From: Gleb Oleinik <oleinik@pizero.colorado.edu>
Date: February 11, 2010 4:18:50 PM PST
To: James Brau <jimbrau@uoregon.edu>
Cc: Uriel Nauenberg <uriel@pizero.colorado.edu>, Jack gill <jgill@pizero.colorado.edu>
Subject: Re: SB2009 stau analysis (fwd)

Jim,

We presented a similar series of plots in the paper here:

http://hep-www.colorado.edu/~uriel/Beamstrahl_TwoPhoton-Process/Efficiency_Study.pdf

or, in PS format, here:

http://hep-www.colorado.edu/~uriel/Beamstrahl_TwoPhoton-Process/Efficiency_Study.ps

These new plots are identical to those, except we've also shown the effects when the intensity of the beamstrahlung is multiplied by factors of 2 and 3.

Here's a brief overview of the what the plots show:

We electron showers on the BeamCal of with incident energies of 50GeV, 100GeV, and 150GeV, at polar angles of 0, 90, and 180 degrees. For each combination of incident energy and angle, there are four plots:

Electron_Detection_Efficiency_*GeV_phi*.eps
	Shows the electron detection efficiency for the given incident energy and
	angle, as a function of r, which is the distance from the outgoing
	beampipe center. Each plot has 3 curves, one showing the efficiency when
	the with the beamstrahlung intensity as it is according to the ILC 500GeV
	nominal parameters at SiD02, while the two curves show the efficiency when
	this intensity is mulitplied by factors of 2 and 3.

energy_*GeV_1x_*GeV_phi*.eps
	Shows average cluster energies for the given incident energy and angle as
	a function of R. So, each plot has 4 curves:

		1.'electron' shows the average energy contribution of just
		the incident high energy e- to the cylindrical cluster
		described in the paper above at the given (r, phi)

		2. 'overlaid' shows the average energy contribution of
		both the incident high energy e- and the beamstrahlung deposition at the
		given (r,phi)

		3. 'subtracted' is the same as overlaid, except the
		expected beamstrahlung deposition for that (r,phi) is subtracted from each
		cluster before the average is taken

		4. 'sigmaBeams_*x' is different, it shows the standard
		deviation of the expected beamstrahlung deposition for
		that (r,phi). As described in the paper above, we get the detection
		efficiency by comparing this standard deviation to the 'subtracted'
		cluster energy of each e- event: if the subtracted energy > 3*sigmaBeams,
		then we say the e- is detected, otherwise we say it is not. So, by
		comparing the 'subtracted' curve to the 'sigmaBeams' curve, you can get a
		feel for what the efficiency at that energy and angle should be as a
		function of phi.

energy_50GeV_2x_*GeV_phi*.eps
	Same as above, except the beamstrahlung's intensity was doubled.

energy_50GeV_3x_*GeV_phi*.eps
	Same as above, except the beamstrahlung's intensity was tripled.

So, 9 combinations of energy and angle, times 4 plots per combo, gives you the 36 plots.

The key conclusions are all illustrated in the plots labelled "Electron_Detection_Efficiency_*GeV_phi*.eps". The other plots are there to justify the efficiency results we've obtained.

-Gleb

On Thu, 11 Feb 2010, James Brau wrote:

Uriel,

These plots are very interesting.  However, I was hoping you
would prepare a brief summary.  It is hard to digest
the key conclusions from so many plots.

Thanks,
Jim

On Feb 11, 2010, at 2:17 PM, Uriel Nauenberg wrote:

Hi Jim:
   Can you summarize the reactions to our plots on the Beamcal resolution deterioration.
   Cheers,
         Uriel
nOn Mon, 1 Feb 2010, James Brau wrote:
It would be nice to summarize this in a few plots.  Could you do that?
Jim
-- 
Uriel Nauenberg
Prof. of Physics
Campus Box 390, Physics Dept.,
University of Colorado,
Boulder, CO 80309-390
uriel@cuhep.colorado.edu
Phone # (303) 492-7715
FAX   # (303) 492-5119