The Argonne group is investigating various design options and a choice of active medium for the hadronic calorimeter. The group is aiming at developing a design which will lead to an optimal energy resolution for hadronic jets. The approach is based on exploiting the merits of energy flow algorithms, which combine information from both the tracking system and the calorimeter. Issues, such as optimal absorber thickness, lateral segmentation and mode of readout, digital versus analog, are being addressed with detailed Monte Carlo simulation studies of the response of different designs of the calorimeter. The aim is to study these issues based on a realistic simulation of the detector response and using sophisticated clustering algorithms for the energy deposits in the calorimeter. Furthermore, the group is investigating the merits of Resistive Plate Chambers (RPCs) as a choice for the active medium of the hadron calorimeter. RPCs offer a cost-effective and reliable readout system with the possibility of implementing a very fine lateral segmentation, in addition to the layer-by-layer longitudinal segmentation. The group is currently studying the various mechanical parameters of RPCs and their impact on the performance of the hadronic calorimeter. A prototype electronic readout system based on a one-threshold discriminator is being developed to measure the efficiency, noise rate and cross-talk characteristics of the chambers. These initial studies will be followed by the construction of a smaller prototype calorimeter section, containing of the order of 20 layers and a few thousand readout channels. |