beckhoff gauges on BSC7,8 were moved from their temporary slow controls Beckhoff connect to the LX vacuum controls system. This required a name change (H1->H0), minute trends were changed on DAQ.

Upgrade built ISI-HAMS with latest isihammaster.mdl file, but team SEI needed to back out this latest change, so common file was reverse-merged to previous version and all isi-ham rebuilt and restarted.

CAL system was modified to remove the Blind Injection data path (h1calcs and h1calex).

Big DAQ restart at end of afternoon: new VE EDCU list, new Slow Controls EDCU LIST, new Dust monitor EDCU list, new susitmy/etmy hwwd code, new isi-ham models, new cal models

The web view of the vacuum medm screens has been updated again to eliminate the now obsolete original overview screen and LVEA overview screen.

I am adjusting the CP2 LLCV PID parameters controlled by Beckhoff system. 

1. Set to manual mode at 35% open and adjust PI settings while in manual mode and observe value in data viewer real time. PI still updates its values in manual mode. Note that every time a PID value is changes the LLCV % open value resets.


The pneumatic actuator is physically jouncing up and down and will wear out prematurely at current Beckhoff settings. 

The new electronic actuator on CP1 is not jolting as much as CP2, but up/down movement is still noticeable at rapid rate - PID parameters should be addressed.

Have not surveyed the other five actuators (CP3 doesn't count).

Major activities:

- PSL work to restore the laser/alignment

- beam tube baking in LVEA

Activities for today- details:

- Christina - opening roll up door, LVEA receiving

- Jim - BRS

- Stefan - coil drivers

- Patrick - rotation stage - progress

- Peter - no damage but might need a major re-alignment

- Bubba - beam tube sealing continues

- Chandra - baking RGA through Friday

--- investigating a small anomaly in a vacuum gauge, likely electrical

- Stefan - log about wind and piping

- Recovery from upgrades yesterday looks good so far, but...

- Travis - p-cal calibration

- Cheryl - IM work, may see IMs swinging

- Karen and Christina in LVEA vacuuming and mopping

While I was at End X (around 7pmish) I heard repeaded banging noises coming from the GN2 pipes (GN2 BURST, GN2 VENT and GN2 REGEN). Not sure whether that's a know isssue, but it was rather loud, and the support piers were shaking noticably.

See also alog 26948. I repeated the L2 noise measurements described in alog 26948 for ETMX L2 and ETMY L2, as well as BS M2. For completeness I also added the ITM noise to this log.

The measurement conditions are the same as in alog 26948 (Acq Off, LP On, small 3kHz length drive).

Conclusion: no suspicius noise on the L2s (or the BS M2).

Plots 1-5 (in that order): ETMX, ETMY, ITMX, ITMY, BS

Plot 6: projection of the noise for the four main test masses.

Remark: ETMY features a 10Hz line, as well as a smaller 30Hz line. They seems to be real, and they have a different strenghts in the 4 coils.

Daniel, Dave, Nutsinee

The first problem with some TCS Beckhoff channels returned bad vaults was probably due to bad values in safe.snap file (I didn't know Beckhoff channels were monitored on SDF!). The second problem I ran to was the channels in TCS oaf model went bogus after the front end restart this morning. Dave burtrestored the values to where they were yesterday and everything seems fine.

Below I've attached the result of today's rotation stages random walk script to test the new Beckhoff control configurations for PSL RS (which was later applied to CO2 RS).

Quick Conclusion:

PSL RS requested angle and measured angle agree within 0.02 degrees (better than before).

CO2X RS requested angle and measured angle agree within0.03 degrees (better than before)

CO2Y RS requested angle and measured angle agree within 0.1 degrees (worsen)

I also increased the CO2 RS velocity by a factor of 30 and the acceleration and deceleration by a factor of 10 as Daniel suggested (3000, 10000, 10000).

And because of worsen the CO2Y RS performance the angle vs. power calculator is a bit off right now.