[esa-t474] 1st DRAFT paper energy resolution

[Michele Viti]

Mike Hildreth wrote:
> Hi Michele,
>
> 	One question: since you are looking at trajectories - we still 
> have the capability of seeing if the application of the zygo measurements 
> of the BPM4 position can improve its resolution.  How hard would it be to 
> do that?  In skimming through your note, I didn't see that...  In 
> principle, it's a matter of shifting a single time delay of the zygo 
> position extrapolation to minimize the BPM resolution.  Any ideas?
>
> 	thanks,
>
> 		Mike
Well,
As far as I understood (from the BPM paper) the interferometer system 
can correct for vibration of the entire system and for the non-rigid 
body motion (the movements of the single BPMs)
For the BPM4 was found a value of ~680 nm. Taking into the account an 
offset of 5 mm, if we do not correct for this we get an error of 680nm/5 
mm = 1.3*10^-4.
Since we are not still close to this value I'm not sure that applying 
the zygo interferometer data we can improve.
The results from Alexey (who found a better beam energy resolution than 
what I wrote in the note) must be confirmed.
I hope I understood correctly your observation.

Michele