6. Detector description

The detector description files are assumed to be on FORTRAN units 51 and following. It is possible to use more than one detector description at the same time. This is useful for detector performance studies, since it makes it possible to assure that exactly the same events are passed through the different lay-outs. In fact, it is possible to study the differences at the track-by-track level. To activate this possibility, set the steering-card NDETS (default: 1) to the wanted number of detector-layouts. The first lay-out is then read from unit 51, the second from unit 52, etc. (The maximum number is 3, but by recompiling the SGV libraries, changing the parameter NGEOM in the three keep-sequences ZXSIZ, ZTSIZ, and ZASIZ to the wanted value up do 9 geometries can be used simultaneously (if Your computer can take the size of the program...))

The file(s) contain descriptions of the different parts of the detector, as follows :

TYPE:  (detector_type)
  LAYER: (layer_name)
    (REPEAT : TIMES=value, geometry parameter step=value,...)
    GEOMETRY:(geometry parameter=value,geometry parameter=value,...)
    MATERIAL:(material parameter=value,material parameter=value,...)
    MEASUREMENT:(measurement parameter=value,measurement parameter=value,...)
    (ENDREPEAT:)
  LAYER:
    .
    .
    .

Followed by the next detector type, etc.

Any number of empty lines can be inserted in the file, and any line beginning with the characters 'C', 'c', '*' or '!' are treated as comments, and are ignored.

TYPE should be one of BARREL_TRACKING, FORWARD_TRACKING, BARREL_CALORIMETRY, FORWARD_CALORIMETRY, BARREL_TAGGERS, FORWARD_TAGGERS, BARREL_SCINTILATORS, or FORWARD_SCINTILATORS.

The REPEAT function makes it easy to describe repeated layers that only differs by their geometry, and only does so by a constant step. The layer-name, as well as the measurement and material parameters are identical for all layers described by this construction, but the selected geometry parameters are incremented by the step given.