ARGO Dtector Simulation Program Based On Geant4

Regardless of in the accelerator high energy physics or in cosmic rays high energy physics research, the detector is carrier of the experiment, where the experimental phenomenon happens and the experimental data produces, therefore, during the simulation work of the high energy physics experiment, the detector simulation is essential and crucial, and then the simulation detector working condition quality directly will affect the simulation data of experiment.The apparatus of ARGO cosmic rays observation station located at Yangbajing in Tibet consists of a full coverage array of Resistive Plate Chamber. It has high coverage fraction and very good time and spatial resolution characteristic. It can make a more detailed survey on the arrival time and spatial distribution of the EAS particles that arrive the array. Its experimental goal is to study the air shower phenomenon in the small scope using the good natural condition as well as the high elevation area superiority of that local area and so on, then to make further research on such a series of basic questions as cosmic rays, theγstorm astronomy, and so on. The high elevation and the full coverage technology enable the ARGO array to have the ability to detect the small air shower. Its threshold energy of detector is possible to achieve approximately 100GeV. Its energy region of detector can link up with the satellite experiment. And it has covered the energy region blank between the satellite experiment and telescope experiment.In past several years, the ARGO detector simulation was completed based on Geant3 and named as ARGO-G. Geant3 is a kind of detector simulation software developed based on the Fortran language. It is also widly applied in multitudinous high energy physics experiments. But along with the gradual development and widly application of object-oriented programming language C++, people realize, we can develop another kind of simulation software package based on C++ to simulate the high energy physics experiment detector, and this simulation software package is Geant4.This article first introduced the Geant4 software package develoed based on C++ then as well as how to simulate the simple detector to using Geant4. The main content is simulating the detector of ARGO experiment using Geant4 based on C++ and testing the detector by runing the job to find whether the detector we have simulated can achieve the anticipated function and our goal. In the simulation process the ARGO experiment detector has been divided into several relatively independent modules. Different modules realize the joint by the interface routine. In order to read the EAS analog data which produces by the CORSIKA simulation, we had in the instance producing module of this procedure established an interface routine named as "AG4CorsikaInterface". In the procedure all the modules are these as below: run operating control parameter administration module, geometry information management module, detector array structure module, instance producing module, sensitive detector module, hits information digitization module, trigger simulation module and simulation instance output module and so on. When we run the job, the detector must first read the simulation data (main content is EAS particles) produced by CORSIKA through AG4CorsikaInterface in the instance producing module. When the particles simulated by CORSIKA enter the detector, they will affect mutually with the material in detector. Then the sensitive detector inside will be hit and produce hits information. The sensitive detector will record these hits information and digitize them, then digitized hits information will be read by the trigger module and outputed by the instance output module.Through the run of certain instances and comparing our simulation results with experiment data, we finded that the simulation results are consistent with data. Our work has achieved the anticipated goal basicall.