Simulation of Central and Dimuon Events in the ALICE DAQ System.

<P> The Heavy Ion Experiment ALICE is one of the three future experiments in the LHC at CERN. At the ALICE experiment, the detectors will produce two different kinds of data flow simultaneously: very large events (up to 39 Mbyte) at a low rate (40 Hz) and small events (up to 0.25 MByte) at a high rate (up to 1000 Hz). There will be two types of the large events (Central events and Minimum Bias events), whose combined data traffic corresponds to events of up to 40 MByte at 50 Hz event rate, and referred to as central events. The small events are called dimuon events [1]. <P> Previously we have carried out simulations to see how the system performances will vary if one of the basic input parameters is changed, provided that only central events are generated [2]. In this paper we present simulation results when both kinds of events are generated at the same time. The simulation results will show the limits of the data acquisition system, i.e. the input parameter values at which the system is still in equilibrium and the global input data rate just does not exceed the global output data rate. The graphs presented in this paper will probably help to find an optimal parameter set for the DAQ system. <P> We used a simplified version of the simulator program ALSIM [3] which is written in MODSIM II language [4]. <P> In the subsequent chapters, first we describe the simulation setup with the default values of the input parameters, then we present the simulation results, and finally we give a brief summary of the results.