[Bteam] 60 Hz - blame the injector! and the 5 sec blip is seen again

[Jay Benesch]

Shelley,

I wouldn't call it great news.

We don't know that the amplitude in the injector is larger than is usual.

We don't know why roughly equal amounts of 60 Hz in the injector planes 
become 1:5 amounts (x:y) in hall C.  It may be that FFB is doing the 
best it can in the vertical given the large amplitude.

We don't know why the FFB correctors don't have the expected calibration 
response given the (design) optics in the machine.  New calibration will 
be forced when the beam is restored this evening as the old curves were 
wiped out this morning by powering the system down.
I've checked the body gradients in the model against the measured arc 7 
values and there's acceptable agreement; they're tiny.  So that isn't 
the answer for the FFB response issue.

But then I'm a permanent pessimist.

Jay