Reports until 18:43, Sunday 04 June 2017
H1 ISC
sheila.dwyer@LIGO.ORG - posted 18:43, Sunday 04 June 2017 - last comment - 16:10, Monday 05 June 2017(36645)
ALS work today

Summary: 

After swapping a few electronics that we broke while investigating the ALS glitches at EY, the glitches are still there, but not nearly as bad as they were.  We have had these glitches go away on their own before when nothing was done, so that might be what is happening.  Now they are at End X, and about as bad as they were at End Y for most of the week.  ALS still will not lock for longer than 10 minutes.  It might be that this problem will go away on its own, but will probably come back again.  

Things that are not the cause of glitches at EX:

From PLL bypass test:

Other things that are not the problem:

Things that we haven't checked:

I recommend that the first thing in the morning operators take the ISC lock guardian to locking arms green, wait there for 10-20 minutes, and look at second trends of the arm transmissions.  You can compare them to the screenshot I've attached here, if the glitches are gone or much smaller it would be worth doing an initial alignment and trying to lock to DC readout, if the glitches are still there it is not worth trying. 

Images attached to this report
Comments related to this report
daniel.sigg@LIGO.ORG - 08:24, Monday 05 June 2017 (36650)

A surprising number of the small glitches in Y align with bigger glitches in X. We should take a look at the fiber distribution.

keita.kawabe@LIGO.ORG - 09:07, Monday 05 June 2017 (36652)

zooming in you really can see that some of them are aligned.

Images attached to this comment
keita.kawabe@LIGO.ORG - 09:19, Monday 05 June 2017 (36653)

Fibers including ALS fiber with flapping tag. The fan of the network equipment is blowing directly on it.

Daniel pinged this and both arms unlocked. It's not clear this is the problem but it's not good anyway and will be fixed. (WP7015)

Images attached to this comment
keita.kawabe@LIGO.ORG - 10:24, Monday 05 June 2017 (36655)

Richard's solution was a yellow tubing around the fibers. A stuffed bag as a wind barrier is probably Daniel's thing.

After that the glitches seem to have been gone. We'll see if ALS survives longer than 10 minutes.

Images attached to this comment
david.barker@LIGO.ORG - 16:10, Monday 05 June 2017 (36667)

perhaps we can put the side panel on the networking rack. I suspect we left it off since the Cisco core switch is sideways venting.