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Archived Messages for KL_PI_NOTHING_1996@cebaf.gov: 4% Energy Resolution

4% Energy Resolution

Mark M. Ito (marki@CEBAF.GOV)
Mon, 19 Aug 1996 16:11:02 -0400 (EDT)

I've looked at the effect of having energy resolution of sigma_E/E =
4%/sqrt(E) on efficiency and rejection. Recall that the nominal value
that I used before was 2%/sqrt(E). You can find plots in the files

ftp://cebafb.cebaf.gov/pub/marki/neutral/scan_kpi2_02.ps
ftp://cebafb.cebaf.gov/pub/marki/neutral/scan_kpi2_03.ps

Let me call these Figure 2 and Figure 3. These are versions of the
efficiency plots I showed in Vancouver (they're in the AGS 2000
report). I've blown up the x-scale to display the region of
interest. Figure 2 is for 2% resolution, Figure 3 is for 4%
resolution. One interpretation is:

resolution eff for pnn rej against kpi2
---------- ----------- ----------------
2% 40% 50
4% 33% 50

i. e., to maintain constant rejection we give up 7/40 = 18% of our
acceptance. Not too good. Perhaps not crippling.

The constant efficiency is, as expected, not as nice sounding:

resolution eff for pnn rej against kpi2
---------- ----------- ----------------
2% 40% 50
4% 40% 20

i. e., to maintain constant efficiency we give up a factor of 2.5 in
background rejection.

--
Mark M. Ito, Thomas Jefferson National Accelerator Facility
12000 Jefferson Ave., Mail Stop 12H, Newport News, VA 23606
Email: marki@cebaf.gov, Office: (757)249-7175, Pager: (757)680-7175