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PLACEMENT ACCURACY IN Z

In this section I assume that each strip detector panel has a random small deviation in z as it is glued onto the cage.

(postscript version)
This picture shows one fully populated outer barrel face, with 12 strip detectors placed on it. If you look closely, you can see that the panels are randomly displaced in z (horizontally in this image). The shifts have a maximum of +-0.5 mm, so that they do not overlap or hang off the sides of the individual rohacell cages (cages not shown).

With the panels thus jumbled, I did a run and found that the vertex-finding efficiency had dropped to 59%.

This plot summarizes the vertex-finding efficiency as a function of the maximum random panel displacement. Dotted lines indicate a 5% and 10% losses in efficiency, for z-placement tolerances of 0.08 and 0.16mm, respectively.
(postscript version)