[esa-t474] 1st DRAFT paper energy resolution

[Mike Hildreth]

Hi Michele,

	I understand that there are other resolution sources in the 
system.  Since you can measure 680nm, it might be interesting to see if 
the interferometer can reduce it (and if you can measure the differenc).  
The rms vibration was fairly large (BPM7 was worse...) so it might be 
visible in the distributions.  So, it won't change the resolution of the 
system except to make that one BPM better.

	cheers,

		Mike

On Thu, 11 Mar 2010, Michele Viti wrote:

> 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
> 

-- 
-----------------------------------------------------------------------
Mike Hildreth                 |   e-mail:      mikeh at undhep.hep.nd.edu
Department of Physics         |                mikeh at fnal.gov
225 Nieuwland Sciences Hall   |   telephone:   574-631-6458 (office)
University of Notre Dame      |                574-631-5952 (FAX)
Notre Dame, IN 46556          |   http://www.hep.nd.edu/MikeHildreth