The attached script is a quick calculation of the ABCD matrices from the MC waist and IM1, IM2, IM3, IM4 to PRM that Keita asked for yesterday. It is based on optics coordinates found in T080078-05  (written in 2008)  It doesn't take into account the angle of incidence on the curved mirrors.  
If someone from IO has done a more careful job or used more up to date coordinates, it might be useful to send a link. 

Cheers, Sheila

good alignment before ISI work			
4/9 7:00:00 to 13:00:00			

alignment before flashing IMC			
4/18 21:10:00 to 21:25:00			


--- HAM2 ISI ---
	9-Apr	18-Apr	diff
H1	-3860	-3300	  560
H2	-2270	-2670	-400
H3	    680	 -230       -910

V1	    712	  425 	-287
V2	    -81	-470 	-389
V3	-1728	  -90	        1638

calibration is 32768cts/mm		

PRM sees mostly V2 and V3		

1638 - (-389)	2027	counts

with calibration
0.062	mm

distance between V2 and V3		

49.5 inches	1257mm	

change in angle		

4.9324E-05	49	urad	

49urad at 16.5m			

0.0008085m	

---- punchline - tilt of the table causes 0.8 mm beam displacement at MC2/HAM3, and all numbers are within the stated spec. of 1600 counts change (well, one is 1628 counts).



--- HAM3 ISI ---

	9-Apr	18-Apr	diff
H1	-300	   -465	-165
H2	  175	     410 	  235
H3	  417	   -25 	-442

V1	-192	 -710	-518
V2	-450	 -430	    20
V3	  275	  290	            15

These numbers are much smaller than the numbers for HAM2.

---- punchline here is that this shows that changing the payload one HAM2 did change the position of the ISI table while it was locked.




----
Attached is a graphic of the table rotation, for HAM2 and HAM3, as I understand it.  Arrow length corresponds to the change, and can be compared between HAM2 and HAM3.

It is not occulting the POP-ALS beam path.

Summary:

MC alignment as well as IMs are very good. The beam hits the center of PRM and PR2. 

With this good alignment, when we steer PRM so that the REFL goes back to HAM1 without clipping, PRM alignment offsets are now 3395urad for PIT and 50urad for YAW. The largest DAC output decreased from -126000 counts (almost railing) to about -10750  -100750 counts,  so it's somewhat better but not that much. It seems like PRM really tilted.

At this point, PRM offset should be released, and after that right PRM offset should be re-established.

What was done:

1. Both pico mirrors and fixed mirror upstream of MC1 were used to center the beam on MC2 as well as on MC1 (mostly MC2).
2. MC2 was aligned so the single-bounce beam off of MC2 comes to a correct position in HAM2.
3. Used MC3 and MC1 to refine MC alignment. Excellent 00 flashes.
4. Used IM1 and IM2 so the forward-going beam goes through Faraday input and output aperture at roughly the same positions as before. No clipping.
5. Used IM3 to bring the beam to the center of PRM, and IM4 to center the bean on PR2, and iterate.
6. Align PRM to center the REFL beam on the baffle hole for HAM1 beam path.

Observation after the above:

• PRM PIT offset was reduced but it was still large.
• We didn't check if the beam was hitting PR3 (cannot, the beam is huge and the power is small), but the reflection off of PR2 was at a reasonable location in HAM3.
• The beam is too close to the center of the baffle in front of IM4. This is not a good thing according to Cheryl, as the baffle is designed such that when PRM is misaligned in YAW to direct the REFL beam to the parking beam dump, both the forward and backward (REFL) beams are equally away from the baffle edge. It seems like the baffle itself could move toward HAM1 by 2mm or so.

What was further done:

1. Misalign PRM to direct the REFL beam to the parking beam dump. PRM offsets railed and the beam was still not centered on the baffle hole for the beam dump.

What needs to be done:

1. Relieve PRM bias.
2. Align PRM so we have a nice refl beam again.
3. Confirm that we can misalign PRM to park the beam.
4. Move the baffle in front of IM4 somewhat closer to HAM1 and confirm that there's no clipping.

What doesn't need to be done:

1. Revisit beam paths to IOT2L viewports. It's impossible for these beams to miss the viewports by these tiny changes (tiny in comparison to the viewport size).
2. Revisit POP QPD sled (PRM-PR2 line is good), MC2 trans QPD (the beam is centered on MC2 so the transmission will hit the QPD), and SM2 trans QPD (lever arm is small so this change would not make the beam completely miss the QPD). We will use picos once things are under vacuum.

I took over from Pablo at 3, this is his report:

    LVEA
- Cheryl working on MC trying to understand some discrepancies
- Filiberto/Richard pulling cables and checking connectors
- Michael R. working in Pcal pre-alignment at H2 LAE
- Arnaud, BS TF ended around 11AM
- Thomas viewport alignment using 635nm, power <5mW laser

    EX
- Dust monitor alarm of 1800 PCF for > 0.3u, and 860 PCF for > 0.5u, possible cause Apollo work

    EY
- Thomas ETMY OptLevel alignment using 635nm, power < 5mW laser

Vincent restarted suspension/seismic models

We (JimW & I) locked up the HEPI to safeguard the ISI/SUS from external influences such as Walking Plate removal & Dome installation.  We found the Pier3 IPS unresponsive at -3200 cts.  We locked it up using the dial indicators.

BSC-ISI common model was updated. I modifided the master model and a couple of MEDM screens. Changes were commited (rev 4230 for model and re 4231 for MEDM screen). 

A correction was made on the T240 calibration gain and binary outputs block was modified to control STS-2s centering proccess. Overview and BIO screens were modified as well.

New codes were installed on BSCs 1 2 3 6.

Since further work continued in the chamber last week, the final chamber closeout had not been completed.  After checking for task completions for the final, final time, I went in and

1) checked for tools (none found, good)

2) removed the in-chamber stool

3) took a few more pix

4) re-inspected the naked BS optic (yep, dirty @ ~1-3 particles per square inch in many regions of both HR and AR face - some there prior to last week)

5) wiped my way out of chamber

6) placed verticle 1" witness optic under the BS suspension.

For the 35W beam.

The ISI-BSC2 (tested at the end of last week) is functional. The testing report can be found at LIGO-E1300292-v1.

I had to restart the IOC for the dust monitors in the LVEA due to communication errors. Cause is unknown.

Found cdsfs1 completely unresponsive, no display on console, no ability to log in remotely.  Powered off computer, removed and reinserted power cords, then powered back up.  After usual reboot, system came back, disk verify shows parity mismatches which are being repaired.

Belated alog for Friday activity after Cheryl was gone.

A good news is that Cheryl told me that the IM alignment was not good when we (Kiwamu, Sheila and me) found in HAM1 that the IFO refl beam was clipping on Thursday. On Friday Cheryl restored IMs and Sheila couldn't see any clipping of the beam going to HAM1.

But the bad news is that PRM still has a huge offset.

I think  it is essential to establish that the beam is actually at a good ballpark position on PR2. If the beam going from the last IM to PR2 has a reasonable angle and yet PRM is using up more than 90% of DAC range for PIT offset, one can conclude that PRM has a big natural tilt (though we don't know why). OTOH if the beam is not hitting PR2 or something, we have a bigger problem.

Cheryl told us that it should be possible to see the beam in front of PR2 if we have 00 mode flash. Since she also told that the straight shot beam (through MC1bouncing on MC2 and coming through MC3) looked good, I and Sheila tried to align MC using only MC1 and MC3 without touching MC2. We didn't do a thorough job, in the end we were still off in PIT (looked as if 10, 01 and 11 were dominant, but PIT had larger order modes flashing) but got 00 once in a while, but we couldn't see anything in HAM3.

Before giving PRM to SUS, the following should be done:

1. Align MC better. Note that the alignment offset of MC1 and MC3 are already kind of big-ish.
2. Use CCD camera and IR viewer card to see if the beam is on PR2.
3. Use CCD camera to see if the beam is hitting the baffle.
4. Use laser safety glasses for 1064nm. Our "official" glasses are totally utterly incompatible with IR viewer.

While Keita Cheryl and I were trying to see 00 flashed from the mode cleaner yesterday afternoon/evening, I ripped the door cover on the west side of HAM2.  It is a small rip (about an inch long) right by the clip on the north side of the door.  Since everyone had gone home and we didn't know where to find new door covers, we just covered back up when we left.  

Attached are plots of dust counts requested from 5 PM April 18 to 5 PM April 19.

Both HAM2 and HAM3 ISIs were locked this morning for alignment work. It was a good occasion to take look at the time series of the ISIs' Capacitive Position Sensors, and make sure that the locked/unlocked shifts were within requirements.

Maximum shift observed < 800cts*.The locked/unlocked shifts are within requirements**. Results are attached.

*:Calibration: 32768cts/mm

**: Acceptance Criteria (E1000309-v13, p28)
 Absolute values of the difference between the unlocked and the locked table must be below 1600 cts

April 10th between midnigth and 1am (UTC) (cf dataviewer trend attached)

M1 PRM Pitch offset  = 2000
M1 PRM Yaw offset   = 50

M3 pitch = 2000
M3 Yaw  = 115

Today with the same offsets (cf medm screen attached)

M3 Pitch = 1164
M3 Yaw   = -199

Beamsplitter transfer functions have been running over the weekend in order to fix any issues during the day if needed.

The attached pdfs show :

1. Comparison between last TF damping on and model
2. Comparison between last TF damping off and model
3. Comparison between LHO damping on/off and LLO phase 3a (feb 2013) TFs
4. Zoomed version of 3.

Vertical degree of freedom is noisier than expected between 1.5 and 3Hz (3rd page of each pdf).