All components that are supposed to be installed in HAM6 in this vent were installed. I decided that the centering of the aux laser beam on the 1st iris was not great after all (1mm or so in YAW), so I realigned the laser to two irises carefully. This didn't have a huge impact on the downstream alignment, but it had some impact. Anyway, ASC-AS_C, WFS, OMC itself and OMCR path were readjusted.
See layout1, layout2 and layout3.jpg for the relevant paths including (but not limited to) things that were installed.
There are some caveats, namely,
- DCPD was super filthy and now it's just filthy. Do people clean this at all?
- Initially it looked like DCPD_initial.jpg. These spots are hard to see by eyes but easy to capture on camera.
- I used a puffer and it didn't make any difference. I used Vectra wipe with a mild pressure to wipe the glass cover and it became better (DCPD_1st_wipe.jpg) but not good. Second wipe didn't make much difference if at all (DCPD_2nd_wipe.jpg). Maybe some of these are inside surface of the glass? Anyway we gave up and installed this.
- One of the V-dumps we installed with thicker (0.5"?) post is just barely usable for a 4" beam height.
- See picture, the top of the metal holder for black coated steel is only 1/8" lower than 4". Inside the V, ghost beam flies 3mm above the shiny aluminum, reflected by the coated steel, flies above the shiny thing again, and again and again. This is not how we use V-dumps, you need a much shorter post. If we have a replacement post we'll use that tomorrow.
- We still need to calibrate OMCR DCPD using an integrating sphere.
- Couldn't see reflection of ASC-AS_C, so the beamdump location was just eyeballed.
- Couldn't see AR reflection of the lens for OMCR path, I expect that to fall on the V-damp for the 99:1 reflection.
Also, this is not a caveat, but there are three ghost beams generated by the OMCR DCPD because the glass isn't removed from the PD case.
Tomorrow we'll attack the above caveats in the morning and hopefully move on to OMC DCPD and PZT grounding investigation.
Hi Keita,
Is the OMCR DCPD punched from the side for venting? The glass cap gets cracked by the punch if the hole is too close to the window. The PD photos may be showing something white like a crack at the right side of the element. I had that problem for the DCQPDs in the past.
All of these are puched at Caltech, I believe. It's hard to interpret white things because it could easily be the lighting. We'll look closely.