Move flat planes, recalculate acceptance.

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After discussion with Jan and Walt, the last of the flat planes was moved to z=36 cm, which leaves a few cm for services in the back. Planes SI09 and SI10 stay the same, and SI11 is again placed halfway between 10 and 12.

Old positions here: phnxSili_flat_27feb06.par
New positions here: phnxSili_flat.par
[ look for 'sili_endcap_zflat']

The top red line shows the maximum angular acceptance for an event at z=-5cm and requiring 4 planes, the bottom red line the minimum angle requiring 3 planes, for an event at z=+5 cm.




Note that by moving the last 2 planes inward we improve the acceptance around 24-28° a little bit. requiring 3 or 4 planes.
This is the acceptance plot for the new geometry. For numbers, see the plotting script

Red and pink lines and shades are endcap boundaries, blue are the barrel boundaries.

Here is the same plot for the cone configuration.








Update June 2006:

This is a working drawing showing proposed positions of endcap layers, with nominal radii of 16 cm. This is before we negotiated some extra radial space. The colored lines show which of the 4 endcap layers define the acceptance envelope for different z-vertices.

This plot summarizes the acceptance, for tracks that hit all 4 endcap layers, for the 3 cases shown above.

acceptance_jun06.kumac
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Last update 27 June 06 - HvH