Daniel, Nutsinee

After Daniel made some changes to the RS configurations today (alog27008), I ran the random walk script again. 

Result:

CO2X RS requested angle and measured angle agree within 0.01 deg -- Better than ever

CO2Y RS requested angle and measured angle agree within 0.02 deg -- Better than ever

And PSL RS requested angle and measured angle agree within 0.004 deg -- Awesome!

I have also recalibrated the power vs. angle calculator for CO2 RS.

Suspect Beckhoff work again.

Bit the bullet and started adjusting the 4f lenses.  The beam profile currently is a
little better than the attached image.  The output power as measured with the power
meter located near the external shutter is ~151W (~148W on the external power meter).
All powers are with the corona aperture in.

    Adjusting the homogenisers and fibre bundle positions did not yield the breakthrough
in output power I was hoping for.

Tega, Ross, Jim, Dave:

here is an overview of the signal flow to get the OMC DC-PD signals from the corner station to the SUS-PI models at the end stations. For example, lets take the ETMX system:

h1lsc0 front end computer:

h1omcpi model (running at 64kHz). The OMC DCPD A and B ADC signals are downconverted into four pairs of I and Q phase signals. These 8 signals are transmitted out of h1omcpi as local SHMEM IPC channels.

h1omc model (running at 16kHz). The 8 SHMEM IPC signals are received, and MUX'ed to a single channel. This channel is split and sent out as an RFM channel on the X and Y RFM loops.

h1iscex front end computer:

h1pemex model (running at 16kHz). The RFM signal is received, and sent through a 1-to-8 DEMUX. The time delay of 1 cycle is compensated for. The resulting 8 signals are sent as 8 Dophin PCIe IPC senders.

h1susex front end computer:

h1susetmxpi model (running at 64kHz). The 8 Dolphin channels are received and upconverted.

State of H1:  PSL is being realigned, no light to the IFO

Activities:

• Fil Ed EY pull cables
• Peter Jason PSL realign
• Chandra Richard LVEA vacuum gauge
• Kyle Stefan EX noise hunting
• Travis TJ Evan EX pcal
• RichM ITMY testing
• Kyle MY and MX drilling
• Hugh SEI ITMX and BS
• Betsy EY charge measurements
• Travis TJ Evan EY pcal
• Betsy EX charge measurements
• Nutsinee TCS testing rotation stage
• Stefan ECR-LVEA-EY-EX coil driver measurements
• RichM EX collecting data - ongoing
• Nutsinee PSL testing rotation stage - ongoing

Summary:

Cable routing from ISCT1 to ISC field rack 2 (R2) didn't make sense with or without the flipped connector reported yesterday (alog 26970).

Routing was fixed, WFS was connected to the demod, and it seems like everything works as far as the electronics is concerned.

But we still have whitening BIO problem (alog 26307), so we can only use odd dB gains (3, 9, 15 etc.).

Next step would be setting up the optical path.

Cable routing error:

Before I started working, the cables between the ISCT1 and ISC R2 were routed as follows:

"Test" input on the patch panel was routted to 9MHz CH4 output. Also 9MHz and 45MHz were mixed up. Don't ask me why.

Rerouting:

Hi- and low-frequency and test mixup was fixed at the ISCT1 feedthrough because it's easier than at the rack.

At the rack, high frequency patch panel (45MHz, R2 position 11) is at lower position than the low frequency patch panel (now 36MHz, R2 position 9), but our POPX patch panel and demod are at the bottom of the rack. Moving cables from high position to the bottom looked more cumbersome than from low position to the bottom. 

For this reason, cables at the ISCT1 feedthrough were rearranged such that 45MHz cables go to higher patch panel and 36MHz cables to the lower one, and 36MHz cables at the rack were moved to the bottom patch panel. I also moved 36/45MHz test input cable from position 11 to the bottom because it was easy though I didn't have to.

Anyway, in the end this is what I ended up with:

POPX 36MHz signals were connected to POPX WFS demod at position 3.

Signal check:

Used a flashlight and confirmed that all four quadrants respond in DC on MEDM.

At the field rack, I injected a 36.4MHz-ish signal to test input, and confirmed that all eight demod outputs (H1:ASC-POPX_RF_I1 etc.) change by about the same amplitude and at the same frequency.

Measured the TF from the test input to the RF monitor output of the demod, and confirmed that the amplitude at 36.4MHz for all four quadrants agree within +- 0.02dB or so.

Notch frequency were 45.39, 45.56, 45.71 and 45.92MHz for quadrant 1, 2, 3 and 4 respectively.

With the ring antenna and the battery powered scope I chased down the time-domain transients that I observed on the L2 coil cable (10msec burst every 100msec). They are due to the RFID tag, and get huge close to the RFID stations (35Vpk when the antenna is held close to the RFID board).

Attached are 4 scope traces, as well as a 3MHz span spectrum. The frequency content is 124kHz plus (mostly odd) harmonics. The y-axis is arbitrary, as the gain depends on the distance from the source.

Turns out that the rotation stages are sufficiently different that the same parameters won't give optimal results. In particular, the CO2Y rotation stage seems to require significantly more current for the same velocity.

For TCS I reduced the maximum speed even further, since it is unlikely that we ever need high speed. The maximum is now about 100 times slower than originally. The speed can simply be left at 100% with 10 sec acceleration and deceleration times. I also needed to reduce the PI loop gains by 2 for X.

I noticed that the motion always falls short of the final destination. For large angles the errors tend to be somewhat larger. I added a fine adjust feature which, when engaged, will nudge the motor, after it finishes its initial motion. This feature includes an adjustment angle which is intended to compensate for the shortfall.

The busy flag gets stuck quite often, and the auto-abort is required for the fine adjust feature to work consistently.

In order to connect the duty cycle and current readbacks, the 0x1A07 and 0x1A09 regions need to be assigned in the process data configuration of the motor terminal. This will add "DCM Synchron info data channel" structures which contain the info1 and info2 channels.

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.

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).

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.

The attenuated output from the front end, or seed, laser was admitted into the high
power oscillator ring.  No signs of clipping on the intermediate optics was observed.
However the overlap between the beam promptly reflected from the oscillator's output
coupler and the beam that traversed the ring was slightly off - the interference
fringes were clearly left of centre.  This was corrected for.  The mis-alignment of
the output coupler was most likely caused by the drag wipe cleaning the previous day.

    Each laser head was powered up with 5A of pump current.  No bright spots were
observed on the optics that would indicate some kind of point damage.  Each head was
powered up to 50A and again, no point damage spots were observed.

    The oscillator was then fully powered up, starting at 40A-45A per head.  The
laser power was noticeably down.  The beam from the oscillator, shown in
FirstTurnOn1.png, was ugly but stable.  My interpretation of this was that there
was no point damage on the optics but that the resonator was severely mis-aligned.
The exact reason for why the resonator would have become mis-aligned is not clear
to me.

    Adjusting the output coupler did improve the beam shape but not the output
power.  A more thorough alignment process will be embarked on tomorrow.