Peter K, Sudarshan, Gabriele

All the eight photodiodes are now acquired with the temporary break out box, allowing us to measure the direct output of the transimpedance. 

We could finally find what we believe is the real beam, since we got high power on all photodiodes and also on the quadrant. However, we've not been able to find a position that simultaneously center the QPD and maximize all the photodiode signals. We can either center the QPD or maximize one or few of the photodiode signals.

For reference, we have now

QPD = 22000 cts, 13 V

PD1 = 4170 cts = 2.54 V = 2.1 mW
PD2 = 4500 cts = 2.75 V = 2.7 mW
PD3 = 4620 cts = 2.81 V = 2.3 mW
PD4 = 5000 cts = 3.05 V = 2.5 mW
PD5 = 4840 cts = 2.95 V = 2.4 mW
PD6 = 4320 cts = 2.63 V = 2.2 mW
PD7 = 5120 cts = 3.13 V = 2.6 mW
PD8 = 5000 cts = 3.05 V = 2.5 mW

There is an excursion of about 20% from the minimum to the maximum. For sure, the present position does not correspond to one that minimize the jitter to RIn coupling for each diode separately. We tested that adding a slow 1 Hz modulation  in pitch or yaw on IM3 does introduce a fluctuation in the PD signals. The effect is particularly large in yaw, and much smaller in pitch.

Installed new high level controllers into the HAM5 ISI this afternoon. After some normal amounts of fiddling I have them working about as well as HAM3 (see attached performance spectra, blue is HAM3, the unlabeled red trace is HAM5). There's no feed-forward or sensor correction installed yet, so there's probably room for improvement. But for the moment, I hope it's good enough.

Aidan.

I set the SYNC frequency (the frame rate) for the H1 ITMX HWS to 1Hz rather than the default 57Hz. This was done by accessing the serial port of the camera, making sure the frame rate was set to 1Hz and then entering the command wus to "write user settings" to the camera.

I confirmed this was working by rebooting the camera and verifying that the frame rate returned to 1Hz.

See the attached screen capture of the command window I used to do this.

(I also turned off the HWSX SLED).

Aidan.

I removed the LEXAN cover to help locate the conjugate plane of the HWS by the ITM. This test was performed in the following way:

1. Removed Hartmann plate from CCD to get a simple capture of the return beam

2. Added a 50mHz, 4 micro-radian amplitude oscillation to ITMX YAW

3. Captured a series of 100 frames on the HWS, running at 1Hz. Measured the centroid of the overall intensity pattern for each frame.

4. Plotted the centroid vs time. 

5. Determined the <pk-pk> size of the oscillation in the centroid in pixels.

6. Determined the conjugate plane of the HWS near the ITM (or conversely, the conjugate plane of the ITM near the HWS).

<pk-pk>*magnification_of_HWS_optics*pixel_size = oscillation size near the ITM

The goal was to move the HWS along the optical axis until the <pk-pk> size was minimized.

The best I could do was:

<pk-pk> = 0.2 pixels

M = 17.5x

pxiel_size = 12E-6m

Therefore the oscillation size (peak to peak) by the ITM is 42 microns. The peak-to-peak angular change is 16 micro-radians for the reflected HWS beam. Therefore:

the HWS is within 2.6m of the conjugate plane of the ITM.

7. The last step was to replace the Hartmann plate on the sensor and move it an additional 10mm along the optical axis. (The Hartmann plate is mounted 10mm in front of the CCD and this action places the conjuate plane on the Hartmann plate rather than on the CCD).

The X1 accumulation was done from July 29 through August 1.

I get the N2 leak rate as <6e^-9 tl/sec and the hydrogen outgassing as 1.1e^-14 tl/sec/cm^2.  Corrected to 20C the hydrogen outgassing will be less.

The N2 rate assumes all of AMU28 is N2 but much of it may in fact be CO.

The RGA calibration was assumed to be 319 torr/amp.

X2 accumulated from Sept 18 through Sept 22.

N2 leak rate is <4e^-9 tl/s

H2 outgassing is 5.9e^-15 tl/s/cm^2.

The RGA calibration is assumed to be 319 torr/amp.

No temperature data was taken for this module. My guess is the average tube temperature has been 25C.

These are working again. We needed to align things on the table, as it was previously done with some random alignment.

The filter gains are +500000 counts for WFSA PIT/YAW and WFSB PIT, but -500000counts for WFSB YAW.

UGF is 10-12Hz for WFSA and 8Hz-ish for WFSB with these gains.

DAQ was restarted. Two changes:

• H1EDCU_HWS.ini created and added to DAQ master.
• H1BROADCAST0.ini two additional PEM channels added, requested by John Z.

The Hartmann sensor on ITMX measured the RH thermal lens in ITMX when 6W was applied to the RH. I'm satisified that it is installed correctly. 

We need to install a beam tube between the viewport and the HWS table so, currently, the LEXAN cover is installed over the viewport (it was removed for the RH test).

The attached plot shows the measured HWS spherical power when 6W of RH power is applied. A negative lens starts to form about 10 minutes after the heater is first turned on - as expected. I turned the heater off after 35 minutes or so as this was all that was necessary to confirm that the sensor is working. Just after I turned off the RH, I replaced the LEXAN cover on the viewport (this is why the signal goes haywire).

Summary:  The hauling of Hanford's orange rubble containers along Stevens Drive, through the nearby Wye barricade and onto the Hanford site continues to produce lots of 1-3Hz seismic noise at LHO on day shift and swing shift.  This circumstance might not change much during the remainder of 2014.  The swing shift noise might decrease in 2015.

History:  Hanford site activities that LHO feels the most are expansions of ERDF (the enormous rubble depository ~11 miles from LHO), the hauling of ~20-30 ton waste containers to ERDF and the return of empty containers out of ERDF back to the remediation locations.  Pit expansions only happen when an existing supercell (hole) becomes full every few years.  The excavation of a new hole takes a few months.  The hauling of containers through the nearby Wye barricade is continuous.  See  this elog entry for some S6 plots of truck traffic.

Current status of hauling activities:  On a typical day between Monday and Thursday, 200-300 container trucks will pass through the Wye barricade on Hanford's day shift.  300-400 trucks will pass through the barricade on swing shift.  The empty/full ratio for these totals usually lies within 30% of 50/50.  [NOTE:  These totals represent the highest possible values.  The actual totals might be lower because not all trucks in the total might travel on Stevens Drive.  Some might travel to other Hanford remediation areas on the far side of the site.  This is one of several possible uncertainties in the haul numbers that I've received].  There is occasional weekend activity, but it doesn't appear to be significant.

Operations schedules and interruptions: The trucks haul containers on both day and swing shift, but ERDF only operates the pit during day shift.  The baseline schedule for the pit is four ten-hour days, but the pit will operate and loads will travel on Fridays as needed to catch up from lost time.  The pit will shut down during high-wind episodes, but there's not a hard mph threshold for shutdown; wind direction matters.  Pit operations also might halt for unusual circumstances related to particular loads.  Although the pit might close in high winds, it's possible that loaded trucks could continue to travel since the containers are covered.  It appears from the load numbers I've received that reduced pit activity correlates with reduced travel activity.  These reductions are most evident on intermittent Fridays.

Future activity:  Day and swing hauling through the Wye barricade apparently will continue through the fall as crews continue to remove material from Hanford's 300 area north of PNNL and from the 618-10 area that's on the south side of Stevens between 300 and Energy Northwest.  Hauling projections in part appear to be based on funding projections, which tend to fluctuate.  Current circumstances suggest that the total number of loads in the winter will drop to a couple hundred per day, and it's possible that swing shift hauling could cease in 2015.  Long term:  The 618-10 site will remain active for several more years, and the 618-11 site near Energy Northwest's facility will ramp up and become active over the next couple of years.

Attached plots:  The PDF contains a set of recent 24-hour plots that start at 6:00 PM local time each day. These show the X and Z channels at EX in the 1-3Hz band.  The last two plots are Fridays.  9/19 seems to show that the trucks were traveling in groups.  8/15 shows a moderately busy day shift and a quiet swing shift.      

Aidan. Greg.

The ITMX HWS probe beam is now aligned to the test mass. Or rather, it is misaligned just enough to prevent a return beam from the ETM getting back to the HWS.

The conjugate plane of the sensor is within approximately 5m of the ITM HR surface (details of this measurement to follow).

The Hartmann plate is installed on the sensor and it is now running the HWS code. The code is broadcasting EPICS channels but is throwing up a warning about not being able to write the centroid data to file (I'll need to fix this).

I've now set the ITMX RH to 6W for a 45 minute test to confirm that the sensor is actually measuring something from the ITM and not some other spurious signal.

I did turn the table HEPA filter back on just before this measurement, so the temperature is dropping significantly on the sensor (which looks like a small change in the thermal lens)

Peter K, Sudarshan, Gabriele

With 160 W of power at the input of the IMC we expect 125 W at the IFO input. The beam sampler in transmission of the IMC collects 300 mW, of which 250 mW goes into the ISS array.

Therefore, with the present 10 W at the IMC input, we should have 15.6 mW into the ISS array. Of this, 1% of 50% goes to the QPD, corresponding to 78 uW on the QPD, and 1.95 mW on each photodiode.

The signal on the QPD should be 75 uW x 0.75 A/W x 100e3 V/A = 5.5 V or 9100 counts

The signal on each photodiode should be 1.95 mW x 0.75 A/W * 1600 V/A = 2.4 V or 3900 counts

SEI- Hugh running TFs on HAM6. Jim working on isolation filters on HAM5

SUS - work on quads for 3IFIO; last assembly almost complete. TMONS left to build.

TCS - X arm aligned. Viewport covers will be removed for more accurate alignment. Y-arm: wrong lens installed in vacuum - no point in trying to align at this time

CDS- cabling for aux systems continues. building RF box for 3IFO.

Commish - cont. alignment of DRMI this weekend.

I found the laser status screen indicating the "WARNINGS" had triggered.  Went to the diode room to investigate.  Found "NPRO switchoff during run"
illuminated.

I reset the laser, everything returned to normal.  I have to look up what the error message means as I do not recall what it was for.  There is
no evidence of the NPRO dropping out over the past 48 hours.  Attached is the trend data for the past month.  No signs of the NPRO tripping out.

Maybe a glitch set it off, or either the insertion of the reference cavity heater card or the outer loop power stabilisation card.  Will check
again on Tuesday to see if the condition crops up again.

no restarts reported

As preparation for automating the initial alignment, I did some things associated with the X arm locking.

(LSC-TRX_A_LF path was realgined at ISCTEX)

After the PSL light was locked to the X arm, I realigned TRX_A_LF path in order for LSC to be able to do triggered lock acquisition. The beam was already hitting the center of the bottom periscope mirror from the beginning. I steered the bottom periscope mirror and some optics in the down stream. I found that a lens had been taken out  presumably due to the previous QPD work in this past July (see alog 12672). There was a post holder and a base plate secured on the table in front of the bottom periscope mirror. Looking around, I found a 2 inch lens (PLCX-50.8-515.1-UV-1064) with a post laid on the table. So I inserted it to the post holder and looked this was the right lens as the beam nicely converged towards the photo-diode (Thorlabs PDA100A).

Also, I put a temporary steering mirror aside. This is one of the mirrors that Sheila placed in this past July (alog 12672) and has been blocking the PDA100A. The DC voltage coming out from the PDA100A was about 300 mV with a 00-mode transmitted light on it.  I did not check the gain setting of the PDA100A. The ADC count reached 1x10⁴ cnts when the arm was locked on a 00 mode. Probably we will need to decrease the gain of the PD or that of the interface box at some point in the future in order to aviod saturation.

In addition, I adjusted the trans camera. I needed to move a black-place beam dump closer to a beam splitter which is the one before the PDA100A. Then I steered the beam splitter and the angle of the camera to coarsely center the beam in the view. I could not identify the channel number for this signal at the video matrix in MSR. Looks like channel #53 is it, but it keeps flickering for some reason and therefore hard to tell. Though, a 00-mode beam was visbile ocasionally. We need to fix this in the day time tomorrow.

(IM4/PR2 alignment with REFL9 WFS)

Instead of aligning IM4 and PR2 by hand, I started doing it using the REFL WFSs. I used REFL_RF9_A and _B and they worked well. Once I zero-ed the electronics offsets in the RF9 demodulated signals,they started looking reasonable. I closed two loops by feeding the A_RF9_I signal to IM4 and the other to PR2. IM4 turned out to be a well-diagonalized actuator in the sense that it was able to actuate mostly on the WFS_A signals. On the other hand, PR2 had some cross-coupling which is not surprising at all. I need to work on this a bit more in order to have more diagonalized servos. I did not precisely adjust the gains. So these are the remaining tasks.

Anyway, closing the loops increased the transmitted light and reduced first-order coupling from angular fluctuation of some optics. Note that I had the DC centering servo running in order to keep the spot centered on both WFS_A and _B.

Baffle PDs, now with the correct labels:

Especially in pitch, these are rather different from what we found yesterday, which is not too suprising since we were hitting the ITM somewhere far from the center yesterday.  There is a beam at the end station coming back from the ITM, and some fringing at ISCT1.  To be continued....

Gabriele, Peter K., Daniel, Sudarshan

HAM2 Picomotor Channel List:

From our capacitance measurments (LHO: alog 14148), and the cable specification drawings: D1000581  and D1101515, we concluded that the picomotor on HAM2 are connected to the following channels:

Channel        Picomotor

1                     ISS (PM1-closer to the array)

2                     IM4 Transmission QPD 

3                     Faraday Half Wave Plate

4                     IMC Input Pointing

8                     ISS (Before the telescope) 

5, 6, 7             Empty

This is consistent with the channel assignment at LLO alog 12174

During the process we moved the Faraday HWP (Channel 3) and IMC Input Pointing (Channel 4) quite a bit, but we brought it back to its original position, atleast on theory. We moved these the same number of steps back as we moved forward and viceversa. :)