[Cheryl, Giacomo, Greg]

Using only IM1 and IM2 (under the assumption that the alignment done before the power outage was still good), we realigned the beam coming out of the (flashing) IMC to the fiducials we had downstream of IM2.

We initially used just the input and output aperture of the FI, obtaining these offsets

IM1 Pitch: 3000

IM1 Yaw: -1000

IM2 Pitch: -1410

IM2 Yaw: -1300

Then, we refined the alingment using IM1 to center on the iris past PRM, and IM2 to center on the iris in front of PR2. These were the offsets at the end of the process:

IM1 Pitch 2730

IM1 Yaw -170

IM2 Pitch -1380

IM2 Yaw -300

With this alignment:

- the parking beam reached the hole n the parking baffle with the same offset values for PRM (pitch = 2500, yaw = 50).

- the refl beam goes all the way back and easily clears the last baffle before entering HAM1

-the input aperture on the FI magnet is centered

- the centering into the AOE2 baffle is good (i.e. slighly off-centered, as neeed)

We are thus confident that we have realigned the beam out of the IMC to the beam we used before the power outage, and so all the resst of the alignment should be reasonably good.

Note that the beam appears to be slightly off-center (between 0.5~1 beam radii) on the output aperture of the FI, but we have no memory of how well that was centered before the power outage.

We then checked that the beam coming back from PR2 is reasonable centered on PR3. because the beam was scarcely visible and bigger than our target, we just scanned PR2 pitch and yaw to find the limit of visibility of the beam on the target, and then took the average. Our best estimate for PR2 the send the beam back to PR3 are:

PRM pitch = 1400

PRM yaw = 900

We then:

- re-centered the IMC REFL in the periscopes

- placed reference dog-clamps ad remove all the irises

- adjust a few baffles on IM2

- remove all loose/temporary IO hardware from HAM2.

We also went to remove the black glass from AROM RH6 in HAM3 (planning to either quikly find a way of cutting it, or just leave it out) to discover that the black glass had never been installed in the first place.

Attached are plots of dust counts requested from 5 PM April 8 to 5 PM April 9.

There seems to be a large spike in > .3 micron counts at end Y from ~ 2 AM - 3 AM, and a smaller corresponding spike at end X.

I measured the beam power at various points around the reference cavity (refcav) on the PSL table.
This is a part of the effort to increase the power of the beam that are distributed to the end stations through the fibers for ALS.

Apparently there is one point where we can easily squeeze more beam power out --- the half wave plate and PBS in refcav's AOM path. The PBS throws almost half of its incident power away at the moment (see the numbers below). So rotating the half wave plate will easily give us a factor of two increment in the entire fibers.

* * * * *  Measured Values in the AOM path * * * * *
Before the PBS in the AOM path = 36.0 mW
Transmitted light of the PBS in the AOM path = 18.69 mW
Reflected light of the PBS in the AOM path (blocked by a dump) = 15.20 mW

* * * * *  Measured Values at some other points * * * * *
Incident on refCav = 11.40 mW
Transmitted light of the refcav after the ALS Faraday = 5.69 mW
 

Keita, Kiwamu, Sheila

This afternoon we aligned the beam for the ALS doubling path from the PSL through HAM1 and out to the viewport for ISCT1.  

When we began Kiwamu saw that the beam was entering the light pipe nearly at the bottom of the aperture on the PSL side, although it was too high inside the chamber.  The top mirror of the periscope is mounted so that it can only move vertically, so Kiwamu moved it up slightly.  After that the beam that we saw in the chamber was probably a reflection off of the sides of the light pipe, but Kiwamu was able to recover by steering to get a reasonable beam.  After walking the beam in this way, we arrived at an alignment where the top periscope mirror is at the highest position possible.  On the PSL side the beam enters the light pipe slightly low (~7mm) and to the west (~5mm) in the ~75 mm aperture.   At the viewport in HAM1 the beam arrives slightly to the east of the center of the viewport (less than 10% off center) and the height is adjusted so that the beam hits the steering mirror at its center.  we then adjusted the position of the steering mirror (moving it less than an inch to the east) so that the beam is centered on it in yaw, and centered on the viewport heading towards ISCT1.  

We also considered looking at the alignment of the IFO reflected beam using mode cleaner flashes, but Cheryl told us that that beam will be moved later anyway when IM1+2 are moved, so we held off.  The high power beam dump we did not install because it is not ready yet, a part is missing.  

IAS (DCook, JOberling) setup for pitch & yaw alignment on the BS optic. IAS directed SEI to perform a CCW yaw of 400urad. JWarner did a 1/3+ turn of all HEPI Springs to go CCW. IAS then reported ~45urad CCW remained. SUS TSadecki continued to do Pitch adjustments and the Yaw number may change slightly. This CCW Yaw calculates to move the BS ~0.1mm -Y. Based on the alignment results of 28 March the BS was already 0.8mm -Y and it looks like we pulled it East (-Y) close to 0.1mm based on the Dial Indicators.  So, Jim did a very careful +Y translation (west) of ~1mm with the HEPI Springs.  Jim did two rounds of 1/4turn west of all Springs.Based on the Dial Indicators, this is what we ended up doing.

From the last time we did an Optical Table elevation/level check we have shifted up 0.1mm with only 0.03mm tilt over the span of the Optical Table.

From the X Y Z alignment (28 March) we shifted west 38mils & north 4mils.  The rotation imparted by the translation since Yawing the table this morning is 0.0urads.  Yes 0.0; the DIs all read the same translations implying no rotation measured--Good work Jim!

- Apollo removed east door from WHAM01.
- Laser safe at 10:00 am, Michael R.
- 10:15 am, PNNL called, vibroseis "shaker" truck now active.
- PNNL called last night @ 7:15 pm to notify of end of work, no answer from LHO.
- Alignment work at BS chamber, Doug and Jason, watchdogs tripped several times.
- Patrick T to Y-Mid station.
- NSF tour in the LVEA at 11:26 am.
- Cheryl transition to laser hazard 11:52 am.
- Kiwamy made power measurements in the PSL, ref cav path.
- Kiwamu and Keita working in the WHAM01, stop for today, will continue at a later date.
- IO group working in HAM02
- Hugh and Jim working at WBSC02, HEPI work.
- Cyrus R. to Y-End, x-End and X-Mid, switch work/installation.
- Betsy W and Travis S. to check do ground checks of SUS in chamber, WHAM02 and WHAM03.

Sheila, Keita 

Keita and I had another look at the power losses in the fiber distribution box (S1202528) 
According to the test report the Y end output was 8.4% of the input.  

We remeasured the power into and out of the box, input today was 1.72 mW, Sample output 190 uW, X arm 128 uW, Y arm 112 uW, Squeezer 90 uW.  (the Y arm output is 6.5%, so 25% worse than in the test report) 

We also tried to look up the insertion loss for the beam splitters, it seems as though the beamsplitters we have are custom and not listed on the website, but the max insertion loss that they list on the website for a beam splitter is 1dB.  Daniel says that the AOM should have 2dB insertion loss, so the combination of the 2 beamsplitters and the AOM should be 4dB of losses.  

Based on those numbers we would expect the Y end output to be :
0.8*10^(-0.4)*0.33=10% of input from PSL

We also checked that the LO to the AOM is 10.4dBm, the nominal value is 10dB, so that is fine.  

It seems like we will want some more power from the PSL if possible. 

After getting the timing restored, I started the x1ioptriple and x1sushxts05 models.  I verified that dataviewer can display signals, and diaggui can do excitations and view signals.  Let me know if something isn't running correctly.

This morning I found the servo driving the pumps at maximum voltage and only achieving 26.3psi rather than the 28 psi setpoint.  I backed off the setpoint to the usual past 26psi and the drive dropped to ~2000/2048.  Probably a viscosity change from temperature increase.  Seems normal.

[Cheryl, Giacomo]

The IMC is flashing again.

We did restart alignment almost from scratch, through the following main steps:

- Beam centered on the top periscope mirror on the PSL table, usign the bottom periscope mirror and the mirror before that

- Beam centered on the HAM2 periscope, using the top periscope mirror. This did NOT recover the original input beam pointing, as the spot reflected off of the input viewport into the external PSL wall are slightly offset. However, it did look nice as input beam alignment.

- Beam centered on the irises in front on MC1 and MC2 using the actuated and non-actuated steering mirror, respectively.

- Beam centered on the iris in front of MC3 using MC2

- Round trip closed using MC3 and MC1... and IMC flashing!

The MCx offsets are as follows (in um on the alignment offset sliders):

It's good to see that the big (and a bit worrying) offsets in yaw of MC1 and MC3 are gone...

Attached are plots of dust counts requested from 5 PM April 7 to 5 PM April 8.

The plots for dust monitor 4 in the LVEA are interesting. Perhaps the change was from turning on the clean room over the test stand?

In prep for IAS alignment upcoming, I uncovered the BS suspension and resuspended it.  I also removed the corner cube mount in case SEI wants to do any balancing/checkouts/etc. before we get onto alignment (i.e. payload is correct).

The laser was restarted today without any trouble. I took the chance to realign the PMC as well and gained about 400 mW. A quick measurement of the visibility gave 97%.

Also, I was able to start the VB spectrum analyzer program on the Beckhoff computer and we finally have an all green status screen.

While investigating lost frames, Tx/Rx errors and a non zero CRC for the Corner MSR L8_9 Vertex (EK1521) (the terminal for the fiber connection to the H1 electronics room), the h1ecatc1 computer froze and restarted. I had looked into the chassis housing this terminal in the MSR and had not seen anything obviously wrong with it. However, the error LEDs on the Corner MSR L2 (EL3202-0010) (the temperature probe readout) terminal were both lit. After the computer restarted I restarted the system manager and deleted the configured terminal for the connection to end X (it was disabled because it is not connected), and checked that scanning the modules gave an identical configuration. It did, and I put it in run mode and started PLC1 and PLC2. The previous errors with the EK1521 are gone, but the error LEDs are still red on the EL3202. I have not restarted the EPICS IOCs.

After fixing any loose dog clamps, and retorquing, Arnaud and I took B&K hammer measurements of the HAM2 PR3, PRM, and MC1 this morning.  We still need to do PR2 and MC3 (which has a temp IO alignment mirror nestled up against it's structure).  We took PR3 and PRM data with vibration absorbers on and off.  We only took MC1 data with the vibration absorbers on since they were already on and are difficult to remove and then replace.  Plots and statements to come.