[esa-t474] Re: Run 1421

[Yury Kolomensky]

	Hi Mike,

it is odd that the middle BPM has the smallest drift -- especially 
since we know it is flimsier than the rest. The sign of the drift 
appears to be the same on both ends, and from what I recall, we do not 
see drifts at this level from the BPMs (at least for the difference 
between x3 and x4). Is there any chance the optical path is drifting, 
or there is some other problem in the interferometer hardware ?

Yury

On Jul 21, 2006, at 1:30 PM, Michael Albrecht wrote:

> I've been able to access a few of the data files and pull out the 
> interferometry data.
> Here's a link to some plots I've generated from Run 1421 ( a 20k event 
> stability run), both long term and zoom-in plots of each end.
> http://www.nd.edu/~malbrec2/interferometry/run-1421.html
>
> It appears there is a 600 nm drift in the mean value of BPM 3, a 500nm 
> drift for BPM 5, and just a 25nm drift in the mean value of BPM 4 over 
> the course of the run.
> The RMS values, on the other hand, stay fairly constant.
>
> -Mike A.
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