Geometry parameters
The the g e o m e t r y parameters describe the geometry of the layer. All
values are in centimeters. Possible parameters are: R, ZMIN and ZMAX (barrel),
or Z, RMIN and RMAX (forward). In addition, there are also PHI1, PHI2, PHI3,
and EMPTY_TYPE, for both barrel and forward detectors. These can be used
to describe how the layer is sub-divided in sectors in :
A cylinder or a plane can be subdivided in . A repeated form is
called a 'cell'. The first -limit gives the angle of the first edge
of a measuring element (ie. the lowest p o s i t i v e of any measuring
sector starting edge). The second -limit gives the end of this sector,
and the third gives the end of the non-measuring sector (ie. the low-
edge of the second measuring sector). This pattern of measuring and
non-measuring sectors is the assumed to repeat over the full 360 degrees.
The EMPTY_TYPE tells how to interpret the non-measuring sectors : 0 means
that the region is empty, ie. no material, and no measurement, and -1 that
it contains material, but does not measure.