Reports until 18:30, Thursday 05 June 2014
H1 ISC
keita.kawabe@LIGO.ORG - posted 18:30, Thursday 05 June 2014 - last comment - 13:15, Monday 09 June 2014(12242)
HAM6 today (Dan, Corey, Keita)

All optics except two steering mirrors (one behind OM1 and one close to OM1) were fixed down to the nominal position. We need to move these two steering mirrors tomorrow.

Two V beam dumps are to be installed tomorrow.

OMC was freed, OMCS BOSEMs were centered.

OM1 was freed, OM1 BOSEMs were centered.

OM2 and OM3 are going to be freed and BOSEM centered tomorrow. Damping magnet gap for all Tiptilts are to be set tomorrow.

All 5 QPDs, WFS(DC) and OMCDCPD will be tested tomorrow.

Detailed alog will follow.

Comments related to this report
keita.kawabe@LIGO.ORG - 23:59, Thursday 05 June 2014 (12243)

Details: WFS path was made different from documents (documents are wrong), small difference from LLO.

Have found that all HAM6 layout drawings are wrong about WFS position. The distance from the lens on the sled to WFSA should be 191mm and WFSB 475mm (T1000247), but layout on documents like D1000342 both of them are about 3.5 to 4 inches too short. This is not a problem for WFSA because there is a room to move it, but moving WFSB back to gain extra 3.5 to 4 inches would make WFSB base interfere with one of the balast masses on ISI.

LLO originally changed the sled layout (see alog 2888), Corey didn't know about it when he made the sled (Corey's alog 12083), but anyway we thought that this was how LLO did it, and making this change would require swapping both of the mirror mounts (from left handed to right handed) which sounded like a hassle, so we decided to move the steering mirror M102 for WFSB as well as WFSB itself about 3inches downstream to the west. Later I found that LLO installation look more like D1000342 (see the picture of alog 8224), it's hard to see how it was exactly done but I'm asking Chris and Valera.

Some measurements:

  • L101 to WFSA 191mm nominal (T1000247), 192mm measured.
    • L101 to the first steering mirror M101 is 57mm, M101 to the WFSA is about 135mm.
  • L101 to WFSB 475mm nominal, 476.5mm measured.
    • L101 to M101 is 57mm, M101 to M102 is 358mm, M102 to WFSB 61.5mm.

There's some uncertainty in where exactly the diode face sits, and the accuracy of the above is probably something like +-2mm.

keita.kawabe@LIGO.ORG - 00:10, Friday 06 June 2014 (12244)

Details: AS_C QPD (not sled) had a smudge and was swapped

Fresh out of the bag, there was a smudge on the AS port QPD window in D1101654 S1202409 QPD/cable assy, and it was very close to the center. We didn't have to use any special light to see that it's there, but we needed to look at it from a certain angle.

I attempted to clean it on the spot using a wipe and alcohol, but it didn't go away, maybe it's some kind of scratch or abrasion. It's probably fine for some other purposes but I didn't want to put it in the AS path.

We pulled the QPD out of the assy and dropped the spare QPD in.

For future rerefence:

Bad IR QPD: #8. This is stored in a bag, not in the spare QPD cage.

Replacement IR QPD: #18

We have now only one spare IR QPD in the spare QPD cage, which is #15.

But we still have one spare IR QPD cable assy pre-assembled with two QPDs.

keita.kawabe@LIGO.ORG - 00:33, Friday 06 June 2014 (12245)

Other details:

Confirmed that serial # of OM1 TT stage is 002, OM2 004, OM3 033, as per Rich's alog 8612.

I didn't like the way OMC REFL beam diverter (BDV1) was assembled, as the peek washers face upstream. There's some (admittedly small) possibility that they are burnt when three things happen at the same time, i.e. IFO loses lock, TT or OMC is shaken, and the fast shutter is non-existent or malfunctioning. Flipped things such that these washers are downstream of the black glass piece, but Corey found that with this new configuration the beam diverter will interfere with balast masses. So, unhappily I flipped everything back.

At LLO two dedicated beam dumps for beam diverters were installed (Chris's alog 7573), we need to copy it.

koji.arai@LIGO.ORG - 13:15, Monday 09 June 2014 (12263)

IN-VACUUM DCQPD LOCATION MAP E1101174-v13 updated accordingly.