Continuing PSL work ...

The pre-modecleaner transmission photodiode (D1002929 #69 S1107860) was swapped out for
another monitoring photodiode (D1002164 #62 S1107854).  The latter having its transimpedance
gain reduced from 20k to 3.3k.  This fixed the problem with the pre-modecleaner transmission
signal that is observed on the MEDM screen.  The calibration is correct to within one or
two watts.

In getting the power stabilisation up and running again it was noted that the amount of
diffracted light from the acousto-optic modulator was at most 1%.  Far less than what is
required.  Either the alignment for the AOM is off, which is quite likely, or the modulation
signal to drive the AOM driver is insufficient.

A plot of the measured AOM driver output versus modulation input is attached.  With the
0.457V from the power stabilisation servo, 24.6 dBm (320mW) was measured.  This may be
insufficient for the AOM which has an operational RF power of 2.8W (34.5 dBm).



Jason, Peter

C. Cahillane

I made a "calibration movie", or a gif of the entire O1 calibration for C01 and C02.
The darkest line is the current systematic error, and the dashed lines are the current uncertainty.  
Kiwamu made the helpful suggestion that I leave a trace of previous calibrations.  Previous calibrations are the light lines left behind from the dark trace.

You can imagine these movies as a trace over the spectrograms from LHO aLOG 26535.

I like this visualization of the high-frequency dither we see in our calibration.  Also this gives a good impression of how much our cavity pole affects us in the C02 calibration movie, since the cavity pole is the only time-dependent parameter not corrected for in C02.

For the LLO Calibration Movies, please see LLO aLOG 25647

Krishna, Michael

The winds have yet to pick up so we spent the past two days working on software upgrades. 

At ETMY, we integrated our previous PLC code into Daniel's template which will bring our code closer to standards. There was an error in the PlcInfoFB structure which we didn't know how to fix so we commented out the call in the main program. Also, the previous state initialization was re-initializing our variables on every loop so we disabled that function as well. Besides those two errors, the program runs as expected.

At ETMX, we upgraded the C# code to closely match the version we use at ETMY. The most substantial change is in the pattern to angle algorithm. The angle used to be calculated from the average difference of the collection of peak pairs which involved fitting each peak to a Gaussian. The new algorithm involves calculating the cross correlation of the patterns with respect to pixel shifts of the main pattern which is then fitted to a Gaussian. These changes reduce the computation required for each frame while also decreasing outside dependencies. We hope this new version will remove the bug which caused the previous code to crash periodically.

gathering free-swinging data overnight per WP5824

damping will be re-engaged tomorrow morning

Richard, Patrick, Filiberto

Beckhoff based vacuum control chassis and computer were installed at EY. Sorted out some issues with internal wiring for the 4-20ma inputs (LN2 gauges) inside the beckhoff chassis. Installed shorting plugs for the LN2 control valve watchdog. PT425, PT426, and PT427 guages were connected to the end Y vacuum chassis. We are still trying to sort out some issues with the readback signal for ion pump II411.

Fairly busy full day of Maintenace today.  The HPO work continues.  The hope is for beam to be back tomorrow.

Day's Activities

• 15:12utc (8:12am) Moving Dust Monitor, removing vacuum tubing for Dust Monitors, WP5822, and Dust monitor work throughout day (Jeff, Mitch)
• 15:13 Rebooting nuc0 & 7 (carlos)
• 15:25 MX liquid nitrogen arrival.
• 15:30 Japanese News Crew on site, WP5819 
• 15:30 Cleaning of EX & EY for next 1.5hrs (Christina/Karen)
• 15:40 EY to put in wedge in CP7 valve (Gerardo)
• 15:50 PSL photodiode investigation (PeterK & Jason)
• 15:57-19:50 EY vacuum transition work to Beckhoff, WP5822 (Richard, Fil)
• 16:03 HEPI rounds & seismometer check (Hugh)
• 16:13 Checking manlift/forklift batteries in LVEA (Joe D)
• 16:22 Snow Valley here for work at end stations, electrical maintenance on chillers  (John W contacted)
• 16:25 MY liquid nitrogen arrival; Kyle notified for set point adjustments.
• 17:15 BRS work at EY (Krishna & Michael)
• 17:20 Keita out to ISCT1 to check on PZT hardware
• 17:24 Adding filter to PI models (Ross, Tega, Dave B)
• 17:49 Paradise water
• 18:21 King Soft for samples
• 18:34 All out-buildings for Vacuum tasks (Kyle)
• 18:35 Japanese film crew in LVEA (Keita)
• 19:04 In-house vacuum cleaner discovered left running at MX.  Kyle turned it off.
• 20:00 Cheryl undamping IMs for free swing data over night WP5824 (Cheryl)
• 20:04 BRS Hardware check (Krishna, Michael)
• 20:07 Unplugging batteries (JoeD)
• 20:20 Restarting Beckhoff at EX (Patrick)
• 21:04 BRS team back out to EX for coding
• 21:15 EY Vacuum stuff continue (Richard & Fil)
• 21:16 HAM6 offset investigations (Jenne)

WP 5823

I have edited the h1lsc and common lsc models in order for us to be able to route the TR signals to the intensity stabilization system. As a result, the LSC model is now able to output a linear combination of TRX_NSUM and TRY_NSUM through a DAC. This signal can be then routed via an analog cable to the ISS, enabling us for a 3rd ISS loop.

To really engage this loop, one still needs to pull a few meter cable from the DAC output on the ISC field rack to the ISS module (either TRANSFER_1 or _2 analog input) in the same rack area. Additionally, to shave off undesired DAC noise above 10 Hz, we need an SR560 or equivalent in this analog path.

[Modification on the common lsc model]

 I have added two new outputs. Because the TRX and TRY were already acquired in LSC and properly normalized, only things I added are two "From" tags and two outputs. The modified version is uploaded to SVN. For LLO, they can just terminate these two outputs at the top level until they need these signals.

• Attachment 1 shows the two new outputs in the common lsc model.

[Modification on the h1lsc model]

I have added a new subblock called "PSL_ISS" in which I placed a matrix to combine the TRX and TRY signals and placed a filter. The output of this subblock is then routed to channel 11 of DAC0. Because DAC0 was occupied by an unused channel ALS_STATE_A, I have disconnected and terminated ALS_STATE_A. This should not impact on anything. The model is checked into SVN. After the installation of the new model, I checked the output signal with a voltmeter at the floor and it was doing what it should do.

• Attachment 2 shows the new subblock.
• Attachment 3 shows the DAC output

[Medm screen]

I made a medm screen for this new ISS loop. It is accessible from the PSL tab on SITEMAP. This screen is also checked into SVN.

• Attachment 4 shows the PSL pulldown tab on SITEMAP
• Attachment 5 shows the new screen.

Created system environment variable XKEYSYMDB and set it to 'C:/Program Files/Xming/XKeysymDB' (with backslashes instead of forward slashes).

http://www.aps.anl.gov/epics/tech-talk/2007/msg00075.php

Drove to end X and re-enabled it.

I noticed during my site inspection that the X-mid in-house vacuum cleaner was running for some unknown reason -> I unplugged it.

Chandra, Kyle 

Chandra noticed that IP8 had shut-down.  The LPC controller was displaying an error "High Voltage not detected" -> This error isn't listed in the "list of error codes" but was the result of a loose HV connector in the back of the controller -> Deenergized controller, reseated connectors, pwrd on - OK now.  

After a LN2 delivery the liquid level control valve setting was lowered to 18%, previous setting of 20%.

Per the Ops Daily Checksheet for Tuesday, I reset the following HEPI L4C Watchdogs:  HAM3, HAM4, HAM5, ITMx, BS, ETMx, & ETMy.

Have had this alarm since about 3:39am (10:39utc). 

(However, not sure what channels this is looking at.  HAM6 is hovering around 10^-5 Torr, but it's been trending low since yesterday afternoon.)

The light level on the first loop power stabilisation photodiodes was adjusted to
give ~9.6V on PDA and ~10.2V on PDB.  Other than (mis)aligning each photodiode there
is no way to adjust the output of each separately as the half waveplate is common
in both paths.

We tried engaging the power stabilisation servo without success.

The DC output voltage of the photodiodes reported on the MEDM screen are different from
those measured by a voltmeter.  Even though these DC values are calculated from the AC
output, once the value exceeds ~7V the discrepancy becomes quite large with 10V as
measured with a voltmeter being reported as ~6V on the MEDM screen.




Jason, Peter

The transfer function measurement of the frequency stabilisation servo are attached.
The unity gain frequency is ~180 kHz with a phase margin of ~25 degrees.  Recall that
because of the way the readout monitor ports are, the unity gain should read at -10dB.

The measured values are a little lower than what was measured with just the front end
laser running.  Although not too far off.

Not quite sure what the dip in the magnitude around 25.5 kHz is but it might be related
to the injection locking electronics.

The current gain slider settings are fast gain = 22 dB, common gain = 16 dB.  The output
of the RF photodiode is 50-60 mV locked, 230-320 mV unlocked.


Jason, Peter

Kyle, Chandra

Opened valves that were soft closed a week ago. 
GV 7 needed 40 psig. GV 5 needed 45 psig to open. 

Attached is plot of pressures on either side of each valve before and after opening. Before we realized to pump the gate annulus after a week, we had already set pressure against pistons to 20 psig, shifting gate slightly and releasing annulus gas into beam tube.

I have terminated the LO inputs to the AS 90 WFS chassis (as well as the cables that normally go to these ports), so that we can see if the dark offsets are more stable without the triplexer.  Later today, I'll swap the terminators to be at the front of the triplexer box, to see if that changes things.