The most stringent requirements on the energy and
time-of-flight resolutions are set by the neutral particle search. Monte-Carlo
studies have shown that an energy resolution of about
, and a time-of-flight resolution of
ns, will provide adequate mass resolution and background
rejection for the neutral search.
The occupancy rate of the calorimeter cells is determined by the particle flux, cell size and the density of the detector. A lead-to-scintillator volume ratio of at least 4:1 would restrict the lateral spread of showers to an acceptable level, and a cell cross section of 10 cm by 10 cm would be granular enough to sufficiently separate showers in E864. Of course, the volume ratio is constrained more by the need to achieve compensation, and the 4:1 ratio has been confirmed by the SPACAL collaboration as appropriate to achieve this end.
The depth of the detector must be long enough to contain a large fraction of the shower, while short enough to keep the cost of the detector within reason. Towers of 100 cm (5.3 interaction lengths) should be adequate.