The calorimeter modules are assigned serial numbers S001 through S240: the pentagons carry the serial numbers S001 through S010, the hexagon A's S011 through S060. The vetoes receive the last twenty numbers S221 through S240. The numbers used in describing the clusters and the superclusters relate to the actual positions of the modules in the calorimeter while the serial numbers describe the properties of the crystals such as the shape, the fast to total, the dimensional accuracy, the light collection uniformity. However, once the calorimeter is assembled only the serial numbers will prevail since at that time the actual position of, say, S001 will be determined: S001, a pentagon whose properties are well documented, could conceivably take any of the positions P01 through P10 shown in figure 6.4.
Figure: The electronic diagram for the pion beta trigger. The Memory Look Up (MLU) makes boolean operations on the inputs which include the supercluster signals, the DPG, etc. As outputs, the MLU produces the desired event triggers which are stored in pattern registers. The Data trigger is the ``OR'' of the various event triggers.