An Optical Model for the Prototype Module Performance from Bench Measurements of Components and the Test Module Response to Muons

We have developed an optical model for light collection in the TileCal geometry using bench measurement made on the individual components (clear and waveshift-ing bers, old and new production tiles) taking into account the features of the tower-by-tower readout geometry. The results of this model are in fair agreement with the light yield measured for muons at 90 taken in the May 1995 testbeam. This model has then been applied to the prototype tile and readout geometry. We conclude that in the Module 0 prototype, the light yield per tile may be expected to be similar to that obtained in the test modules and that the longitudinal uniformity is largely unaaected by the diiering tile sizes as a function of radius. No compelling need is found for the use of clear ber welded to WLS bers in the barrel readout where the ber runs are expected to be less than about 2m. However, the signiicantly longer ber lengths expected to be needed for the ber routing in the extended barrel suggest that in this region the use of clear ber welded to WLS ber should be considered if it can be accomplished at an acceptable cost.